JP6758391B2 - Immobilized selenium, its manufacturing method, and use of immobilized selenium in secondary batteries - Google Patents

Description

Cross-reference to related applications This application is filed on February 17, 2016, July 19, 2016, and July 27, 2016, respectively, US Provisional Applications 62 / 296, 286, 62/364, respectively. , 113, and 62 / 367,314 claim priority, the disclosure of which is incorporated herein by reference in its entirety.

Field of Invention This application relates to the field of high energy density lithium secondary batteries. More specifically, the present application relates to a method for producing a carbon-selenium nanocomposite and its use. The present invention also relates to immobilized selenium containing selenium and carbon. The present invention also relates to a method for producing immobilized selenium and practicality. One of the uses of immobilized selenium is in secondary batteries. The present invention can perform charge / discharge cycles at the lowest levels of capacitance attenuation at high rates (eg, 10C rates), and when charged at low rates such as 0.1C rates, it provides electrochemical performance such as specific volume. It also concerns secondary batteries that can be fully recovered.

Description of Related Technologies As human demand for energy increases, secondary batteries with high mass specific energy and high volumetric energy density, such as lithium-sulfur batteries and lithium-sulene batteries, have received widespread interest. I came. Group 6A elements of the periodic table, such as sulfur and selenium, exhibit a two-electron reaction mechanism in the electrochemical reaction process with lithium. Although the theoretical mass-energy specific volume of selenium (675 mAh / g) is lower than that of sulfur (1675 mAh / g), selenium has a higher density (2.07 g / cm ³ ) than sulfur (2.07 g / cm ³ ). It has 4.82 g / cm ³ ). Thus, the theoretical volumetric energy density of selenium (3253mAh / cm ³⁾ is close to the theoretical volumetric energy density of sulfur (3467mAh / cm ^3). At the same time, compared to sulfur, it is electrically closer to an insulating material, and selenium is electrically semi-conductive and exhibits relatively good conductivity. Therefore, compared to sulfur, selenium can exhibit relatively high activity levels and relatively good utilization efficiencies, even at relatively high load levels, leading to high energy and high power density battery systems. It becomes. In addition, the selenium-carbon composite can have further improvements over the sulfur-carbon composite in conductivity, resulting in a highly active electrode material.

As described in Chinese Patent No. 104393304A, the hydrogen selenide gas passes through the graphene dispersion, and the solvent heat reduces graphene oxide to graphene while oxidizing hydrogen selenide to selenium. The selenium graphene electrode material thus produced and 1.5 M lithium bis (trifluoromethanesulfone) imide (LiTFSI) / 1,3-dioxolane (DOL) + dimethyl ether (DME) (volume ratio 1: 1). In combination with the ether electrolyte system, the charge specific volume reaches 640 mA h / g (approaching the selenium theoretical specific volume) in the first cycle. However, in the charge / discharge process, polyselenide ions are dissolved in the electrolytic solution, exhibiting a considerable amount of shuttle effect, which causes a subsequent decrease in capacity. At the same time, the procedure for producing the graphene oxide raw material used in this process is complicated and unsuitable for industrial production.

Chinese Patent No. 1042013389A discloses a positive electrode material for a lithium selenium battery using a current collector of a nitrogen-containing layered porous carbon composite incorporating selenium. When producing a current collector of a nitrogen-containing layered porous carbon composite, a nitrogen-containing conductive polymer is first deposited or grown on the surface of a piece of paper, followed by alkali activation and high temperature carbonization. A nitrogen-containing layered porous carbon composite current collector with carbon fibers as a network structure that supports itself is obtained. Then, selenium is further incorporated into such a composite current collector of nitrogen-containing layered porous carbon. The deposition process for producing conductive polymers is complex and the process for forming or growing a film is difficult to control. The manufacturing process is complex and involves undesired high costs.

In addition, long life, high energy density with high rate charge / discharge performance in electronics, electrical / hybrid vehicles, aerospace / drones, submarines, and other industrial, military, and consumer applications. , And a secondary battery with high output density is required. The lithium ion battery is an example of a secondary battery in the above application. However, the demand for better capacity and cycle performance is not met by lithium-ion batteries. This is because the technology for lithium-ion batteries has matured.

The oxygen atom has an atomic weight of 16 and has the ability to transfer two electrons. Lithium-ion secondary batteries have been studied for the purpose of producing high energy density batteries. If the battery contains an oxygen cathode paired with metallic lithium or metallic sodium as the anode, the battery has the highest stoichiometric energy density. However, most of the technical problems in Li // Na-oxygen batteries remain unsolved.

Element sulfur also belongs to the oxygen group and has the second highest energy density (following oxygen) when paired with the anode of metallic lithium or metallic sodium. Lithium-sulfur batteries or sodium-sulfur batteries have been extensively studied. However, the polysulfide ions (intermediates) formed during the Li-S or Na-S battery discharge step dissolve in the electrolyte and move from the cathode to the anode. Upon reaching the anode, the polysulfide anion reacts with metallic lithium or metallic sodium, resulting in an undesired loss of energy density for the battery system. In addition, sulfur is an insulator and requires a high degree of filling carbon material, even to achieve the lowest levels of conductivity. Due to the extremely low electrical conductivity of sulfur, Li / Na—S secondary batteries are very difficult to discharge or charge at high rates.

This specification discloses a method for producing a two-dimensional carbon nanomaterial having a high degree of graphitization. By combining a two-dimensional carbon nanomaterial and selenium, a carbon-selenium composite material is obtained, which is used as a cathode material paired with an anode material containing lithium, and has high energy density and stable electrochemical properties. A lithium selenium battery can be obtained. A similar process can be used to further assemble the pouch-type cell battery, and the pouch cell also exhibits excellent electrochemical properties.

Also disclosed are methods of making selenium-carbon composites using readily available raw materials and by simple manufacturing procedures.

The selenium-carbon composite material described herein can be obtained from a production method that includes the following steps.

(1) An alkali metal organic salt or an alkaline earth metal organic salt is carbonized at a high temperature, washed with dilute hydrochloric acid or another acid, and dried to obtain a two-dimensional carbon material.

(2) The two-dimensional carbon material obtained in step (1) is mixed with selenium in an organic solution, heated to evaporate the organic solvent, and then a multi-step temperature rise gradient using the two-dimensional carbon material. The selenium is compounded by the method and the soaking method to obtain a carbon-selenium complex.

In step (1), the alkali metal organic salt can be selected from one or more of potassium citrate, potassium gluconate, and sodium sucrose. The alkaline earth metal organic salt can be selected from one or both of calcium gluconate and calcium sucrose. High temperature carbonization can be carried out at 600 to 1000 ° C., preferably 700 to 900 ° C. The carbonization time is 1 to 10 hours, preferably 3 to 5 hours.

In step (2), the organic solvent is from one or more of ethanol, dimethyl sulfoxide (DMSO), toluene, acetonitrile, N, N-dimethylformamide (DMF), carbon tetrachloride, and diethyl ether, or ethyl acetate. Can be selected. The multi-step heating gradient and soaking part (section) is between 200 ° C and 300 ° C, preferably between 220 ° C and 280 ° C, 2-10 ° C / min, preferably 5-5. A heating rate of 8 ° C./min is referred to, followed by a soaking heat treatment for 3-10 hours, preferably 3-4 hours. Next, heating is continued to 400 to 600 ° C., preferably 430 to 460 ° C., followed by soaking heat treatment for 10 to 30 hours, preferably 15 to 20 hours.

Also disclosed herein are lithium-selenium secondary batteries containing the carbon-selenium composites described above. The lithium selenium secondary battery may further include a lithium-containing anode, a separator, and an electrolyte (electrolyte).

The lithium-containing anode is prepared by assembling metallic lithium, a graphite graphite anode material, and a silicon carbon anode material (graphite, a silicon-carbon anode material, and a lithium anode to prepare a half cell, and discharging the anode to form a lithium graphite anode. And prepare the material for the silicon carbon anode). The separator can be, but is not limited to, a commercially available membrane such as a Celgard membrane, Whatman membrane, cellulose membrane, or polymer membrane. The electrolytic solution may be one or more of a carbonate electrolytic solution, an ether electrolytic solution, and an ionic liquid.

The carbonate electrolyte can be selected from one or more of diethyl carbonate (DEC), dimethyl carbonate (DMC), ethylene carbonate (EC), ethyl methyl carbonate (EMC), and propylene carbonate (PC). The solute is one of lithium hexafluorophosphate (LiPF ₆ ), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium perchlorate (LiClO ₄ ), and lithium bis (fluorosulfonyl) imide (LiFSI). Or it can be selected from a plurality of types.

In the ether electrolytic solution, the solvent is selected from one or more of 1,3-dioxolane (DOL), ethylene glycol dimethyl ether (DME), and triethylene glycol dimethyl ether (TEGDME), and the solute is phosphorus hexafluorophosphate. One or more may be selected from lithium acid (LiPF ₆ ), lithium bis (trifluoromethanesulfonyl) imide (LiTFSI), lithium perchlorate (LiClO ₄ ), and lithium bisfluorosulfonylimide (LiFSI).

In the ionic liquid, the ionic liquids are [EMIm] NTf2 (1-ethyl-3-methylimidazolium bistrifluoromethanesulfonimide salt) and [Pyl3] NTf2 (N-propyl-N-methylpyrrolidinbistrifluoromethanesulfonimide). Salt), [PP13] NTf2 (N-propyl-methylpiperidine alkoxy-N-bistrifluoromethanesulfonimide salt), one or more ionic liquids. Also. The solute may be one or more from lithium hexafluorophosphate (LiPF ₆ ), bis (trifluoromethylsulfonyl) imide (LiTFSI), lithium perchlorate (LiClO ₄ ), and lithium bisfluorosulfonylimide (LiFSI). The species can be selected.

The present specification also discloses a pouch-type lithium-selenium cell battery containing a carbon selenium composite material.

Regarding the method for producing the selenium carbon composite material disclosed in the present specification, as compared with the prior art, the two-dimensional carbon material has a raw material that is easily available and low cost, and the production method is simple and practical. With the advantages of being expensive and suitable for mass production, the resulting selenium carbon composite exhibits excellent electrochemical properties.

Immobilized selenium (immobilized selenium form) containing selenium and a carbon skeleton is also disclosed herein. Immobilized selenium comprises at least one of the following: (A) ≧ 9.5 kJ / mol, ≧ 9.7 kJ / mol, ≧ 9.9 kJ / mol, ≧ 10.1 kJ / mol, ≧ 10.3 kJ / mol, or ≧ in order to withdraw from the immobilized selenium system. Selenium particles need to acquire sufficient energy to reach a kinetic energy of 10.5 kJ / mol. (B) 490 ° C. or higher, ≧ 500 ° C., ≧ 510 ° C., ≧ 520 ° C., ≧ 530 ° C., ≧ 540 ° C., ≧ 550 in order for the selenium particles to obtain sufficient energy to break away from the immobilized selenium system. A temperature of ° C. or ≧ 560 ° C. is required. (C) The carbon skeleton has a surface area (20 angstroms) of ≧ 500 m ² / g, ≧ 600 m ² / g, ≧ 700 m ² / g, ≧ 800 m ² / g, ≧ 900 m ² / g, or ≧ 1,000 m ² / g. Has less than a pore). (D) The carbon skeleton has a surface area of 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, and 1% or less of the total surface area (between 20 angstroms and 1,000 angstroms). (About the pores of).

Also disclosed herein are cathode or secondary batteries, including immobilized selenium. Selenium may be doped with other elements such as, but not limited to, sulfur.

Also disclosed herein are selenium and carbon-containing complexes that include platelet forms with aspect ratios of ≧ 1, ≧ 2, ≧ 5, ≧ 10, or ≧ 20.

Also disclosed herein is a cathode comprising a complex containing platelet morphology with aspect ratios of ≧ 1, ≧ 2, ≧ 5, ≧ 10, or ≧ 20 and containing selenium and carbon. Also disclosed herein is a rechargeable battery comprising a complex containing platelet morphology with the above aspect ratios and containing selenium and carbon.

The present specification also discloses a secondary battery including a cathode, an anode, a separator, and an electrolytic solution. The secondary battery can be charged at 0.1C, 0.2C, 0.5C, 1C, 1.5C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, or faster. The cathode may contain at least one element of the Chalcogen family (oxygen group) such as selenium, sulfur, tellurium, and oxygen. The anode may contain at least one element of alkali metals, alkaline earth metals, and Group IIIA metals (s). The separator may include an organic or inorganic separator whose surface can be modified as needed. The electrolytic solution may contain at least one element of an alkali metal, an alkaline earth metal, and a Group IIIA metal (s). The solvent in the electrolytic solution may include a carbonate-based, ether-based, or ester-based organic solvent.

