TWI264141B - Modified material for anode of lithium secondary battery and manufacturing method thereof - Google Patents

Abstract

In a modified material for an anode of a lithium secondary battery and its manufacture method, zinc oxide (ZnO) is coated on the surface of a lithium cobalt oxide (LiCoO2) anode of the secondary battery. The method dissolves soluble zinc salt into methanol (CH3OH) and mixes lithium cobalt oxide (LiCoO2) into the solution. After separation, drying and calcination, a modified lithium cobalt oxide (LiCoO2) is obtained, and such lithium cobalt oxide (LiCoO2) can be used as the material for the anode of the secondary battery.

Description

1264141

V. Description of the invention (1) [Technical field to which the invention pertains]

The present invention relates to a surface-A preparation method, and more particularly to a modified material using a positive electrode and a charge and discharge effect thereof. The backup battery has a positive battery to make it more [previous technology] mobile phones, laptops, video cameras, people's modern life and work in the world... cameras, electronic products have become their own, you can see the South Technology consumer goods . As soon as we have a brother, let’s take care of our power supply. In fact, the application range of the clock battery is no stranger to all fields, and is used by humans. The battery is entering the human society. The 4 lithium battery is divided into one battery and the second-class power consumption. The battery is currently in the camera pool, while in the camera, digital: the machine is not rechargeable. In the larger electronic products with lithium batteries, power-consuming sub-batteries such as mobile phones and notebook computers are used. Compared with the former, the advantage of lithium ion 2:::, lithium battery 'that is lithium long' clock ion battery is that the amount of V-hydrogen battery and open circuit (4) 2V voltage 乂 (:; 3. 6 (25 times the recording battery of nickel-cadmium secondary battery), low discharge capacity and low discharge rate (less than 8α / / B \ 疋 nickel 虱 - 1.5 times of secondary battery), 40% of self-battery / month), | 30% of the battery, and more than NiMH. No right "can be long-lived (can pass and charge the number of times can reach thousands of outstanding excellent ^ recall effect is also a popular ion-chain battery charging do not have to worry about whether the power has been used up. Electricity Page 5 1264141

The ion battery was developed and commercialized by SONY Japan in 990. 'The emergence of it is a step in the history of secondary batteries. In the following 10 years, its commercialization process has been achieved. Flying suddenly = flying development. Compared with other secondary batteries, its working principle is relatively simple. It is called lithium ion battery because it is in the form of ions in either the positive and negative electrodes or the battery separator. The anode of the ion battery is a carbon material such as graphite; the positive electrode is a transition metal oxide containing lithium, such as LiCo 2 , LiMri 2 4 , etc.; and the electrolyte is a solution containing a lithium salt. During operation (charging or discharging) of lithium ion batteries, lithium ions are orientated in the positive and negative electrodes and the electrolyte membrane. During charging, lithium ions are driven out of the positive electrode material by the electric field, and are inserted into the negative electrode through the electrolyte. When discharging, the process is just the opposite, that is, lithium ions return to the positive electrode, and electrons pass through and supply power to the used electronic products. 2. In the above, it is known that lithium ion secondary batteries have considerable market demand. The positive and negative electrodes and electrolyte materials have also been extensively studied. Lithium cobalt oxide (L i C〇02 ), which is a layered structure in its positive electrode, is most widely used because of its high capacitance and good cycleability. When the material is charged and discharged at a cut-off voltage of 4.2 V, the structure stability and cycle are good. However, the maximum capacitance that can be reached at this time is about 140 mAh/g, which is only half of the theoretical capacitance value of 274 mAh/g. Increasing the charge and discharge potential can theoretically increase the capacitance greatly. However, at high cut-off voltages, the structural changes of lithium cobalt oxide (Li C〇02) and the problem of oxidation and dissolution of the initial ions are severe, resulting in capacitance loss (Capacity Loss). ) Very fast. To solve this problem, many studies have been proposed

