Disclosure of Invention
The invention discloses a positive electrode material for a solid electrolyte molten lithium metal battery, which comprises an active metal material, wherein the active metal material is selected from any one or more metal simple substances or alloys of the metal simple substances in aluminum, titanium, chromium, manganese, iron, nickel, copper, zinc, cadmium, lead and bismuth, the active lithium source is selected from one or a mixture of LiF and LiCl, and a conductive additive and a lithium ion conductive additive. The active metal material, lithium source, conductive additive and lithium ion conductive additive contained in the positive electrode material are all commonly used powder substances. The materials have the advantages of wide sources, easy acquisition, no pollution to the environment, convenient transportation, low price and the like.
A positive electrode material for a solid electrolyte molten lithium metal battery, the positive electrode material consisting of an active metal, an active lithium source, and a conductive additive and a lithium ion conducting additive, wherein the active lithium source is selected from one or a mixture of lithium halides.
Further, the positive electrode composed of the active metal material has a theoretical mass energy density of more than 500Wh/kg, or more than 700Wh/kg, or more than 1000Wh/kg, or more than 1200Wh/kg when only active materials are calculated; the theoretical volumetric energy density is greater than 1500Wh/L, or greater than 2000Wh/L, or greater than 3000Wh/L, or greater than 5000Wh/L; the energy cost of the battery is lower than 600 yuan/kWh; the capacity utilization of the battery is greater than 60%, alternatively greater than 70%, alternatively greater than 75%.
Further, the positive electrode material comprises an active metal material selected from any one or more metal simple substances or alloys of the metal simple substances of aluminum, titanium, chromium, manganese, iron, nickel, copper, zinc, cadmium, lead and bismuth.
Further, the active lithium source is selected from one or a mixture of LiF and LiCl.
Further, the conductive additive material has good conductivity at 200-400 ℃ and electronic conductivity>0.1S/m; has good chemical stability and oxidation potential higher than 2.5VvsLi + /Li。
Further, the conductive additive material is selected from one or more of graphite, carbon black, acetylene, amorphous carbon, carbon fiber, carbon nano tube, graphene, copper powder, copper mesh and foam copper, so as to construct a three-dimensional conductive sub-network.
Further, the lithium ion conductive additive material is inorganic salt or mixed salt, has a certain solubility to LiCl or LiF in a molten state, has a melting point lower than 400 ℃ and has an oxidative decomposition potential higher than 2.5VvsLi + /Li。
Further, the lithium ion conductive additive material is selected from LiAlCl 4 、NaAlCl 4 、LiCl-KCl、LiBr-KBr、LiI-CsI、LiCl-ZnCl 2 、NaCl-ZnCl 2 、KCl-ZnCl 2 Or LiBr-KBr-CsBr for transporting Li + 。
When preparing the positive electrode material, firstly preparing the lithium ion conducting additive (such as LiCl-KCl mixed salt), and then weighing the lithium ion conducting additive as a whole according to the proportion and adding the lithium ion conducting additive into the positive electrode material.
Further, the positive electrode material consists of active metal M (M is any one or more metal simple substances or alloys of the metal simple substances of aluminum, titanium, chromium, manganese, iron, nickel, copper, zinc, cadmium, lead and bismuth), lithium source LiX (LiX is LiF, liCl or a mixture of the LiF and the LiCl), a conductive additive and a lithium ion conductive additive.
Further, the molar ratio of active metal to lithium source (lithium salt) is 1 (1-4), which may be, for example, 1:1, 1:1.2, 1:1.4, 1:1.6, 1:1.8, 1:2, 1:2.2, 1:2.4, 1:2.6, 1:2.8, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, or 1:4.
Further, the mass ratio of the lithium source (lithium salt) to the electron-conducting additive is (0.1-10): 1, for example, may be 0.1:1, 0.2:1, 0.5:1, 1:1, 2:1, 5:1, 7:1, 7.5:1, 8:1, 8.5:1, 9:1, 9.5:1, or 10:1.
Further, the mass ratio of the lithium source (lithium salt) to the ion conducting additive is 1 (0.1-5), for example, may be 1:0.1, 1:0.5, 1:1, 1:1.5, 1:2, 1:2.5, 1:3, 1:3.2, 1:3.4, 1:3.6, 1:3.8, 1:4, 1:4.5 or 1:5.