The secondary battery may have a specific capacity of 400 mAh / g or more, 450 mAh / g or more, 500 mAh / g or more, 550 mAh / g or more, or 600 mAh / g or more. The secondary battery may be capable of undergoing an electrochemical cycle such as 50 cycles or more, 75 cycles or more, 100 cycles or more, 200 cycles or more. The secondary battery has a high C rate charge / discharge cycle (for example, 0.1C for 5 cycles, 0.2C for 5 cycles, 0.5C for 5 cycles, 1C for 5 cycles, 2C for 5 cycles, 5C for 5 cycles, And 5 cycles at 10C), at a cycle rate of 0.1C, greater than 30%, greater than 40%, greater than 50%, greater than 60% of the second discharge specific capacitance. The battery specific capacity, which is larger, greater than 70%, or greater than 80%, may be maintained. The secondary battery may have a coulombic efficiency of ≧ 50%, ≧ 60%, ≧ 70%, ≧ 80%, or ≧ 90%. The secondary battery can be used in electronic devices, electric vehicles or hybrid vehicles, industrial applications, military applications such as drones, aerospace applications, marine applications, and the like.

FIG. 1 is a scanning electron micrograph of 50,000 times the carbon material in Example 1. FIG. 2 is a 0.1C charge / discharge curve of the lithium selenium battery in Example 1. FIG. 3 is a 0.1C charge / discharge curve of the lithium selenium battery in Comparative Example 2. FIG. 4 is an optical image of the pouch-type cell battery of Example 1. FIG. 5 is a 0.05 C charge / discharge curve of the pouch-type cell battery of Example 1. FIG. 6 is a flow chart of a method for producing immobilized selenium. FIG. 7 is a scanning electron microscope observation image of the carbon skeleton produced by the process of Example 9. FIG. 8 is an X-ray diffraction pattern of the carbon skeleton produced by the process of Example 9. FIG. 9 is a Raman spectrum of the carbon skeleton produced by the process of Example 9. FIG. 10A is a graph of the cumulative and increasing surface area of the carbon skeleton produced by the process of Example 9. FIG. 10B is a graph of cumulative and increasing pore volume of the carbon skeleton produced by the process of Example 9. FIG. 11A is a graph of TGA analysis for immobilized selenium produced by the process of Example 10. FIG. 11B is a graph of TGA analysis of a non-immobilized selenium sample prepared by the process of Example 10 using Se-Super P carbon and Se graphite. FIG. 11C is a graph of TGA analysis of non-immobilized selenium samples prepared with Se-SuperP carbon (FIG. 11B) at 16 ° C./min and 10 ° C./min heating rates under an argon gas stream. Is. FIG. 11D shows samples of non-immobilized selenium (Se-SuperP complex-solid line) and two different immobilized selenium produced by the process of Example 10 (228-110 (dotted line) and 115-82-2). (Dashed line)) is a graph of the rate constant. FIG. 12 is a graph of the Raman spectrum of immobilized selenium produced by the process of Example 10. FIG. 13 is a graph of the X-ray diffraction pattern of the immobilized selenium produced by the process of Example 10. FIG. 14 is an SEM image of the immobilized selenium produced by the process of Example 10. FIG. 15 is an exploded view of a coin-type cell battery including a cathode manufactured according to the process of Example 11 or 13. FIG. 16 shows a first lithium-selenium coin type cell battery (0.1C) (FIG. 16A-left) and a second lithium-selenium coin type cell battery of the type shown in FIG. 15 manufactured by the process of Example 12. It is a graph of the cycle test result of the cell battery (0.1C and then 1C) (FIG. 16A-right). FIG. 17 is a graph of cycle tests at different cycle rates for the lithium-selenium coin cell batteries of the type shown in FIG. 15 manufactured by the process of Example 12. FIG. 18 is a graph of 0.1 C cycle test results using a polymer separator for the lithium-sulfur-doped selenium coin type cell battery of the type shown in FIG. 15 manufactured according to Example 13. FIG. 19 is a graph of 1C cycle test results using a polymer separator for the lithium-sulfur-doped selenium coin type cell battery of the type shown in FIG. 15 manufactured according to Example 13.

The present invention will be further described below in connection with a specific example. Unless otherwise stated, all test methods in the following examples are conventional. All reagents and materials are available from commercial products.

Example 1:
(A) Production of selenium carbon composite material After pulverization and milling, an appropriate amount of potassium citrate is calcined at 800 ° C. for 5 hours in an inert atmosphere and cooled to room temperature. Wash with dilute hydrochloric acid to neutral pH. It is filtered and dried to obtain a two-dimensional carbon nanomaterial (Fig. 1). The two-dimensional carbon material and selenium are weighed to a mass ratio of 50:50 and then uniformly stirred and mixed with an ethanol solution of selenium. After evaporating the solvent, the mixture is dried in a drying oven. The dried mixture was heated to 240 ° C. at 5 ° C./min and heat treated for 3 hours. Subsequently, the temperature is continuously raised to 450 ° C. at 5 ° C./min. It was heat-treated for 20 hours. Cooling to room temperature gave a selenium carbon composite.

(B) Preparation of selenium carbon composite cathode (positive electrode) The selenium carbon composite manufactured as described above, carbon black Super-P (TIMCAL), and binder CMC / SBR (mass ratio 1: 1) are mixed with water. The selenium carbon composite cathode is obtained by kneading, coating, drying, and other procedures.

(C) Assembly of Lithium-Selenium Battery Lithium by using the selenium carbon composite cathode prepared as described above, a lithium foil as an anode, a cell guard film as a separator, and 1M LiPF _{6 in} EC / DMC as an electrolytic solution. A selenium coin type cell battery and a lithium selenium pouch type cell battery (Fig. 4) were assembled.

(D) Lithium-Selenium Battery Test A constant current-charge / discharge test is performed on a lithium-selenium coin type cell battery and a lithium selenium pouch type cell battery using a charging / discharging device. The test voltage range is between 1.0V and 3.0V and the test temperature is 25 ° C. The specific volume of discharge and the level of charge / discharge current are calculated as standard based on the mass of selenium. The charge / discharge current is 0.1C or 0.05C. The charge / discharge curve of the lithium selenium coin is shown in FIG. 2, and the specific test results are shown in Table 1 below. The test results of the lithium selenium pouch type cell battery are shown in FIG.

Example 2:
The conditions are the same as in Example 1, except that the raw material carbonized for two-dimensional carbon is sodium citrate. The battery test results are summarized in Table 1 below.

Example 3:
The conditions are the same as in Example 1, except that the raw material carbonized for the two-dimensional carbon is potassium gluconate. The battery test results are summarized in Table 1 below.

Example 4:
The conditions are the same as in Example 1 except that the high temperature carbonization temperature of the carbon material is 650 ° C. The battery test results are summarized in Table 1 below.

Example 5:
The conditions are the same as in Example 1 except that the dried mixture was heated to 300 ° C. at 5 ° C./min and heat treated at this temperature for 3 hours. The battery test results are summarized in Table 1 below.

Example 6:
Except that the dried mixture was heated to 240 ° C. at 5 ° C./min, soaked at this temperature for 3 hours, then continued to be heated to 600 ° C., and then soothed at this constant temperature for 20 hours. , The conditions are the same as in Example 1. The battery test results are summarized in Table 1 below.

Example 7:
The conditions are the same as in Example 1, except that the lithium-selenium battery was packaged with a graphite anode lithium oxide instead of the lithium anode sheet. The battery test results are summarized in Table 1 below.

Example 8:
The conditions are the same as in Example 1, except that the lithium-selenium battery was packaged with a silicon-carbon anode in place of the lithium anode sheet. The battery test results are summarized in Table 1 below.

Comparative Example 1:
The conditions are the same as in Example 1 except that polyacrylonitrile was used as a raw material. The battery test results are summarized in Table 1 below.

Comparative Example 2:
The conditions are the same as in Example 1, except that a one-step compounding method is used to produce the selenium and carbon composite. In this example, the dried selenium carbon mixture was heated to 500 ° C. at 5 ° C./min and heat treated at this temperature for 23 hours to obtain a selenium carbon composite material. The charge / discharge curve of the battery made of the selenium carbon composite material thus obtained is shown in FIG. The battery test results are summarized in Table 1 below.

The method for producing a selenium carbon composite material, the method for producing immobilized selenium, and the use of immobilized selenium in, for example, a secondary battery will be described as described above.

Selenium is an element of the same family as oxygen and sulfur, that is, the sixth group of the periodic table of elements. Selenium can be advantageous over oxygen and sulfur in that it has a sufficiently high conductivity. U.S. Patent Application Publication No. 2012/0225352 discloses the manufacture of Li-selenium secondary batteries and Na-selenium secondary batteries with good capacity and cycle capability. However, certain levels of polyserenide anions reciprocate between the cathode and anode of such batteries, resulting in additional electrochemical operation that requires substantial improvement in practical use. References related to this area include:

“Electrode Materials for Rechargeable Batteries”, Ali Aboulmrane and Khalil Amine, US Patent Application 2012/0225352, Sept. 6, 2012.

“Lithium-Selenium Secondary Batteries Having non-Flammable Electrolyte”, Hui He, Bor Z. Jang, Yanbo Wang, and Aruna Zhamu, US Patent Application 2015/0064575, March 5, 2015.

“Electrolyte Solution and Sulfur-based or Selenium-based Batteries including the Electrolyte Solution”, Fang Dai, Mei Cai, Qiangfeng Xiao, and Li Yang, US Patent Application 2016/0020491, Jan. 21, 2016.

“A New Class of Lithium and Sodium Rechargeable Batteries Based on Selenium and Selenium-Sulfur as a Positive Electrode”, Ali Abouimrane, Damien Dambournet, Kerena W. Chapman, Peter J. Chupa, Wei Wang, and Khalil Amine, J. Am. Chem. Soc. 2012, 134, 4505-4508.

“A Free-Standing and Ultralong-life Lithium-Selenium Battery Cathode Enabled by 3D Mesoporous Carbon / Graphene Hierachical Architecture”, Kai Han, Zhao Liu, Jingmei Shen, Yuyuan Lin, Fand Dai, and Hongqi Ye, Adv. Funct. Mater. , 2015, 25, 455-463.

“Micro- and Mesoporous Carbide-Derived Carbon-Selenium Cathodes for High-Performance Lithium Selenium Batteries”, Jung Tai Lee, Hyea Kim, Marin Oschatz, Dong-Chan Lee, FeiXiang Wu, Huan-Ting Lin, Bogdan Zdyrko, Wan Il Chao , Stefan Kaskel, and Gleb Yushin, Adv. Energy Mater. 2014, 1400981.

“High-Performance Lithium Selenium Battery with Se / Microporous Carbon Composite Cathode and Carbonate-Based Electrolyte”, Chao Wu, Lixia Yuan, Zhen Li, Ziqi Yi, Rui Zeng, Yanrong Li, and Yunhui Huang, Sci. China Mater. 2015, 58, 91-97.

“Advanced Se-C Nanocomposites: a Bifunctional Electrode Material for both Li-Se and Li-ion Batteries”, Huan Ye, Ya-Xia Yin, Shuai-Feng Zhang, and Yu-Guo Guo, J. Mater. Chem. A. , May 23, 2014.

“Lithium Iodide as a Promising Electrolyte Additive for Lithium-Sulfur Batteries: Mechanisms of Performance Enhancement”, Feixiang Wu, Jung Tae Lee, Naoki Nitta, Hyea Kim, Oleg Borodin, and Gleb Yushin, Adv. Mater. 2015, 27, 101- 108.

“A Se / C Composite as Cathode Material for Rechargeable Lithium Batteries with Good Electrochemical Performance”, Lili Li, Yuyang Hou, Yaqiong Yang, Minxia Li, Xiaowei Wang, and Yuping Wu, RSC Adv., 2014, 4, 9086-9091.

“Elemental Selenium for Electrochemical Energy Storage”, Chun-Peng Yang, Ya-Xia Yin, and Yu-Guo Guo, J. Phys. Chem. Lett. 2015, 6, 256-266.

“Selenium @mesoporous Carbon Composite with Superior Lithium and Sodium Storage Capacity”, Chao Luo, Yunhua Xu, Yujie Zhu, Yihang Liu, Shiyou Zheng, Ying Liu, Alex Langrock, and Chunsheng Wang, ACSNANO, Vol. 7, No. 9, 8003-8010.

Immobilized selenium, including selenium and carbon, is also disclosed herein. Immobilized selenium can include elemental selenium or compound selenium. Selenium may be doped with other elements, such as, but not limited to, sulfur. Immobilized selenium allows the localization of electrochemically functioning elemental selenium atoms without going back and forth between the cathode and anode of the battery. Immobilization of selenium allows the elemental selenium atom to acquire two electrons during the discharge process and to form a selenium anion at the position where the selenium molecule / atom is immobilized. The selenium anion can then emit two electrons during the charging process to form an elemental selenium atom. Thus, immobilized selenium can act as an electrochemical activator for secondary batteries with specific capacities possible up to stoichiometric levels, as high as ≧ 95%, ≧ 98%, or even 100%. It can have Coulomb efficiency and can achieve significantly improved sustainable cycle capacity.