Page 6 1264141 V. Description of the invention (3) Adding other metal ions (such as aluminum (A1), magnesium (Mg), manganese (Μη), copper (Cu), iron (Fe), zinc (in aluminum oxide) The method of Zn), etc., is expected to stabilize the structure of lithium cobalt oxide (L i C〇02) during charge and discharge, but the effect is not good. Recently, a surface modification method has been proposed to coat a surface of a lithium cobalt oxide with a metal oxide such as alumina (A12〇3), magnesium oxide (MgO), tin oxide (Sn02), or aluminum phosphate (Α1Ρ〇). 4)...etc., to suppress the chemical reaction between the positive electrode material and the electrolyte during the charge and discharge process, but the above materials have the defects of material preparation or difficult process control. SUMMARY OF THE INVENTION The main object of the present invention is to provide a modification method which can effectively improve the electrochemical properties of the hour oxide, and increase the cycle of lithium cobalt oxide at a high charge and discharge potential (for example, 4 · 5 V). The modification method is effective and applicable to the process of commercial mass production. Another object of the present invention is to provide a modified material which is effective for enhancing the electrochemical properties of lithium cobalt oxide. The modified material of the positive electrode of the lithium secondary battery disclosed in the present invention is characterized in that the positive electrode of the secondary battery is a chain drill oxide (L i C 〇〇 2), and a zinc oxide (ζ η 0) mineral is formed to cover the beginning. Oxide (L i C 〇 02) surface. The preparation method comprises dissolving a soluble zinc salt in methanol (ClOH), adding a lithium cobalt oxide (Lic〇〇2) material, mixing and mixing, separating, precipitating, drying and sintering, thereby obtaining a modified bell drill. The oxide (L i C 〇〇 2 ), the modified clock 铦 oxide (L i C 〇 02 ) can be used as a positive electrode material for a secondary battery. [Embodiment]

1264141

The valley and its preferred embodiment are described in detail in conjunction with the detailed description of the present invention. The invention provides a clock secondary battery $ κ battery system to earn money (LlC 〇〇 2): = material, the second oxidation word (ZnO) is plated on the lithium cobalt oxide: uc: 4 temple sign In the formation of the present invention, the preparation of the above modified material is also proposed; the surface of the method. A = CH3 〇 H), then add the clock diamond oxide = the deep temple after drying and smoldering, you can get the modified bell lead oxygen (10) will be, this modified lithium cobalt oxide (LiC 〇〇 2) It is a positive electrode material for the 2 battery of the present invention. If the table is one-person, wherein the weight of the zinc oxide (Zn0) in the soluble salt is ^匕=. 0 "0. 5 to 4. 〇% ;; ☆ from the method can be one of the decantation method, the filtration method, and the plating solution methanol (CH3 〇 H) can be recycled to the drying system at temperature 1 1 〇. (: Perform 24 hours; while the lanthanide temperature is 240 °C to 540 °c for 5 hours 7", please refer to "1A~1D", which is the unmodified saponin (LiCo02) surface. Morphology, surface morphology of lithium cobalt oxide modified with 1 wt·%, 2 wt·% and 4% reciprocal ion concentration. The above figure was dried at 110 ° C for 24 hours and calcined at temperature 440. After 5 hours at °C, the SEM image was observed by an obstructive electron microscope. It can be seen from the figure = the lithium cobalt oxide (LiCo〇2) particles in the "1st image" are smooth, and Lithium cobalt modified and prepared by the present invention in "Fig. 1 B, 1 C, 1 D"

1264141 V. DESCRIPTION OF THE INVENTION (5) The surface of the oxide (Li Co 〇 2) particles has a rough surface formed by zinc oxide (Zn 〇). 'The concentration of zinc ions attached to the surface of the initial oxide (L ic 〇〇 2 ) obtained by inductively coupled plasma atomic emission spectrometer (Icp_AES ) is as follows. The concentration of zinc ions in the solution of Table I is as follows (Wt. % Zn2+ ) —— 2· 4· π I ICP-AES measures the concentration of zinc ions attached to the surface of lithium cobalt oxide II 丨~\------. — — — —| I 0.108 | I 0.206 | I 0.483 |

"" 一— ----——:! 一- 丨,丨_ 1.1 — » "* * ---J The modified material of the positive electrode for lithium secondary battery of the present invention and the preparation method thereof It is an effective and applicable process for commercial mass production, and zinc oxide (Zn0) is plated on the surface of Lithium Oxide (LiCo 2 ) as a modified material of the positive electrode of the secondary battery. The above preparation method and material of the present invention are not modified, 1 Wt·%, 2 wt. °/, respectively. And the lithium cobalt oxide modified by 4 wt·% zinc ion concentration is used as the positive electrode of the secondary battery, and the mixture of the modified lithium cobalt oxide, carbon black and the binder is the positive electrode, and the metal is In the negative electrode, a 1 M solution of L丨p & dissolved in Ethylene-carbonate (EC) and Diethyl-carbonate (DEC) was used as an electrolyte to assemble a lithium secondary battery. This is available, please refer to "Figure 2" for different zinc ions.