Wherein, the optimal molar ratio of the active metal to the lithium salt is 1:n, wherein n is the valence of metal ions generated by the active metal discharge; the optimal ratio of the lithium salt to the conductive additive is 5:1, and the optimal ratio of the lithium salt to the conductive additive is 1:1.5.
The positive electrode material has higher energy density, and theoretical mass energy density is more than 500Wh/kg, or more than 700Wh/kg, or more than 1000Wh/kg, or more than 1200Wh/kg, and theoretical volume energy density is more than 1500Wh/L, or more than 2000Wh/L, or more than 3000Wh/L, or more than 5000Wh/L.
The invention also provides a preparation method of the anode material, which comprises the step of ball milling the active metal, the active lithium source, the conductive additive and the lithium ion conductive additive to obtain the uniform anode material.
The invention also provides application of the positive electrode material in a solid electrolyte molten lithium metal battery, wherein the solid electrolyte molten lithium metal battery comprises a positive electrode, a negative electrode and a solid electrolyte.
Further, the solid electrolyte is an LLZTO ceramic tube.
The structure of a solid electrolyte molten lithium metal battery using the positive electrode material of the present invention is shown in fig. 1, and the solid electrolyte is a U-shaped ceramic tube.
The principle of the battery is as follows:
the positive electrode is densely filled outside the U-shaped ceramic tube by using the positive electrode material, the inside of the ceramic tube is used as the negative electrode of the battery, and the negative electrode is assembled in a discharge state without pre-filling metal Li.
In addition, the Li is led in the positive electrode material + Molten salt with transport Li + The positive electrode material always keeps close contact with the U-shaped ceramic tube during the charge and discharge process of the battery under the action of ions so as to facilitate Li + And (3) ion transmission.
When charged, M in the positive electrode loses n (n is 2,3 or 4) electrons to generate M n+ And with X in the positive electrode - Combining to generate MX n . At the same time, li in the positive electrode + Electrons are obtained in the negative electrode through the U-shaped ceramic tube, and elemental metal Li is generated.
During discharge, elemental Li metal in the anode loses electrons, and generated Li + X-is combined with LiX in the positive electrode through the U-shaped ceramic tube, and meanwhile M n+ N electrons are obtained, generating M.
Further, the reaction formula of the battery is:
positive electrode reaction: MX (MX) n +nLi + +ne→M+nLiX
Negative electrode reaction: nLi → nLi + +ne
Total reaction: MX (MX) n +nLi→M+nLiX
Further, the battery is operated at a temperature of 100-800 ℃ during charge-discharge cycles, preferably the battery is operated at a temperature of 200-400 ℃.
The invention has the following advantages:
(1) The anode material has no inflammable, explosive, volatile and gas-producing components and high safety.
(2) The positive electrode material has higher energy density, theoretical mass energy density is more than 500Wh/kg, and theoretical volume energy density is more than 1500Wh/L.
(3) The preparation process of the anode material is simple, the source of raw materials is wide, the anode material is cheaper, and the theoretical energy cost is lower than 600 yuan/kWh.
(4) The lithium ion passage and the electron passage in the positive electrode material are smooth, so that the active substances can fully react, and the capacity exertion rate is more than 60%.
Detailed Description
It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application, and the terminology used is for the purpose of describing particular embodiments only and is not intended to be limiting of exemplary embodiments based on the present application.
Some detailed embodiments of the present invention will be disclosed below, although examples of implementation are described in this disclosure, embodiments of the present invention are not limited to what has been shown. The disclosed embodiments are merely examples of what may be claimed as examples of what may be provided and other embodiments that are not shown and alternatives, modifications, equivalents, etc. may be included within the scope of the claims.