In batteries manufactured with immobilized selenium, the electrochemical behavior of the elemental selenium atom and the selenium anion during charging is a desirable and properly functioning process. A carbon skeleton with Sp ^2- carbon-carbon bonds has delocalized electrons distributed throughout the conjugated 6-membered ring aromatic π bond over a G-band graphene-like local network suppressed by D-band carbon. In the presence of an electric potential, such delocalized electrons may flow with little or no electrical resistance across the carbon skeleton. Immobilization of selenium, Sp ² carbon of the carbon skeleton - can also be compressed carbon bond, stronger carbon - bring carbon bond, can cause electron conductivity which is improved in the carbon skeleton network. At the same time, selenium immobilization can also cause compression of the selenium particles, resulting in stronger chemical and physical interactions between selenium and selenium, which can improve electrical conductivity between the immobilized selenium particles. When both carbon-carbon and Se-Se bonds are strengthened by selenium immobilization, the carbon-selenium interaction is enhanced by compression, in addition to the presence of stabilized selenium moieties to which the carbon skeleton can be bound. The portion of selenium can serve as an interface layer for the carbon skeleton to successfully immobilize the stabilized selenium moiety. Therefore, electrons can flow between the carbon skeleton and the immobilized seleton with the minimum electrical resistance, and the electrochemical charging / discharging process can function efficiently in the secondary battery. This also allows the secondary battery to maintain near stoichiometric specific capacity, providing cycle characteristics at almost any practical rate while having a low level of loss in the electrochemical performance of the battery. Have.

The carbon skeleton may be porous or may be doped with another component. The pore size distribution of the carbon backbone may range from subangstroms to a few microns, or the pore size distribution uses nitrogen, argon, CO ₂ or other adsorbents as exploration molecules. This may be in the range up to the pore size at which the pore size distribution device can exhibit characteristics. The voids in the carbon skeleton may include a pore size distribution with peaks in at least one of the following ranges: It is between sub-angstroms and 1000 angstroms, or between 1 angstroms and 100 angstroms, or between 1 angstroms and 50 angstroms, or between 1 angstroms and 30 angstroms, and / or 1 angstroms. And 20 angstroms. The voids in the carbon skeleton may further include pores having a pore size distribution with more than one peak within the range described above. Immobilized selenium is advantageous for carbon skeletons with a small pore size, where electrons are rapidly transferred and collected with minimal electrical resistance, allowing selenium to function more electrochemically in the secondary battery. The smaller pore size can also provide more carbon skeleton surface area, where the first portion of selenium can form a first interface layer for the second portion of selenium immobilization. Furthermore, the presence of medium-sized pores in a predetermined proportion and the presence of large-sized pores in a predetermined proportion in the carbon skeleton effectively delivers the solvent lithium ions from the bulk solvent medium to the small pore regions. In this pore region, lithium ions may lose their coordinated solvent molecules and be transported in the solid phase of lithium selenium.

The pore volume of the carbon skeleton may be as low as 0.01 mL / g, as large as 5 mL / g, between 0.01 mL / g and 3 mL / g, or 0. It may be between 03 mL / g and 2.5 mL / g, or between 0.05 mL / g and 2.0 mL / g. Pore volumes with pore diameters of less than 100 angstroms, or less than 50 angstroms, or less than 30 angstroms, or less than 20 angstroms are measured using a BET device with nitrogen, CO ₂ , argon, and other exploration gas molecules. The total measurable pore volume may be greater than 30%, greater than 40%, greater than 50%, greater than 60%, greater than 70%, or greater than 80%. The measured BET surface area of the carbon may be greater than 400 m ² / g, greater than 500 m ² / g, greater than 600 m ² / g, or greater than 700 m ² / g. It may be larger than 800 m ² / g, larger than 900 m ² / g, or larger than 1000 m ² / g.

The carbon may be substantially amorphous or may have very wide peak properties centered on a d-spacing of about 5 angstroms.

Carbon has a Raman peak shift as characterized D- band and G- band, Sp ² carbon - may contain carbon bond. In one example, Sp ² carbon carbon - carbon bond, in the Raman spectrum, and D- band centered at 1364 ± 100 cm ^-1 have a FWHM of approximately 296 ± 50 cm ^-1, about 96 ± 50 cm ^-1 FWHM It is characterized by a G-band centered on 1589 ± 100 cm ^-1 . The ratio of the area of the D-band to the G-band may be in the range 0.01 to 100, 0.1 to 50, or 0.2 to 20.

The carbon can be of any form, eg, platelet-like, spherical, fibrous, needle-like, tubular, irregular shape, interconnected shape, aggregated shape, discrete shape, or any solid particle. You may. Platelet-like, fibrous, needle-like, tubular, or certain forms with a given size aspect ratio may be advantageous for achieving good interparticle contact, which is more It can provide good conductivity and enhance the performance of the secondary battery.

The carbon may be of any particle size, having a median particle size of 1 nanometer to a few millimeters, or a few nanometers to less than 1000 microns, or 20 nm to 100 microns.

The nature of the carbon skeleton can affect the immobilization of selenium, and the interaction between the carbon skeleton surface and the selenium particles can affect the performance of the secondary battery. The placement of Sp ² carbons in the carbon skeleton can help achieve Se immobilization. Small may Sp ² carbon atoms is preferred possibility from carbon skeleton pores, as described in Example 9 herein, can be quantified by NLDFT surface area method. The surface area of the carbon skeleton pores less than 20 ^{angstroms, ≧ 500m 2 / g, ≧} 600m 2 / g, ≧ 700m 2 / g, ≧ 800m 2 / g, ≧ 900m 2 / g, or ≧ 1,000 m ² / It may be g. The surface area from the carbon skeleton pores between 20 angstroms and 1000 angstroms is 20% or less, 15% or less, 10% or less, 5% or less, 3% or less, 2% or less, or 1 of the total surface area of the carbon skeleton. It may be less than or equal to%.

Immobilized selenium can include selenium that evaporates at a higher temperature than elemental selenium, with reference to the definition of selenium evaporation below. The elemental selenium in the Se-Super P complex loses 50% of its mass at a temperature of 480 ° C, and the elemental selenium in the Se / graphite complex is up to 50% of its content at a temperature of 471 ° C. Lose mass. Immobilized selenium has temperatures higher than 480 ° C, such as ≧ 490 ° C, ≧ 500 ° C, ≧ 510 ° C, ≧ 520 ° C, ≧ 530 ° C, ≧ 540 ° C, ≧ 550 ° C, ≧ 560 ° C, ≧ 570 ° C, Or at ≧ 580 ° C. or higher, lose 50% of its mass. In order to escape from the binding force and / or the intermolecular force in the immobilized selenium system and escape to the gas phase, the selenium in the immobilized selenium is ≧ 9.5 kJ / mol, ≧ 9.7 kJ / mol, ≧ 9. It may require kinetic energy of 9 kJ / mol, ≧ 10.1 kJ / mol, ≧ 10.3 kJ / mol, or ≧ 10.5 kJ / mol or more. In one example, the final portion of the vaporized immobilized selenium may require kinetic energy of ≧ 11,635 joules / mol (≧ 660 ° C.) to disengage from the carbon skeleton, and for selenium immobilization. It can be important and can act as an interface material between the carbon skeleton and most of the immobilized selenium molecules. Therefore, the portion of selenium that requires kinetic energy of ≥11,635 joules / mol is referred to as interfacial selenium. The amount of interfacial selenium in the immobilized selenium may be ≧ 1.5%, ≧ 2.0%, ≧ 2.5%, or 3.0% of the total immobilized selenium.

Immobilized selenium may include selenium having a higher activation energy than the activation energy of conventional (non-immobilized) selenium that must be overcome in order for selenium to withdraw from the immobilized Se-C complex system. The activation energy of non-immobilized selenium (Se-Super P complex system) was measured to be approximately 92 kJ / mol according to ASTM method E1641-16. The activation energy of selenium in immobilized selenium containing selenium and carbon is ≧ 95 kJ / mol, ≧ 98 kJ / mol, ≧ 101 kJ / mol, ≧ 104 kJ / mol, ≧ 107 kJ / mol, or ≧ 110 kJ / mol. The activation energy of selenium in the immobilized selenium containing selenium and carbon is ≧ 3%, ≧ 6%, ≧ 9%, ≧ 12%, more than the activation energy of selenium in the Se-Super P complex. ≧ 15% or ≧ 18% larger. Immobilized selenium may be more stable than non-immobilized selenium. The reason is that the immobilization of selenium in the Se-C complex probably minimizes (or eliminates) the round trip of selenium between the cathode and the anode, including immobilized selenium. This is because the battery has improved electrochemically in terms of cycle performance.

Immobilized selenium comprises selenium, which typically has a Raman peak at 255 ± 25 cm ^-1 , or 255 ± 15 cm ^-1 , or 255 ± 10 cm ^-1 , and may be Raman inactive or Raman active. obtain. Raman relative peak intensity is defined as the area of the Raman peak at 255 cm ^-1 with respect to the area of the D-band peak in the carbon Raman spectrum. The immobilized carbon may contain selenium having a Raman relative peak intensity of ≧ 0.1%, ≧ 0.5%, ≧ 1%, ≧ 3%, ≧ 5%. Immobilized selenium is ≧ 5% selenium, ≧ 10% selenium, ≧ 20% selenium, ≧ 30% selenium, ≧ 40% selenium, ≧ 50% selenium, ≧ 60% selenium, or ≧ 70. May contain% selenium.

Immobilized selenium may include selenium with a red shift from the Raman peak of pure selenium. The red shift is defined by the positive difference between the Raman peak position of immobilized selenium and the Raman peak position of pure selenium. Pure selenium typically has a Raman peak at about 235 cm ^-1 . Immobilized selenium is a selenium with a Raman peak red shift up to ≧ 4 cm ^-1 , ≧ 6 cm ^-1 , ≧ 8 cm ^-1 , ≧ 10 cm ^-1 , ≧ 12 cm ^-1 , ≧ 14 cm ^-1 , or ≧ 16 cm ^-1. Can be included. The red shift at the Raman peak suggests that the selenium particles have compression.

Immobilized selenium may contain carbon that may be under compression. Under compression, electrons can flow with minimal resistance, which facilitates rapid electron delivery from the selenium anion involved in the electrochemical process to selenium during the discharge-charging process in the secondary battery. Sp ² carbon of the carbon skeleton containing immobilized selenium - is D- band and / or G- band in the Raman spectrum related to carbon ^{bond, ≧ 1cm -1, ≧ 2cm -1} , ≧ 3cm -1, ≧ 4cm -1, Alternatively, it may show a red shift up to ≧ 5 cm ^-1 .

Immobilized selenium contains selenium which may have a higher collision frequency than non-immobilized selenium. Such high collision frequencies may be due to selenium in the immobilized Se-C system under compression. Collision frequency of selenium non-immobilized selenium according ATSM method E1641-16, was measured to be about 2.27 × 10 ^5. Collision frequency of selenium in immobilized selenium containing selenium and ^{carbon, ≧ 2.5 × 10 5, ≧} 3.0 × 10 5, ≧ 3.5 × 10 5, ≧ 4.0 × 10 5, ≧ 4. ^{5 × 10 5, ≧ 5.0 ×} 10 5, ≧ 5.5 × 10 5, ≧ 6.0 × 10 5, or a ≧ 8.0 × 10 ^5. Immobilized selenium has more ≥10%, ≥30%, ≥50%, ≥80%, ≥100%, ≥130%, ≥150% than the collision frequency of non-immobilized selenium in the Se-C complex. It can have a high collision frequency up to ≧ 180% or ≧ 200%. This can result in better electron conductivity in the immobilized selenium system. This is because there are more collisions between selenium species. Immobilized selenium in the Se-C complex will also have a higher collision frequency with the carbon host wall (eg, carbon backbone). This can result in better delivery or collection of electrons from the carbon backbone during the electrochemical cycle, as well as improvements such as achieving more cycles and cycling at a fairly high C rate, which is highly desirable. It is possible to provide a battery (including immobilized selenium) having a good cycle performance.

Immobilized selenium can contain selenium that is less likely to leave its host material (carbon) and is ≤1 / 5, ≤1 / 10, ≤1 / of the rate constants of non-fixed / conventional selenium. It has a motion rate constant of 50, ≦ 1/100, ≦ 1/500, or ≦ 1/1000. In our example, immobilization selenium comprises less selenium tends to leave the host material ^{(carbon), ≦ 1 × 10 -10,} ≦ 5 × 10 -11, ≦ 1 × 10 -11, ≦ 5 × It has a motion rate constant (50 ° C.) of ^10-12 or ≦ 5 × ^10-13 .

Immobilized selenium may include selenium, which may be amorphous, as determined by X-ray diffraction measurements. Diffraction peaks with a d-spacing of about 5.2 angstroms are relatively small or weak and are, for example, 10% weaker, 20% weaker, 30% weaker, or 40% weaker than the carbon skeleton diffraction peaks.

Immobilized selenium can be produced by physically mixing carbon and selenium and then melting and homogenizing (or mixing or blending) the selenium molecules to achieve selenium immobilization. Physical mixing includes ball mill (dry and wet), mortar and pestle (dry or wet) mixing, jet mill, horizontal mill, grinding mill, high shear mixing in slurry, normal slurry mixing using blades, etc. Can be implemented by The physically mixed mixture of selenium and carbon can be heated at a temperature above the melting point of selenium and below the melting temperature of carbon. Heating may be performed in an inert gas environment such as argon, helium, nitrogen, etc., without limitation. The heating environment may include air or a reaction environment. Immobilization of selenium can be achieved by impregnating the carbon with dissolved selenium and then evaporating the solvent. The solvent for dissolving selenium may include alcohol, ether, ester, ketone, hydrocarbon, halogenated hydrocarbon, nitrogen-containing compound, phosphorus-containing compound, sulfur-containing compound, water and the like.