1264141

The relationship between the discharge capacitance and the cycle number of the lithium cobalt oxide after the modified lithium metal oxide at a cutoff voltage of 3·〇ν to 4.5V. It can be clearly seen from the figure that when the positive electrode is not modified, as the number of charge and discharge cycles of the battery increases, the discharge capacitance of the battery becomes small, and i wt %, 2 %, and 4 wt·% In the positive electrode whose concentration is modified, the discharge capacitance of the battery is less than that when the positive electrode is not modified at the same cycle number, especially the positive electrode with the modified ion concentration is the best. · ° Please refer to the "Fig. 3" for the relationship between the discharge capacitance of the present invention and the concentration of zinc ions (〇, 1, 2, 4 WU) in the plating solution. The discharge capacity loss of the unmodified (〇wt·%) and the positive electrode modified by the i wt.%, 2 离子 ion concentration can be more clearly seen. The number of cycles of the measurement is 30 cycles, and the discharge capacitance of the positive electrode which has been modified by 2 wt.% is the smallest. In the morning, please refer to the "Fig. 4". The lithium cobalt oxide modified at the ion concentration of 2 wt·% of the present invention has a calcination temperature of 34 Torr. . 44〇, 540 °C discharge capacitance and cycle number relationship diagram. The relevant experiment was carried out for 2 孑 degrees, and the simmering temperature was 34 〇, 44 〇 and 54 〇艽 for 5 hours, and it can be found that in the same cycle number, the electricity is also changed to 40 C. The positive electrode of the quality has the best effect and has better cycleability. Of course, the above examples are only used to illustrate the conditions of the preferred embodiment of the present invention for the preparation of the positive electrode of the pool by the oxidation (Zn0) modification method, i3. the concentration of zinc oxide, and the temperature and time of the calcination... The ion is determined by the content of the soluble zinc salt. 1264141

Page 1 1264141 Brief Description of the Drawing Figure 1A shows the surface morphology of the unmodified lithium cobalt oxide. Figure 1B shows the surface morphology of the lithium cobalt oxide modified by a concentration of 1 wt.% zinc ion. Figure 1C shows the surface morphology of the lithium cobalt oxide modified by a 2 wt.% zinc ion concentration. Figure 1D shows the surface morphology of the lithium cobalt oxide modified by a 4 wt.% zinc ion concentration. Fig. 2 is a graph showing the relationship between the discharge capacitance and the number of cycles of the lithium cobalt oxide after the modification of different zinc ion concentrations of the present invention at a cutoff voltage of 3.0 V to 4.5 V. Fig. 3 is a graph showing the relationship between the discharge capacity loss of the present invention and the zinc ion concentration (0 ❸ , 1, 2, 4 w t · %) in the plating solution. Figure 4 is a diagram showing the discharge capacitance and cycle of the lithium cobalt oxide after the modification of the ion concentration of 2 wt · % at the calcination temperature of 3 40 ° C, 4 40 ° C, and 5 40 ° C. Number relationship diagram.

Page 12

Claims (1)

1264141 VI. Patent Application No. 1 · A positive electrode of a secondary battery is LiC〇〇2, which is a special feature of the secondary battery. The positive electrode of the secondary battery is the lithium cobalt oxide (UCo〇2). The surface of the stomach is: 2, as applied to I plating zinc oxide (Zn0). - ancestor, basin by 兮 #儿, 々 attack of lithium secondary battery positive modification between 0.5 to 4.0%. Reset to lithium cobalt oxide (LiC〇〇2) 3 · Kind of chain primary battery positive terminal ·1:4 „ι I 4丨A ^ τ ^ ^ . Preparation method of modified material, the secondary electricity ^ ^ηΠ Τ Π ^ , rolled UlC〇02), and zinc oxide (ZnO) plated on the surface of the lithium cobalt oxide (LlCo〇2); lithium: iiL.: soluble salt in methanol ( In CH3〇H), the material of the precursor oxide (L 1 C〇02) is further stirred and mixed; the mixture is separated and precipitated by the separation method; n. The precipitate is dried and calcined to obtain modified lithium. The cobalt oxide is ruthenium ruthenium dioxide, and the modified lithium cobalt oxide (L 1 Co02) can be used as the electrode material of the secondary battery. The material + ci ^ the lithium secondary battery described in the third paragraph of the patent scope The positive electrode is modified by A. The preparation method, wherein the weight of zinc oxide (Zn0) in the soluble zinc salt is between 5 and 4.0% of lithium cobalt oxide (LiCo〇2). The method for preparing a positive electrode of a lithium secondary battery according to item 3 is small, and the method for preparing the method may be one of τ of a decantation method or a filtration method. The method for preparing a positive electrode of a lithium secondary battery according to the above, wherein the drying is performed at a temperature of 1 10 ° C for 24 hours. The modification of the positive electrode of the lithium secondary battery according to claim 3 of the patent scope is claimed. 1264141 VI. Patent Application Scope The material preparation method is that the calcination system is carried out at a temperature of 340 ° C to 540 ° C for 5 hours. 0 « « Bill Page 14