Example 1
0.87g of Zn simple substance powder, 1.12g of LiCl powder, copper powder accounting for 50 percent of the mass of LiCl, naCl-ZnCl accounting for 100 percent of the mass of LiCl 2 (NaCl 0.19g, znCl) 2 0.93 g) are put into a high-energy ball mill together, ball milling is uniform, and a uniform anode material is obtained.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. Li in molten ion-conducting additive when the battery is charged + Ions can pass through LLZTO ceramic electrolyte to reach the cathode and combine with electrons from an external circuit to form a Li cathode, and meanwhile Cl-reacts with Zn to generate ZnCl 2 And release electrons to the external circuit. The reverse process is carried out during discharge, and Li in the negative electrode loses electrons to form Li + ,Li + Returns to the positive electrode through the ceramic electrolyte.
Fig. 2 is a charge curve of a solid electrolyte molten lithium metal battery in example 1.
Example 2
1.12g of Zn simple substance powder, 1.46g of LiCl powder, graphite powder accounting for 20 percent of the mass of LiCl and LiAlCl accounting for 150 percent of the mass of LiCl are mixed 4 Putting the materials together into a high-energy ball mill, and uniformly ball-milling to obtain a uniform anode material.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. Li in molten ion-conducting additive when the battery is charged + Ions can pass through LLZTO ceramic electrolyte to reach the cathode and combine with electrons from an external circuit to form a Li cathode, and meanwhile Cl-reacts with Zn to generate ZnCl 2 And release electrons to the external circuit. The reverse process is carried out during discharge, and Li in the negative electrode loses electrons to form Li + ,Li + Returns to the positive electrode through the ceramic electrolyte.
Fig. 3 is a charge curve of a solid electrolyte molten lithium metal battery of example 2.
Example 3
0.72g of Ni simple substance powder, 1.04g of LiCl powder, carbon black powder accounting for 20 percent of the mass of LiCl and NaAlCl accounting for 250 percent of the mass of LiCl 4 Putting the materials together into a high-energy ball mill, and uniformly ball-milling to obtain a uniform anode material.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. Li in molten ion-conducting additive when the battery is charged + Ions will pass through LLZTO ceramic electrolyte to reach the anode and combine with electrons from the external circuit to form Li anode, while Cl-reacts with Ni to form NiCl 2 And release electrons to the external circuit. The reverse process is carried out during discharge, and Li in the negative electrode loses electrons to form Li + ,Li + Returns to the positive electrode through the ceramic electrolyte.
Fig. 4 is a charge curve of a solid electrolyte molten lithium metal battery in example 3.
Example 4
2.08g of Fe simple substance powder, 1.94g of LiF powder, 10 percent of graphite powder accounting for LiF mass and 150 percent of KCl-ZnCl accounting for LiF mass 2 (KCl 0.91g, znCl) 2 2.00 g) are put into a high-energy ball mill together, ball milling is uniform, and a uniform anode material is obtained.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. Li in molten ion-conducting additive when the battery is charged + Ions can pass through LLZTO ceramic electrolyte to reach the cathode and combine with electrons from an external circuit to form a Li cathode, and F-reacts with Fe to generate FeF 2 And release electrons to the external circuit. The reverse process is carried out during discharge, and Li in the negative electrode loses electrons to form Li + ,Li + Returns to the positive electrode through the ceramic electrolyte.
Fig. 5 is a discharge curve of the solid electrolyte molten lithium metal battery of example 4.
Table 1 product performance tables for examples 1-4
Comparative example 1:
0.87g of Zn simple substance powder, 1.12g of LiCl powder, copper powder accounting for 50 percent of the mass of LiCl, naCl-ZnCl accounting for 5 percent of the mass of LiCl 2 (NaCl 0.0095g, znCl) 2 0.0465 g) were put into a high-energy ball mill together, and ball-milled uniformly to obtain a uniform cathode material.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. The battery cannot be charged or discharged, and the capacity utilization rate is 0%.
Comparative example 2:
1.12g of Zn simple substance powder, 1.46g of LiCl powder, 1400% of graphite powder based on the mass of LiCl and 150% of LiAlCl based on the mass of LiCl 4 Putting the materials together into a high-energy ball mill, and uniformly ball-milling to obtain a uniform anode material.
The positive electrode is made of positive electrode material, the negative electrode is only provided with a current collector, and an LLZTO ceramic tube is selected as a solid electrolyte. The battery can be charged and discharged, but the capacity utilization rate is only 9.47%.