Immobilized selenium can be obtained by melting large amounts of selenium in the presence of carbon and then removing excess unimmobilized selenium.

An immobilized selenium system or an immobilized selenium body is ≧ 30%, ≧ 40%, ≧ 50%, ≧ 60%, ≧ 70%, ≧ 80%, or ≧ 80% of the total amount of selenium in the system or the body (form). It may contain ≧ 90% immobilized selenium. Non-immobilized selenium can vaporize at a lower temperature than immobilized selenium.

The immobilized selenium system or the immobilized selenium compound may contain immobilized selenium doped with one or more additional elements / other elements from Group 6 of the Periodic Table, such as sulfur and / or tellurium. Good. The dopant concentration may range from as low as 100 mass ppm to as high as 85 mass% of the mass of the immobilized selenium system or the immobilized selenium body.

An example of the process for producing immobilized selenium is shown in FIG. In this process, both selenium and carbon are mixed under dry or wet conditions (S1). After the mixture is dried to powder (S2) as needed, the dry powder can be pelletized as needed (S3). As a result of step S1 and, if necessary, steps S2 and S3, a carbon skeleton as a starting material for step S4 is produced. In step S4, selenium melts in the carbon skeleton. The selenium melted in the carbon skeleton can be dried, thereby producing the immobilized selenium in step S5. The production and characterization of immobilized selenium is described later herein in connection with Example 10.

Immobilized selenium can be used as the cathode material for secondary batteries. To make the cathode, the immobilized selenium may be dispersed in a liquid medium such as, but not limited to, water or an organic solvent. The cathode containing immobilized selenium can include a binder, another binder if necessary, a conductivity accelerator if necessary, and a current collector. The binder may be an inorganic substance or an organic substance. The organic binder may be a natural product such as CMC or a synthetic product such as SBR rubber latex. The conductivity accelerator may be one of carbon such as graphite-derived small particles, graphene, carbon nanotubes, carbon nanosheets, and carbon black. The current collector may be, for example, an aluminum foil, a copper foil, a carbon foil, a carbon fiber, or another metal foil. The cathode can be produced by applying an immobilized selenium-containing slurry (or a plurality of types of slurry) to the current collector, and subsequently by a typical drying step (air drying, oven drying, vacuum oven drying, etc.). The immobilized selenium slurry or the plurality of kinds slurries can be produced by a high shear mixer, a regular mixer, a planetary mixer, a double planetary mixer, a ball mill, a vertical atelier, a horizontal mill and the like. Cathodes containing immobilized selenium may be stamped or roller milled (or calendared) prior to use in the battery assembly.

A secondary battery containing immobilized selenium can include a cathode containing immobilized selenium, an anode, a separator, and an electrolytic solution. The anode is lithium, sodium, silicon, graphite, magnesium, tin, and / or appropriate and / or desirable elements from Group IA, IIA, IIIA, etc. in the Periodic Table of the Elements (Periodic Table), or them. It can include a combination of elements. The separator may include an organic separator, an inorganic separator, or a solid electrolyte separator. Organic separators can include, for example, polymers such as polyethylene, polypropylene, polyester, halogenated polymers, polyethers, polyketones and the like. The inorganic separator may include glass fiber, quartz fiber, and a solid electrolyte separator. The electrolytic solution may contain a lithium salt, a sodium salt, or another salt, a salt of Group IA of the Periodic Table, a salt of Group IIA of the Periodic Table, and an organic solvent. The organic solvent may include an organic carbonate compound, ether, alcohol, ester, hydrocarbon, halogenated hydrocarbon, lithium-containing solvent and the like.

Secondary batteries containing immobilized selenium can be used for electronic devices (electronics), electric vehicles or hybrid vehicles, industrial applications, military applications such as drones (unmanned aircraft), aerospace applications, marine applications, etc.

The secondary battery containing immobilized selenium can have a specific capacity of 400 mAh / g or more, 450 mAh / g or more, 500 mAh / g or more, 550 mAh / g or more, or 600 mAh / g per selenium activity amount. A secondary battery containing immobilized selenium can undergo an electrochemical cycle in 50 cycles or more, 75 cycles or more, 100 cycles or more, and 200 cycles or more.

Secondary batteries containing immobilized selenium, 0.1C, 0.2C, 0.5C, 1C, 1.5C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, or better. It can be charged quickly. A wide range of high C rate charge / discharge cycles of 30 cycles or more (eg, 0.1C 5 cycles, 0.2C 5 cycles, 0.5C 5 cycles, 1C 5 cycles, 2C 5 cycles, 5C After 5 cycles (5 cycles at 10C), the secondary battery containing immobilized selenium was charged at a cycle rate of 0.1C at> 30%,> 40%,> 50% of the specific capacity of the second discharge. ,> 60%,> 70%,> 80% battery specific capacity can be maintained.

The following are some examples for explaining the concept of the present invention. However, these examples should not be construed in a limited sense.

Characterization method Scanning electron microscope (SEM) images were collected in a Tescan Vega scanning electron microscope equipped with an energy dispersive X-ray (EDX) detector.

Raman spectra were collected by a Renishaw in Via Raman spectrometer (confocal). Laser Raman spectroscopy is widely used as a well-established characterization of carbon and diamond, making it easy to distinguish between various forms (allotropes) of carbon (eg, diamond, graphite, buckyball, etc.). Provide features that can be done. Combined with photoluminescence (PL) technology, it is non-destructive to examine various properties of diamond such as phase purity, crystal size and orientation, defect level and structure, impurity type and concentration, stress and strain. This method provides a method. In particular, primary diamond Raman peak width at 1332 cm ^-1 (FWHM, FWHM), and, between the diamond peak and the graphite peak (G-band at D- band and 1600 cm ^-1 in 1350 cm ^-1) Raman strength ratio is a direct indicator of the quality of diamond and other carbon materials. In addition, the level of stress and strain in diamond or other carbon particles and films can be estimated from the diamond Raman peak shift. It is reported that the diamond Raman peak shift speed under hydrostatic stress is about 3.2 cm ^-1 / GPa, the peak shifts to a low wave number under tensile stress, and the peak shifts to a high wave number under compressive stress. Has been done. The Raman spectra discussed herein were collected using a Renishaw in Via Raman spectrometer using a 514 nm excitation laser. More information on using Raman spectroscopy to characterize diamonds can be found in (1) AM Zaitsev, Optical Properties of Diamond, 2001, Springer, and (2) S. Prawer, RJ Nemanich, Phil. It is also possible with reference to Trans. R. Soc. Lond. A (2004) 362, 2537-2565.

Data relating to the BET surface area and pore size distribution of the carbon sample were measured by nitrogen absorption and CO ₂ absorption using 3Flex (Mircomeritics) equipped with Smart VacPrep for the production of degassed samples. Samples are typically degassed in Smart Vac-Prep under vacuum for 2 hours at 250 ° C. prior to measurement of CO ₂ and N ₂ absorption. BET surface area is measured using nitrogen absorption. The pore size distribution of the carbon sample was calculated by combining the nitrogen absorption data and the CO ₂ absorption data. For more information on combining both N ₂ and CO ₂ absorption data to determine the pore size distribution of carbon materials, see “Dual gas analysis of microporous carbon using 2D-NLDFT heterogeneous surface model and combined adsorption data of N _2”. and CO ₂ ”, Jacek Jagiello, Conchi Ania, Jose B. Parra, and Cameron Cook, Carbon 91, 2015, pages 330-337.

Data relating to thermogravimetric analysis (TGA) and TGA-differential scanning calorimetry (DSC) were measured for the immobilized selenium sample and the control sample by Netzsch Thermal Analyser. Perform TGA analysis at 16 ° C./min, 10 ° C./min, 5 ° C./min, 2 ° C./min, 1 ° C./min heating rates, and other heating rates at ~ 200 mL / min argon flow rates. Carried out. For the purpose of consistency, the typical amount of immobilized selenium sample used for TGA analysis was about 20 mg.

The activation energies and collision frequencies of immobilized and non-immobilized selenium were measured by TGA according to the procedure described in ASTM Method E1641-16.

X-ray diffraction results were collected on the Philip Diffractometer for various carbon, Se-carbon samples, and immobilized selenium.

The battery cycle performance of a secondary battery containing immobilized selenium was tested in a Lanhe CT2001A battery cycle tester. Depending on the amount of selenium contained in the immobilized selenium and the cycle rate (0.1C, 0.5C, 1C, 2C, 3C, 4C, 5C, 10C, etc.), the charge / discharge current of the secondary battery containing the immobilized selenium can be determined. It was measured.

Example 9: Synthesis and characterization of carbon skeleton 260 g of potassium citrate filling was placed in a crucible and the crucible was placed in a quartz tube in a tube furnace to form the first residue. An argon gas stream was passed through the furnace and the furnace was heated from room temperature (~ 20-22 ° C.) to 600 ° C. at 5 ° C./min. The furnace was kept at this temperature for 60 minutes, then the furnace was shut down, and after cooling the furnace, the filling was removed from the crucible and 174.10 g of treatment residue was recovered. To form the second and third treatment residues, the same steps as described for the first residue were repeated separately for 420 g and 974 g of potassium citrate filler. The obtained second and third treatment residues were 282.83 g and 651.93 g, respectively.

1108.9 g of these three treatment residues were put together into a crucible, which was placed in a quartz tube in a tube furnace, and an argon gas stream was poured into the furnace. The temperature of the furnace was raised to 800 ° C. at 5 ° C./min. The furnace was kept at 800 ° C. for 1 hour. After cooling the furnace, the crucible was removed from the quartz tube and then 1,085.74 g of the first final residue was recovered.

According to the same procedure (800 ° C.) as described in this example, the filling of 120 g of potassium residue introduced into the furnace produced about 77 g of a second final residue (800 ° C.).

The combination of the first final residue and the second final residue resulted in approximately 1,163 g of the third final residue.

1,163 g of the third final residue was mixed with 400 mL of water to prepare a slurry, which was divided into four 2 liter beakers approximately equally. It was measured that the pH of each slurry was greater than 13. Next, a concentrated hydrochloric acid solution was added to each beaker with intense carbon dioxide generation and precipitated at a pH of less than about 5. More hydrochloric acid solutions were added to give a pH of about 1.9. Subsequently, the filtered cake obtained by filtering and washing the slurry was dried in an oven at 120 ° C. for about 12 hours, and then vacuum dried at 120 ° C. for 24 hours to obtain four carbon skeleton samples. The total weight was about 61.07 g.

Characterization of these carbon skeleton samples was performed by SEM, XRD, Raman, BET / pore size distribution. The SEM result of the carbon skeleton of No. 1 is shown in FIG. The surface morphology of typical carbon skeleton particles produced by the method described in this example has a sheet-like morphology, the sheet edges of which are interconnected with a sample thickness between 500 nm and 100 nm. The sample width (or length) was between 0.5 μm and 2 μm. Therefore, the aspect ratio (defined by the longest ratio of the sample width (or sheet length) to the sample thickness) is ≧ 1, for example, the aspect ratio ≧ 5 or larger, or the aspect ratio ≧ 10. is there.

The X-ray diffraction pattern of the carbon skeleton of 1 shown in FIG. 8 indicates that the carbon skeleton is substantially amorphous in the phase. However, it shows a wide diffraction peak centered around 2θ at about 17 °, showing a d-spacing of about 5.21 angstroms.

The results of Raman scattering spectroscopy of the first carbon skeleton shown in FIG. 9, this is the FWHM of the 296cm ^-1 and 96cm ^-1, respectively, and at about 1365cm ^-1 D- band (curve 1), about 1589cm ^-1 of G- band showing the Sp ² carbon having (curve 2) and. Both the D-band and G-band show a mixture of Gaussian and Lorentz distributions. The D-band has a Gaussian distribution of about 33% and the G-band has a Gaussian distribution of about 61%. The area ratio of the D-band to the area of the G-band is about 3.5.

By nitrogen adsorption, the BET surface area of one carbon skeleton was measured to be 1,205 m ² / g. Increasing pore surface area vs. pore width is plotted in FIG. 10A using the NLDFT method, indicating a cumulative pore surface area of 1,515 m ² / g. The discrepancy between the BET surface area and the NLDFT surface area may be due to the fact that the NLDFT distribution is calculated using both nitrogen and CO ₂ adsorption data. CO ₂ molecules can enter pores that are smaller than the pores in which nitrogen molecules can enter. The NLDFT surface area in pores with peaks at 3.48 angstroms is 443 m ² / g, 859 m ² / g at 5.33 angstroms, and 185 m ² / g at 11.86 angstroms (up to 20 angstroms). is there. The total NLDFT surface area from the pores between 20 angstroms and 1000 angstroms is only 7.5 m ² / g, which is greater than 20 angstroms, while the total is 1,502 m ² / g for pores of 20 angstroms or less. The surface area from the pores is only about 0.5% of the total surface area.

The pore size distribution of the carbon skeleton sample was determined by nitrogen absorption and CO ₂ absorption. The pore size distribution shown in FIG. 10B was obtained by combining the absorption results from nitrogen absorption and CO ₂ absorption. The relationship of increasing pore volume (mL / g) to pore width (angstrom) indicates that there are three major peaks located at 3.66 angstroms, 5.33 angstroms, and 11.86 angstroms. The relationship between cumulative pore volume (mL / g) and pore width (angstrom) is that there are about 0.080 mL / g pores below the 3.66 angstrom peak and about 0 below the 5.33 angstrom peak. It shows that there are .240 mL / g pores and about 0.108 mL / g below the peak of 11.86 angstroms, with 0.43 mL / g pores below 20 angstroms and 20 angstroms. It shows that it has 0.042 mL / g of pores between and 100 angstroms and 0.572 mL / g in total of pores up to 1000 angstroms.

Example 10: Production of Immobilized Selenium and Evaluation of Characteristics 0.1206 g of selenium (indicating bulk characteristics of selenium) was placed in a set of agate mortar and pestle, and 0.1206 g of carbon skeleton produced according to Example 9 was added. Place in the same agate mortar and pestle. The mixture of selenium and carbon skeleton is manually ground for about 30 minutes and the ground mixture of selenium and carbon skeleton is transferred to a stainless steel die (10 mm in diameter). The mixture in the mold is compressed at a pressure of about 10 MPa to form pellets of the mixture. The pellets are then placed in a sealed container in the presence of an inert environment (argon) and the sealed container containing the pellets is placed in an oven. An oven containing a sealed container containing pellets is heated to 240 ° C. (above the melting temperature of selenium), for example 12 hours. However, any combination of time and temperature above the melting point of selenium, which can partially or completely react selenium with carbon to form immobilized selenium with some or all of the characteristics described herein. Expected to be used. Then, after returning the pellets to room temperature, the pellets are removed from the container. The removed pellet is the immobilized selenium of Example 10.

The immobilized selenium of Example 10 was characterized by TGA-DSC and TGA. The TGA-DSC analysis results were collected for immobilized selenium at a heating rate of 10 ° C./min under an argon gas of 200 mL / fraction. There is no endothermic DSC peak observable at a temperature near the melting point of selenium (about 230 ° C.), which causes the immobilized selenium of Example 10 to have a melting point at about 230 ° C. where the endothermic peak should be. It is shown that it differs from the bulk form of the power selenium molecule / atom.

Studies have shown that the TGA-DSC data may be unreliable when the heating temperature reaches the temperature at which selenium molecules begin to detach from the TGA-DSC sample crucible (graphite or ceramics). It is believed that this causes vapor phase selenium molecules (from the sample crucible) to enter the argon carrier gas stream and react with the platinum sample holder of TGA-DSC to distort the actual TGA-DSC thermochemical behavior. Selenium molecules released from the sample crucible and reacting with the platinum sample holder result in lower mass loss in this temperature range. The selenium-platinum complex in the platinum sample holder is then released into the gas phase when the heating temperature reaches a point above 800 ° C. Complete release of selenium can occur at 1000 ° C. This study used most of the immobilized selenium samples of Example 10. Therefore, a new sample (~ 16g) of immobilized selenium was prepared using the same method as described in the first half of Example 10.

The thermochemical behavior of this new immobilized selenium sample was studied by TGA analysis using a ceramic sample holder covering a very small thermocouple used for TGA analysis. The TGA analysis result of this new immobilized selenium sample is shown in FIG. 11A. FIG. 11A is in line with the TGA analysis results (FIG. 11B) and is a selenium-carbon composite (50-50, Se-Super P carbon composite) in the same process as the production of immobilized selenium in Example 10. (Made with body and Se-graphite (crushed graphite)). Super P is a commercial grade carbon black widely used in the lithium-ion battery industry. Milled graphite was produced by milling Poco 2020 graphite. The TGA analysis data are also summarized in Table 2 below.

Immobilized selenium can have an initial mass loss temperature starting at about 400 ° C. In contrast, the Se-Super P carbon composite and the Se-graphite carbon composite may have an initial mass loss temperature starting at about 340 ° C. The intermediate mass loss temperature of the immobilized selenium can be about 595 ° C. On the other hand, the temperature may be 480 ° C. in the case of the Se-Super P composite material and 471 ° C. in the case of the Se-graphite composite material. The major mass loss was completed at about 544 ° C. for the Se-Super P and Se-graphite composites and at 660 ° C. for the immobilized selenium. The Se-Super P carbon composite and the Se-graphite carbon composite showed less than 0.6% mass loss between 560 ° C and 780 ° C, and immobilized selenium showed the bottom of the major mass loss (~ 660). It shows a mass loss of about 2.5% from (up to 1000 ° C). These results suggest that non-immobilized selenium (Se-Super P carbon complex and Se-graphite complex) accounts for less than 1.2% of the total selenium that can leave the complex at a temperature of ≥560 ° C. On the other hand, the immobilized selenium has about 5.0% of the total selenium capable of detaching from the carbon skeleton at a temperature of ≧ 660 ° C. or higher. The following details are provided to provide examples that provide insights into thermochemical behavior. However, these details should not be construed in a limited sense.

Using the data of the intermediate mass loss temperature of TGA as an example of thermochemical behavior, when the heating temperature rises, the kinetic energy of the selenium molecules in the Se-Super P complex and the Se-graphite composite is the selenium molecule. Escape from the intermolecular interaction of selenium and rise to the level at which selenium molecules have sufficient energy to leave the liquid phase. Here, kinetic energy = 3RT / 2, R is a gas constant, and T is a temperature in Kelvin units.

The average kinetic energy of the selenium molecules in the Se-Super P complex was measured to be 9,391 joules / mol when the selenium molecules were withdrawn from the mixture of the Se-Super P complex. However, in order for selenium to move away from the carbon backbone to the gas phase selenium molecule, immobilized selenium requires more energy than it has an average kinetic energy of about 10,825 joules / mol. It is believed that selenium in immobilized selenium can chemically interact with selenium and the carbon skeleton as either an atomic state, a molecular state, or an arbitrary state, overcoming intermolecular interactions with selenium. .. In addition, the last portion of selenium that disengages from the carbon skeleton between 660 ° C and 1,000 ° C has an average kinetic energy in the range of 11,635 joules / mol to 15,876 joules / mol or more. This suggests that selenium in immobilized selenium is more stable than selenium in conventional selenium-carbon composites. The stabilized selenium in the immobilized selenium of Example 10 is an electrochemical process such as a charge / discharge cycle of a secondary battery in which the selenium in either the atomic state, the molecular state, or the arbitrary state is composed of the immobilized selenium. Improves the ability to stay inside the carbon skeleton. In one example, the last portion of selenium may require kinetic energy of ≧ 11,635 joules / mol (≧ 660 ° C.) to dissociate the carbon skeleton and is important for selenium immobilization. It has the potential to act as an interface material between the carbon skeleton and most of the immobilized selenium molecules. The portion of interfacial selenium in the immobilized selenium can be ≧ 1.5%, ≧ 2.0%, ≧ 2.5%, or 3.0% of the total immobilized selenium.

FIG. 11A also shows a TGA study of immobilized selenium, which has a temperature of 628 ° C. for the intermediate mass loss point of the contained selenium at a heating rate of 16 ° C./min. As shown in FIG. 11C, in the case of the Se-Super P composite material, the temperature at the heating rate of 16 ° C./min and the intermediate mass loss of the contained Se is 495 ° C. Various heating rates (eg 16 ° C./min, 10 ° C./min, 5 ° C./min, 2.5 ° C./min, and 1 ° C./min) were adopted for ASTM E1641-16 and E2958-14. The activation energy and collision frequency can be measured and calculated using such known methods. Table 3 below shows the mass loss temperature of 15% at various heating rates.

Activation energy of selenium (non-immobilized or conventional) of Se-Super P complex, in the collision frequency of 2.27 × 10 ^5, was determined to be 92.3KJ / mol. Activation energy of selenium in immobilized selenium (228-110 above) also in the collision frequency of 12.4 × 10 ^5, was determined to be 120.7KJ / mol. Another sample of immobilized selenium was prepared in the same process as in Example 10 (155-82-2 above) also, 120.0KJ / mol activation energy, and the collision frequency of 18.3 × 10 ⁵ It was measured to have.

The rate constant of selenium is calculated using the Arrhenius equation.
Here, k is the rate constant, Ea is the activation energy, A is the collision frequency, R is the gas constant, and T is the temperature in Kelvin units.

With reference to FIG. 11D, the activation rate constants were calculated using the Arrhenius equations at various velocities using the activation energies and collision frequencies measured above. FIG. 11D shows that non-immobilized selenium (Se-Super P complex-solid line) has a much higher rate constant than immobilized selenium (228-110 (dotted line) and 115-82-2 (dashed line)). For example, it is about 4 orders of magnitude larger at 35 ° C. and about 3 orders of magnitude larger at 100 ° C. In one example, at 50 ° C., immobilized selenium has rate constants of 7.26 × 10 ¹⁴ (155-82-2) and 3.78 × 10 ¹⁴ (228-110), while non-immobilized selenium (Super). The rate constant of P) is 2.668 × 10 ^-10 . Selenium with a lower rate constant is less likely to leave the host material (carbon), which can result in better battery cycle performance.

Figure 12 shows the spectrum of the immobilized selenium having a Raman peak of G- bands at D- band and 1596cm ^-1 of at 1368cm ^-1, a ratio of the area of the D- band to the area of the G- band 2 It is 8.8. Compared to the Raman spectrum of the carbon skeleton shown in FIG. 9, selenium immobilization shifts both Raman peaks to the higher wavenumber side, with a red shift of about 3 cm ^-1 for the D-band and about about 3 cm- ¹ for the D-band. There are red-shift of 7 cm ^-1, This suggests that the binding strength of Sp ² carbon in the carbon skeleton has been enhanced, for D- band is red shift of about ^{4 cm -1,} G- There is a red shift of about 8 cm ^{-1 for} the band. At the same time, the ratio of the area of the D-band to the area of the G-band also decreases from about 3.4 to 2.8, making the D-band relatively weak or the G-band relatively strong. It was suggested that A stronger G-band may be desirable. This is because the G-band may be associated with a carbon species whose carbon skeleton is capable of more easily conducting electrons and which is desirable for electrochemical performance when used in a secondary battery. Bulk selenium or pure selenium typically exhibits a sharp Raman peak shift at about 235 cm ^-1 . For immobilization selenium, Raman spectra of FIG. 12 is about 257cm showed a broad Raman peak (12.7% of the area of the G- band) ^-1, a new broad hump at about 500 cm ^-1 (hump, shoulder) (3.0% of G-band area) is shown. Immobilization of selenium alters the Raman characteristics for both carbon skeleton and selenium, all of the Raman peaks are believed to shift to higher wave numbers, whereby, the carbon in the carbon skeleton - carbon Sp ² bond, and, It is suggested that both selenium-selenium bonds of selenium are under compression.

Compression due to immobilization of selenium, carbon in the carbon skeleton - carbon Sp ² bonds, and to strengthen both the Se-Se bonds in the selenium, selenium - produce stronger interaction selenium - selenium and carbon. Therefore, more kinetic energy is required for selenium to escape from the stronger Se-Se bond and the stronger carbon-selenium interaction, which is the immobilized selenium vs. Se-Super P composite. And the reasons for the observations of the TGA analysis in the Se-graphite composite will be explained.

Furthermore, under compression, the carbon skeleton is considered to have better electron transfer capacity at the bond level, and under compression, the selenium atom or molecule is also considered to have better electron transfer capacity.

Stabilized selenium in immobilized selenium, with improved electron conductivity across the carbon backbone and selenium, can be, for example, increased specific capacitance of active material with minimal reciprocating motion, improved cycle performance due to immobilization, high rate. May be desirable in electrochemical processes such as charge / discharge capacity in. However, this should not be interpreted in a limited sense.

The X-ray diffraction pattern for immobilized selenium produced according to Example 10 shown in FIG. 13 shows a decrease in intensity of wide diffraction peaks from a carbon backbone with a d-spacing of about 5.21 angstroms, an intensity of only about 1/3. Is shown. This suggests that immobilized selenium further makes the carbon skeleton more irregular or disrupts the order of the carbon skeleton. In one example, this compressive force is carbon - presumably because that is applied to the carbon Sp ² bond.

FIG. 14 shows an SEM image of the immobilized selenium produced according to Example 10 and shows a sheet-like morphology similar to the image of the carbon skeleton of FIG. There is about 50% selenium immobilized on the carbon skeleton, but many have high aspect ratios with no selenium particles observed on the surface of the carbon skeleton, except that the bonds between the sheets are broken. A flat sheet will be obtained. These sheet-like forms can be highly desirable for forming oriented coatings aligned along the direction of a flat sheet, creating surface-to-surface contact between the sheets and electricity between the sheets. It provides improved conductivity, which can lead to better electrical performance in electrochemical processes, such as in secondary batteries.

Example 11: Production of Se cathode In a mortar and pestle, 56 mg of immobilized selenium prepared according to Example 10, 7.04 mg of Super P, and 182 μL of carboxymethyl cellulose (CMC) solution (1 mg for every 52 μL of CMC solution). (Contains dry CMC), 21.126 μL of SBR latex dispersion (each 6.03 μL of SBR latex dispersion contains 1 mg of dry SBR latex), and 200 μL of deionized water are added. The particles, binder, and water are manually pulverized for 30 minutes into a slurry to make a cathode slurry. Next, the cathode slurry was applied onto one side of a piece of conductive substrate, such as a foil, and air dried. In one example, the conductive substrate or foil may be an aluminum (Al) foil. However, this should not be construed in a limited sense, as the use of any suitable and / or desirable conductive material of any shape or form is envisioned. The use of Al foils to form selenium cathodes will be described herein for purposes of illustration only. However, this should not be interpreted in a limited sense.

Next, the Al foil coated with the slurry was placed in a drying oven and heated at a temperature of 55 ° C. for 12 hours to obtain a selenium cathode. The cathode is composed of a dry sheet of immobilized selenium on one side of the Al foil, and the other side of the Al foil is uncoated, i.e., exposed aluminum.

Subsequently, the selenium cathode was punched into a cathode disk having a diameter of 10 mm, respectively. Some of these cathode disks were used as cathodes for secondary batteries.

Example 12: Assembling and Testing a Li-Se Secondary Battery Using the cathode disk from Example 11, the Li-Se coin is described in the embodiment shown in FIG. 15 and discussed below. The mold cell secondary battery was assembled. In this embodiment, the cathode disk 4 having a diameter of 10 mm from Example 11 is arranged on the base 2 of a 2032 stainless steel coin-shaped cell can that functions as a positive case of a coin-type cell battery (“positive case” in FIG. 15). did. The immobilized selenium sheet 5 faces upward away from the base 2 of the positive case, and the exposed side of Al comes into contact with the base 2 of the positive case facing each other. Next, a battery separator 6 (diameter 19 mm, thickness 25 μm) in contact with the immobilized selenium sheet 5 was installed on the cathode disk 4. In one example, the battery separator 6 may be an organic separator, an inorganic separator, or a solid electrolyte separator. The organic separator can be a polymer such as polyethylene, polypropylene, polyester, halogenated polymer, polyether, polyketone and the like. Inorganic separators can be made from glass and / or quartz fibers.

Next, 240 μL of an electrolytic solution 7 containing LiPF ₆ (1M) in an ethylene carbonate (EC) and dimethyl carbonate (DMC) solvent (mass 50-50) was introduced into the positive case 2, followed by the separator 6. A lithium foil disk 8 (15.6 mm in diameter and 250 microns in thickness) was placed on the surface opposite to the cathode disk 4. Next, a stainless steel (SS) spacer 10 is placed on the side of the lithium foil disc 8 opposite to the separator 6, and then, for example, a nickel foam disc 12 is placed on the side of the SS spacer 10 opposite to the lithium foil disc 8. One or more sheets were placed. The lithium foil 8, SS spacer 10, and / or foam disk 12 can function as an anode. Finally, the case 14 made of 2032 stainless steel 14 is on the opposite side of the nickel foam disc 12 from the SS spacer 10 in order to function as the shade case of the coin-shaped cell (the "shadow case" in FIG. 15). It was placed on the edge of the positive case 2. Next, the positive case 2 and the negative case 14 were integrally sealed under high pressure, for example, at 1,000 psi. Sealing of positive and negative cases (2,14) under high pressure includes cathode disc 4, separator 6, lithium foil 8, SS spacer 10, and Ni foam disc 12 (from bottom to top in FIG. 15). It also had the effect of integrally compressing the laminate. Using the above battery separator and glass fiber separator, a dozen or more coin-type cell batteries were assembled. Next, the assembled coin-type cell battery was tested under the following conditions.

The Lanhe Battery Tester CT2001A was used to test some of the assembled coin-operated cell ponds at charge / discharge rates of 0.1C and 1C. Each coin cell battery was tested below. (1) Rest for 1 hour. (2) Discharge to 1V. (3) Rest for 10 minutes. (4) Charge up to 3V. (5) Rest for 10 minutes. Repeat steps (2)-(5) for the cycle test.

FIG. 16A (left) shows the cycle test results (313 cycles at a charge / discharge rate of 0.1 C) for a coin-shaped cell manufactured according to Example 12 using a cathode manufactured according to Example 11. This shows good cycle stability, and the specific volume after 313 cycles is 633.7 mAh / g, which is a retention rate of 93.4% of the initial specific volume. The specific volume of the first discharge was higher than the stoichiometric value, probably due to some side reactions on the cathode and anode surfaces. From the second cycle, the specific volume decreased with the cycle at the beginning. However, the specific volume increased slightly from about 30 cycles to about 120 cycles before steadily decreasing at about 180 cycles. FIG. 16B (right) also shows excellent cycle stability (100 cycles at 0.1C, then 500 cycles at 1C) for another coin cell, with a specific capacity of 462.5mAh / g at 600 cycles. This is the retention rate of 66.0% of the second cycle capacity at 0.1C or the retention rate of 80.3% of the 105th cycle capacity at 1C. Coulomb efficiencies can be as high as ≧ 95%, ≧ 98%, or even 100%, suggesting that the amount of selenium reciprocating between the cathode and anode is undetectable. This electrochemical performance is thought to be the effect of immobilized selenium in the cathode, preventing the selenium from dissolving and moving from the cathode 14 to the anode 2.

FIG. 17 shows cycle test results at various discharge-charge cycle rates (between 0.1C and 10C) for coin-shaped cells assembled using the polymer separators described in Example 12. The test protocol was similar to the test above, except for the cycle rates (0.1C, 0.2C, 0.5C, 1C, 2C, 5C, and 10C). Five cycles of charging and discharging were performed for each C rate. Next, the cycle rate was returned to 0.1 C cycle. At a 0.1 C rate, the battery showed a specific capacity near the stoichiometric value. In addition, the batteries showed good cycle stability at cycle rates of 0.2C, 0.5C, 1C, and 2C. The battery also showed fast charge and fast discharge capacity, cycling 56% of the stoichiometric capacity at 10C rate, but showed a decrease in specific capacity with the cycle. In other words, at the 10C rate, the battery took 3.3 hours to charge and discharge to a capacity of 56% of the stoichiometric value. Under such a high cycle rate, the life of a conventional battery cannot be expected.

The Li-Se battery containing immobilized selenium can recover its capacity to 670 mAh / g, 98% of the total capacity when cycled at a rate of 0.1 C at the start of the test. (1) Stabilization of selenium at the immobilized selenium cathode prevents selenium from leaving the carbon skeleton and reciprocating between the cathode and anode during the cycle, thereby the battery. Cycle performance can be improved. (2) Sp ² carbon - carbon bonds and carbon skeleton, selenium - selenium bonds, and the carbon - none of selenium interactions, may under compression, which, in the carbon skeleton, the selenium particles, and, It can provide excellent conductivity between carbon and selenium interactions, which are believed to help achieve the cycle performance observed at high C rates.

Immobilized selenium containing selenium and carbon produced according to the principles described herein may contain one or more of the following characteristics:

(A) The kinetic energy required for the selenium particles to separate from the immobilized selenium is ≧ 9.5 kJ / mol, ≧ 9.7 kJ / mol, ≧ 9.9 kJ / mol, ≧ 10.1 kJ / mol, ≧ 10 It can be .3 kJ / mol or ≧ 10.5 kJ / mol.

(B) The temperatures required for the selenium particles to separate from the immobilized selenium are ≧ 490 ° C, ≧ 500 ° C, ≧ 510 ° C, ≧ 520 ° C, ≧ 530 ° C, ≧ 540 ° C, ≧ 550 ° C, or ≧ 560. Can be ° C.

(C) Carbon has a surface area of ≧ 500 m ² / g, ≧ 600 m ² / g, ≧ 700 m ² / g, ≧ 800 m ² / g, ≧ 900 m ² / g, or ≧ 1,000 m ² / g (20 angstroms). Can have less than (for pores).

(D) Carbon has a surface area of ≤20%, ≤15%, ≤10%, ≤5%, ≤3%, ≤2%, ≤1% (pores between 20 angstroms and 1000 angstroms). ) Can have.

(E) Carbon and / or selenium may be under compression (compressed state). The advantage of immobilized selenium when carbon and / or selenium is under compression over the carbon-selenium system when carbon and / or selenium is not under compression is improved electron flow, reduced resistance to electron flow, Alternatively, both can be included, which facilitates the supply of electrons from the selenium anion and to selenium during charging and discharging of a secondary battery having a cathode composed of immobilized selenium.

(F) In order for selenium to withdraw from the immobilized Se-C complex system, the immobilized selenium contains a selenium having a higher activation energy than the relatively high activation energy in the conventional (non-immobilized) selenium. be able to. In one example, according to ASTM method E1641-16, the activation energy in non-immobilized selenium (Se-Super P complex system) was measured to be 92 kJ / mol. In contrast, in one example, the activation energy of selenium in immobilized selenium containing selenium and carbon is ≧ 95 kJ / mol, ≧ 98 kJ / mol, ≧ 101 kJ / mol, ≧ 104 kJ / mol, ≧ 107 kJ / mol, or , ≧ 110 kJ / mol. In another example, the activation energy of selenium in immobilized selenium containing selenium and carbon is ≧ 3%, ≧ 6%, ≧ 9%, ≧ 9 than the activation energy of selenium in the Se-Super P composite. It may be 12%, ≧ 15%, or ≧ 18% higher.

(G) Immobilized selenium can contain selenium having a higher collision frequency than non-immobilized selenium. In one example, the collision frequency of the non-immobilized selenium according ATSM method E1641-16, was measured to be 2.27 × 10 ^5. In contrast, in one example, the collision frequency of selenium in immobilized selenium containing selenium and ^{carbon, ≧ 2.5 × 10 5, ≧} 3.0 × 10 5, ≧ 3.5 × 10 5, ≧ 4. ^{0 × 10 5, ≧ 4.5 ×} 10 5, ≧ 5.0 × 10 5, ≧ 5.5 × 10 5, ≧ 6.0 × 10 5, or ≧ 8.0 × 10 ⁵ and is likely is there. Immobilized selenium is more than ≧ 10%, ≧ 30%, ≧ 50%, ≧ 80%, ≧ 100%, ≧ 130%, ≧ 150%, ≧ 180%, than non-immobilized selenium in Se-C composite. Alternatively, it may have a collision frequency of ≥200%.

(H) The immobilized selenium is the rate constant of non-fixed / conventional selenium of ≦ 1/5, ≦ 1/10, ≦ 1/50, ≦ 1/100, ≦ 1/500, or ≦ 1/1000. Can include selenium having a rate constant of. In one example, immobilized ^{selenium, ≦ 1 × 10 -10, ≦} 5 × 10 -11, ≦ 1 × 10 -11, ≦ 5 × 10 -12, or, ≦ 5 × ^{10 -13} rate constant (50 ° C. ) Can be included.

In the case of the carbon and / or selenium of the immobilized selenium under compression, the D-band and / or G-in the Raman spectrum of the Sp ² CC bond of the carbon of the immobilized selenium (or the carbon skeleton defined by the carbon above). The band may show a red (positive) shift from the carbon source, eg, ≧ 1 cm ^-1 , ≧ 2 cm ^-1 , ≧ 3 cm ^-1 , ≧ 4 cm ^-1 , or ≧ 5 cm ^-1 .

For carbon and / or selenium immobilization selenium in under compression, selenium, from the Raman peak of pure selenium (235 cm ^-1), for ^{example, ≧ 4cm -1, ≧ 6cm -1} , ≧ 8cm -1, ≧ 10cm - ^It may have a red (positive) shift of ¹ , ≧ 12 cm- ¹ , ≧ 14 cm- ¹ , or ≧ 16 cm- ¹ , suggesting compression in selenium particles.

The immobilized selenium may be elemental selenium and / or compound selenium.

Immobilized selenium, including selenium and carbon, is one or more additional elements from Group 6 of the Periodic Table (hereinafter "additional G6 elements"), including, but not limited to, sulfur and / or tellurium. May be doped with. The doping amount (dopant level) may range from as low as 100 mass ppm to as high as 85 mass% of the total mass of the immobilized selenium. In one example, the immobilized selenium can contain 15% to 70% carbon, 30% to 85% selenium, and optionally additional G6 elements. In one example, immobilized selenium can contain a mixture of (1) 15% to 70% carbon and (2) 30% to 85% selenium, plus additional G6 elements. In a mixture containing selenium + additional G6 element, the additional G6 element can make up 0.1% to 99% of the mixture and selenium can make up 1% to 99.9% of the mixture. it can. However, these ranges of selenium + additional G6 elements should not be construed in a limited sense.

Immobilized selenium is ≧ 5% selenium, ≧ 10% selenium, ≧ 20% selenium, ≧ 30%, ≧ 40% selenium, ≧ 50% selenium, ≧ 60% selenium, or ≧ 70%. Selenium, or more selenium.

The immobilized selenium may optionally contain other elements such as sulfur, tellurium and the like.

The immobilized selenium may be Raman-inactive or Raman-active. For Raman activity, immobilized selenium may have Raman relative peak intensities at 255 ± 25 cm ^-1 , 255 ± 15 cm ^-1 , or 255 ± 10 cm ^-1 .

Immobilized selenium can include selenium having a Raman relative peak intensity of ≧ 0.1%, ≧ 0.5%, ≧ 1%, ≧ 3%, or ≧ 5%, as described herein by Raman. Relative peak intensity is defined as the area of the Raman peak at 255 cm ^-1 with respect to the area of the D-band peak in the carbon Raman spectrum.

Carbon containing immobilized selenium can serve as a carbon backbone for the immobilization of selenium. Carbon backbone has a Raman D- band located 1365 ± 100 cm ^-1, and a Raman G- band located 1589 ± 100cm ^-1, Sp ² - carbon - may have carbon bonds, 1365 ± may have a G- band located D- band and 1589 ± 70cm ^-1 located 70cm ^-1, located D- band and 1589 ± 50 cm ^-1 is located in 1365 ± 50 cm ^-1 G - it may have a band may have a G- band located D- band and 1589 ± 30 cm ^-1 is located in 1365 ± 30 cm ^-1, or located in 1365 ± 20 cm ^-1 It may have a D-band and a G-band located at 1589 ± 20 cm ^-1 .

Carbon immobilization selenium, Sp ² carbon having a Raman peak, wherein the D- band and G- band - can include carbon bonds. The area ratio of the D-band to the G-band may be in the range 0.01 to 100, 0.1 to 50, or 0.2 to 20.

Carbon immobilization selenium, Sp ² carbon having a Raman peak, wherein the D- band and G- band - can include carbon bonds. Each of the D-band and G-band can shift to higher wavenumbers ≥ 1 cm ^-1 , ≥ 2 cm ^-1 , or higher.

The carbon of the immobilized selenium may be doped with one or more other elements of the Periodic Table.

The carbon of the immobilized selenium may be porous. The pore size distribution of the carbon skeleton may range between 1 angstrom and a few microns. The pore size distribution is between 1 angstrom and 1000 angstrom, between 1 angstrom and 100 angstrom, between 1 angstrom and 50 angstrom, between 1 angstrom and 30 angstrom, or between 1 angstrom and 20 angstrom. It may have at least one peak located in between. The porosity of the carbon skeleton may have a pore size distribution with more than one peak within the aforementioned range.

The carbon of the immobilized selenium is between 0.01 mL / g and 5 mL / g, between 0.01 mL / g and 3 mL / g, between 0.03 mL / g and 2.5 mL / g, or Pore volumes between 0.05 mL / g and 2.0 mL / g may be included.

The carbon of the immobilized selenium has a pore volume of 30%,> 40%,> 50%,> 60%,> 70%, or> 80% of the total measurable pore volume (<100 angstroms, < It may include 50 angstroms, <30 angstroms, or <20 angstroms with a pore size).

The carbon content of the immobilized selenium is> 400m ² / g,> 500m ² / g,> 600m ² / g,> 700m ² / g,> 800m ² / g,> 900m ² / g, or> 1000m ² / g. May include the surface area of.

The carbon of the immobilized selenium may be amorphous and may have a wide peak centered on the d-spacing of about 5.2 angstroms.

The carbon of the immobilized selenium can be in any form, ie platelet-like, spherical, fibrous, needle-like, tubular, irregular, interconnected, aggregated, discrete, or any solid particle. It may be. Thrombotic, fibrous, needle-like, tubular, or certain forms with a given size aspect ratio can be advantageous to achieve better interparticle contact (various). It provides an improvement in conductivity (over all immobilized selenium made with different aspect ratios), which can be beneficial for electrochemical cell batteries such as rechargeable batteries.

The carbon of the immobilized selenium has a median particle size between 1-9 nanometers and 2 millimeters, between 1-9 nanometers and <1000 microns, or between 20 nanometers and 100 microns. It may have any particle size.

The selenium of the immobilized selenium may be amorphous as determined by, for example, X-ray diffraction. The diffraction peak of the immobilized selenium selenium, which can have a d-spacing of about 5.2 angstroms, may be weaker than the diffraction peak for the carbon backbone, eg 10% weaker, 20% weaker. It may be 30% weaker, or 40% weaker.

In one example, the method of producing immobilized selenium can include:
(A) A step of physically mixing carbon and selenium. Physical mixing includes ball mills (dry and wet), mortar and pestle mixing (dry or wet), jet mills, horizontal mills, grinding mills, high shear mixing in slurries, normal slurry mixing with blades, etc. Can be carried out by.
(B) The carbon and selenium physically mixed in step (a) can be heated at the melting temperature of selenium or a higher temperature. Heating of the carbon and selenium mixture can be carried out in the presence of an inert gas environment such as, but not limited to, argon, helium, nitrogen, or in an air or reaction environment.
(C) The step of homogenizing or blending the heated carbon and selenium, as required, to achieve selenium immobilization. as well as,
(D) Cooling the immobilized selenium in step (c) to ambient temperature or room temperature.

In another example, immobilized selenium can be made by dissolving selenium on carbon and then evaporating it. As the solvent for dissolving selenium, alcohol, ether, ester, ketone, hydrocarbon, halogenated hydrocarbon, nitrogen-containing compound, phosphorus-containing compound, sulfur-containing compound, water and the like can be used.

In another example, immobilized selenium can be made by melting selenium on carbon and then removing excess or excess non-immobilized selenium.

In one example, methods for producing immobilized selenium include:
(A) A step of mixing selenium and carbon together in a dry state or a wet state.
(B) A step of drying the mixture of the step (a) at an increased temperature, if necessary.
(C) A step of pelletizing the dry mixture of the step (b), if necessary.
(D) A step of melting selenium into carbon to produce immobilized selenium.

Immobilized selenium can be used as a cathode material for secondary batteries. The cathode can include an inorganic binder or an organic binder. The inorganic binder may be a natural product such as CMC or a synthetic product such as SBR rubber latex. The cathode can include, for example, graphite-derived particles, graphene, carbon nanotubes, carbon nanosheets, carbon black, and other optional conductivity accelerators. Finally, the cathode can include a current collector such as, for example, aluminum foil, copper foil, carbon foil, carbon fiber, or other metal foil.

The method for producing a cathode includes applying an immobilized selenium-containing slurry onto a current collector and then drying the current collector after applying the slurry (for example, air drying, oven drying, vacuum oven drying, etc.). Can be done. Immobilized selenium can be dispersed in a slurry that can be prepared by a high shear mixer, a regular mixer, a planetary mixer, a double planetary mixer, a ball mill, a vertical attritor, a horizontal mill, or the like. The slurry can then be applied onto the current collector and then dried in air or in vacuum. Next, the cathode after coating can be pressurized or roller milled (or calendared) prior to use in a secondary battery.

A secondary battery can be made using the immobilized selenium described herein. The secondary battery can include a cathode containing immobilized selenium, an anode, and a separator that separates the anode and the cathode. The anode, cathode, and separator can be immersed in an electrolyte such as LiPF6. The anode may be composed of lithium, sodium, silicon, graphite, magnesium, tin and the like.

The separator may be composed of an organic separator, an inorganic separator, or a solid electrolyte separator. The organic separator can include, for example, polymers such as polyethylene, polypropylene, polyester, halogenated polymers, polyethers, polyketones and the like. The inorganic separator may include glass fiber or quartz fiber, or a solid electrolyte separator.

The electrolyte can contain lithium salts, sodium salts, or other salts of the IA, IIA, and IIIA groups in organic solvents. The organic solvent can include an organic carbonate compound, an ether, an alcohol, an ester, a hydrocarbon, a halogenated hydrocarbon, a lithium-containing solvent and the like.

The secondary battery can be used in electronic devices (electronics), electric vehicles or hybrid vehicles, industrial applications, military applications such as unmanned aircraft, aerospace applications, marine applications, and the like.

The secondary battery has ≧ 400 mAh / g per selenium activity amount, ≧ 450 mAh / g per selenium activity amount, ≧ 500 mAh / g per selenium activity amount, ≧ 550 mAh / g per selenium activity amount, or ≧ 600 mAh / g per selenium activity amount. It may have an electrochemical capacity of g.

The secondary battery can undergo an electrochemical cycle such as ≧ 50 cycle, ≧ 75 cycle, ≧ 100 cycle, ≧ 200 cycle.

Secondary batteries charge and charge at 0.1C, 0.2C, 0.5C, 1C, 1.5C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, or faster. / Or may be discharged.

The secondary battery has a high C rate charge / discharge cycle (0.1C: 5 cycles, 0.2C: 5 cycles, 0.5C: 5 cycles, 1C: 5 cycles, 2C: 5 cycles, 5C: 5 cycles, 10C. After 5 cycles), at a cycle rate of 0.1C,> 30%,> 40%,> 50%,> 60%,> 70%, or> 80% of the specific capacitance of the second discharge. The battery specific capacity can be maintained.

The secondary battery can have a coulombic efficiency of ≧ 50%, ≧ 60%, ≧ 70%, ≧ 80%, ≧ 90%, or about 100%. The Coulombic efficiency of a battery is defined as follows.

Charge the secondary battery at 0.1C, 0.2C, 0.5C, 1C, 1.5C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, or faster C rate. be able to. The C rate is the degree of rate (speed) when the battery is discharged with respect to the maximum capacity. For example, 1C rate means that the discharge current discharges the entire battery in 1 hour. For example, for a battery with a capacity of 100 amps-hrs, this is equal to a discharge current of 100 amps. It can be said that the 5C rate of this same battery is 500 amperes and the 0.5C rate is 50 amperes.

The cathode of the secondary battery can contain one or more elements of the oxygen group (chalcogen group) such as selenium, sulfur, tellurium, and oxygen.

The anode of the secondary battery can contain at least one element of an alkali metal, an alkaline earth metal, and a Group IIIA metal.

The separator of the secondary battery may include an organic separator or an inorganic separator.

The electrolytic solution of the secondary battery can contain at least one element of an alkali metal, an alkaline earth metal, and a group IIIA metal, and the solvent of the electrolytic solution is a carbonate-based, ether-based, or ester-based organic. It can contain a solvent.

The secondary battery can have a specific capacity of ≧ 400 mAh / g, ≧ 450 mAh / g, ≧ 500 mAh / g, ≧ 550 mAh / g, or ≧ 600 mAh / g.

The secondary battery can undergo an electrochemical cycle such as ≧ 50 cycle, ≧ 75 cycle, ≧ 100 cycle, ≧ 200 cycle.

The secondary battery has a high C rate charge / discharge cycle (0.1C: 5 cycles, 0.2C: 5 cycles, 0.5C: 5 cycles, 1C: 5 cycles, 2C: 5 cycles, 5C: 5 cycles, and so on. After 5 cycles at 10C), at a cycle rate of 0.1C,> 30%,> 40%,> 50%,> 60%,> 70%, or> 80% of the specific capacitance of the second discharge. Can have a specific capacity of.

The secondary battery can have a coulombic efficiency of ≧ 50%, ≧ 60%, ≧ 70%, ≧ 80%, or ≧ 90%.

Complexes containing selenium and carbon are also disclosed, and the above complexes may have a platelet shape having an aspect ratio of ≧ 1, ≧ 2, ≧ 5, ≧ 10, or ≧ 20.

The selenium in the complex may be amorphous, as determined, for example, by X-ray diffraction. The diffraction peaks of selenium can have a d-spacing of about 5.2 angstroms and are weaker than the diffraction peaks in the carbon skeleton, eg 10% weaker, 20% weaker, 30% weaker, or 40% weaker than the carbon skeleton. It may be weak.

In one example, the method of producing the composite material includes:
(A) A step of physically mixing carbon and selenium. Physical mixing is carried out by ball mill (dry and wet), mortar and pestle mixing (dry or wet), jet mill, horizontal mill, grinding mill, high shear mixing in slurry, normal slurry mixing with blades, etc. it can.
(B) The physically mixed carbon and selenium of step (a) can be heated to the melting point temperature or higher temperature of selenium, which heating is the presence of an inert gas environment such as argon, helium, nitrogen, etc. It can be carried out underneath or in the air or in a reactive environment. as well as,
(C) The heated carbon and selenium from step (b) can be homogenized or blended to aid in achieving selenium immobilization.

In another example, the composite can be made by dissolving selenium on carbon and then evaporating it. Examples of the solvent for dissolving selenium include alcohols, ethers, esters, ketones, hydrocarbons, halogenated hydrocarbons, nitrogen-containing compounds, phosphorus-containing compounds, sulfur-containing compounds, water and the like.

The complex can be made by melting the selenium on (or in) the carbon and then removing the excess or excess unimmobilized selenium.

In one example, the method of producing the composite material includes:
(A) A step of mixing selenium and carbon together in a dry state or a wet state.
(B) A step of drying the mixture of the step (a) at an increased temperature, if necessary.
(C) A step of pelletizing the dry mixture of the step (b) as needed.
(D) A step of melting selenium in carbon to produce immobilized selenium.

The composite material can be used as a cathode material for the cathode of a secondary battery. The cathode can include an inorganic binder or an organic binder. The inorganic binder may be a natural product such as CMC or a synthetic product such as SBR rubber latex. The cathode can contain, if desired, a conductivity accelerator such as graphite-derived particles, graphene, carbon nanotubes, carbon nanosheets, carbon black. Finally, the cathode can include a current collector such as, for example, an aluminum foil, a copper foil, a carbon foil, carbon fibers, or other metal foil.

The method for producing the cathode is to apply the immobilized selenium-containing slurry on the current collector, and then dry the current collector after applying the slurry (for example, air drying, oven drying, vacuum oven drying, etc.). Can include. Immobilized selenium can be dispersed in a slurry that can be produced by a high shear mixer, a regular mixer, a planetary mixer, a double planetary mixer, a ball mill, a vertical attritor, a horizontal mill, or the like. The slurry can then be applied onto the current collector and then dried in room air or in vacuum. The coated cathode can be pressurized or roller milled (or calendared) prior to use in a secondary battery.

A secondary battery can be manufactured using the above composite material. The secondary battery can be charged at 0.1C, 0.2C, 0.5C, 1C, 1.5C, 2C, 3C, 4C, 5C, 6C, 7C, 8C, 9C, 10C, or faster.

Example 13: Manufacture of sulfur-doped immobilized selenium, electrodes, and batteries thereof.
In the synthesis of sulfur-doped immobilized selenium detailed in Table 4, according to the principles and procedures described in Example 10, 5 atomic% selenium, 20 atomic% selenium, 35 atomic% selenium, and 50 atomic selenium. % Was replaced by sulfur respectively. A sample of sulfur-doped immobilized selenium was synthesized using a carbon skeleton prepared according to the principles and procedures described in Example 9.

Next, using the sulfur-doped immobilized selenium sample thus produced, a large number of cathodes 4 containing sulfur-doped immobilized selenium are produced according to the principle and procedure described in Example 11 relating to the immobilized selenium. did.

Subsequently, using the cathode containing sulfur-doped immobilized selenium thus produced in this example, a coin-type cell battery was produced according to the principle and procedure described in Example 12.

The coin-operated cell battery assembled in this example was tested on the battery tester described in Example 12 at charge / discharge cycle rates of 0.1C and 1C according to the same test protocol described in Example 12. ..

FIG. 18 shows the results of the electrochemical cycle at 0.1 C for a coil battery containing a cathode composed of a sulfur-doped immobilized selenium cathode prepared from a sulfur-doped immobilized selenium sample (Se50S50 in Table 4). Here, the second cycle discharge capacity is 821 mAh / g (which is considered good), and the steady-state Coulomb efficiency is ≧ 95%, typically ≧ 98% (which is considered good). Or it is as high as 100%.

Assuming that selenium has a stoichiometric specific volume of 675 mAh / g at a 0.1 C cycle rate, the sulfur specific volume would be estimated to be about 1,178 mAh / g (which is considered good for sulfur). .. Coulomb efficiencies ≧ 95%, ≧ 98%, or as high as 100% indicate that significant amounts of sulfur do not reciprocate between the cathode and anode. Sulfur species in sulfur-doped immobilized selenium batteries work well in electrolytes containing carbonate. Typically, sulfur is not expected to work well in Li-S batteries that have carbonate as the electrolyte. Conventional Li-S batteries typically use an ether-based electrolyte. The carbonate-based electrolyte is typically used in this lithium-ion battery. Carbonate-based electrolytes are more economical and more widely used in the market than ether-based electrolytes.

FIG. 19 shows the electrochemical cycle results at a 1C cycle rate for a coil cell battery containing a cathode composed of a sulfur-doped immobilized selenium cathode prepared from a sulfur-doped immobilized selenium sample (Se50S50 in Table 4). Here, the second cycle discharge capacity is 724 mAh / g, and the steady-state Coulomb efficiency is as high as ≧ 95%, typically ≧ 98%, or 100%.

Assuming that selenium has a specific volume of 625 mAh / g at a 1C cycle rate, the sulfur specific volume would be estimated to be about 966 mAh / g (also unexpected). Sulfur is an insulator and has very low electrical conductivity. Generally, Li-S batteries cannot cycle well at high cycle rates such as 1C rate.

As described above, when used as a cathode material for secondary batteries, sulfur-doped immobilized selenium overcomes two fundamental problems associated with Li-S batteries: the shuttle effect and the low cycle rate. By solving these two problems, a battery containing a cathode composed of sulfur-doped immobilized selenium can have a high energy density and a high power density in practical applications.

As described above, in one example, the sulfur-doped immobilized selenium system or the sulfur-doped immobilized selenium compound can be formed by a method including the following. (A) A step of mixing selenium, carbon, and sulfur to prepare a selenium-carbon-sulfur mixture. (B) A step of heating the mixture of step (a) to a temperature higher than the melting temperature of selenium. And (c) a step of cooling the heated mixture of step (b) to ambient temperature or room temperature, thereby producing a sulfur-doped immobilized selenium compound.

The sulfur-doped immobilized selenium compound in step (c) can contain selenium and sulfur in the carbon skeleton.

Step (a) can be carried out in a dry state or a wet state.

Step (b) can include homogenizing or blending the mixture.

Step (a) can include forming a selenium-carbon-sulfur mixture into the body (form). Step (b) can include heating the body to a temperature higher than the melting temperature of selenium. Step (c) can include cooling the body to ambient temperature or room temperature or making it coolable.

Step (b) can include heating the mixture for such a time that selenium, carbon and sulfur can react completely or partially.

In another example, the method for producing a sulfur-doped immobilized selenium system or a sulfur-doped immobilized selenium compound is (a) a step of forming a carbon skeleton. (B) A step of melting selenium and sulfur in a carbon skeleton.

In another example, the method for producing a sulfur-doped immobilized selenium system or a sulfur-doped immobilized selenium compound is, after (a) a step of mixing selenium, carbon and sulfur, and (b) step (a). The step of dissolving selenium and sulfur in carbon to form a sulfur-doped immobilized selenium system or a sulfur-doped immobilized selenium compound can be included.

The solvent for dissolving selenium and sulfur can be alcohol, ether, ester, ketone, hydrocarbon, halogenated hydrocarbon, nitrogen-containing compound, phosphorus-containing compound, sulfur-containing compound, or water. A solvent may be added to one or more of selenium, sulfur, or carbon before step (a), during step (a), or during step (b).

The method can further include (c) removing excess non-immobilized selenium, non-immobilized sulfur, or both from the sulfur-doped immobilized selenium system or the sulfur-doped immobilized selenium compound.

A cathode composed of sulfur-doped immobilized selenium arranged on a conductive substrate, a separator arranged in direct contact with the conductive substrate and in contact with sulfur-doped immobilized selenium, and separated from the cathode by a separator. Secondary batteries, including the anode, are also disclosed.

The secondary battery can further include an anode separated from the separator by lithium. In one example, lithium can be in the form of a lithium foil.

The secondary battery can further include a cathode, a separator, an anode, and lithium immersed in an electrolyte.

In a secondary battery, the sulfur-doped immobilized selenium can include a selenium-carbon-sulfur mixture in which selenium and sulfur are melted into carbon.

In the secondary battery, the separator may be made of an organic material, an inorganic material, or a solid electrolyte.

The secondary battery can have a Coulomb efficiency of ≧ 95%.

These examples are described with reference to the accompanying drawings. If you read and understand the above example, you will make modifications and changes to other examples. Therefore, the above example should not be construed as limiting this disclosure.

Claims (21)

(A) A step of mixing selenium and carbon to form a selenium-carbon mixture, and
(B) A step of heating the mixture of the step (a) to a temperature higher than the melting temperature of selenium, and
By cooling the heated mixture of step (c) (b) to ambient or room temperature, see contains a step, the forming an immobilized selenium or immobilized selenium body comprising selenium to a carbon skeleton in,
The activation energy for releasing the selenium particles from the immobilized selenium system or the immobilized selenium body is ≧ 95 kJ / mol, and the immobilized selenium system or the immobilized selenium body is in the middle of 520 ° C. or higher. A method for producing an immobilized selenium system or an immobilized selenium body having a mass loss temperature . The carbon skeleton, under compression is Sp ² carbon - containing carbon bond and the fixing selenium of step (c), selenium is under compression - comprising selenium binding method of claim 1. The method of claim 1, wherein step (a) is performed in a dry or wet state. The method of claim 1, wherein step (b) further comprises homogenizing or blending the mixture. Step (a) involves forming the selenium-carbon mixture into a form.
Step (b) involves heating the feature to a temperature higher than the melting temperature of the selenium.
The method of claim 1, wherein step (c) comprises cooling the feature to ambient temperature or room temperature. The method of claim 1, wherein step (b) comprises heating the mixture for a time sufficient for the selenium to react completely or partially with the carbon. A method for producing an immobilized selenium system or an immobilized selenium body.
(A) Step of forming carbon skeleton and
(B) look including a step of forming the immobilized selenium or immobilized selenium body comprising selenium in the carbon skeleton by melting the selenium in the carbon skeleton,
The activation energy for releasing the selenium particles from the immobilized selenium system or the immobilized selenium compound is ≧ 95 kJ / mol, and the immobilized selenium system or the immobilized selenium compound is intermediate at 520 ° C. or higher. A method having a mass loss temperature . An immobilized selenium body containing selenium in a carbon skeleton body, the activation energy for releasing selenium particles from the immobilized selenium body is ≧ 95 kJ / mol, and an intermediate mass loss temperature of 520 ° C. or higher is achieved. Immobilized selenium body which has at least one of the following.
(A) The kinetic energy for the selenium particles to separate from the immobilized selenium body is ≧ 9.5 kJ / mol.
(B) The temperature for the selenium particles to separate from the immobilized selenium body is ≧ 490 ° C.
(C) The carbon contains pores of less than 20 angstroms, and for the pores of less than 20 angstroms, the carbon has a surface area of ≥400 m ² / g.
(D) The carbon comprises pores between 20 angstroms and 1000 angstroms, and for the pores between 20 angstroms and 1000 angstroms, the carbon has a surface area of ≦ 20% of the total surface area.
(E) The carbon, the selenium, or both are under compression.
(F) the collision frequency of the selenium in the immobilized selenium body is ≧ 2.5 × 10 ^5. as well as,
(G) At 50 ° C., the immobilized selenium body has a rate constant of ≦ 1 × 10 ⁻¹⁰ . The immobilized selenium according to claim 8 , wherein the selenium is elemental selenium, compound selenium, or both. In addition to selenium and carbon, the immobilized selenium compound contains at least one other element from Group 6 of the periodic table at 100 ppm with respect to the mass of the immobilized selenium compound, and the total of the immobilized selenium compound. The immobilized selenium body according to claim 8 , which comprises at a concentration between 85% by mass. The selenium contains interfacial selenium and
The kinetic energy for selenium particles detached from the interface selenide immobilized selenium body, at a temperature of ≧ 660 ℃, ≧ 11,635 are joules / mole, immobilization selenium of claim 8. The immobilized selenium body according to claim 8 , wherein the immobilized selenium body contains ≧ 5% selenium. The immobilized selenium body according to claim 8 , wherein the immobilized selenium body has a Raman peak intensity of 255 ± 25 cm ^-1 . The carbon of the immobilized selenium body defines the carbon skeleton and
The carbon skeleton, Sp 2 with Raman peak of D- band and G- Band ^- carbon - has a carbon bond,
The immobilized selenium body according to claim 8 , wherein the area ratio of the D-band to the G-band is between 0.01 and 100. The carbon skeleton includes a Raman D- band located 1365 ± 100 cm ^-1, and a Raman G- band located 1589 ± 100 cm ^-1, immobilization selenium of claim 14. A method for producing a sulfur-doped immobilized selenium system or a sulfur-doped immobilized selenium compound.
(A) A step of mixing selenium, carbon, and sulfur to form a selenium-carbon-sulfur mixture, and
(B) A step of heating the mixture in step (a) to a temperature higher than the melting temperature of selenium, and
(C) A step of forming a sulfur-doped immobilized selenium system containing selenium and sulfur in a carbon skeleton or a sulfur-doped immobilized selenium body by cooling the heated mixture of step (b) to an ambient temperature or room temperature. and, only including,
The activation energy for releasing the selenium particles from the sulfur-doped immobilized selenium system or the sulfur-doped immobilized selenium compound is ≧ 95 kJ / mol, and the sulfur-doped immobilized selenium system or the sulfur-doped immobilized A method in which the selenium body has an intermediate mass loss temperature of 520 ° C. or higher . 16. The method of claim 16 , wherein step (a) is performed under dry or wet conditions. 16. The method of claim 16 , wherein step (b) further comprises homogenizing or blending the mixture. Step (a) involves forming the selenium-carbon-sulfur mixture into a form.
Step (b) includes heating the feature to a temperature higher than the melting temperature of selenium, and
16. The method of claim 16 , wherein step (c) comprises cooling the feature to ambient temperature or room temperature. 16. The method of claim 16 , wherein step (b) comprises heating the mixture for a time sufficient for the selenium, the carbon and the sulfur to react completely or partially. A method for producing a sulfur-doped immobilized selenium system or a sulfur-doped immobilized selenium compound.
(A) Step of forming carbon skeleton and
(B) look including a step of forming a sulfur-doped immobilized selenium or sulfur doped immobilized selenium body by melting the selenium and sulfur in the carbon skeleton,
The activation energy for releasing the selenium particles from the sulfur-doped immobilized selenium system or the sulfur-doped immobilized selenium compound is ≧ 95 kJ / mol, and the sulfur-doped immobilized selenium system or the sulfur-doped immobilized A method in which the selenium body has an intermediate mass loss temperature of 520 ° C. or higher .