Lithium negative pole, preparation method thereof and battery comprising lithium negative pole

A lithium negative electrode and battery technology, which is applied in the field of electrochemical batteries, can solve the problems of cycle performance degradation and large changes in the surface morphology of lithium powder electrodes, improve safety performance and cycle performance, reduce the probability of dendrite formation, and The effect of a large adjustment range

Inactive Publication Date: 2012-02-15
SHANGHAI INST OF SPACE POWER SOURCES
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, when the discharge capacity is large, the surface morphology of the lithi

Method used

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  • Lithium negative pole, preparation method thereof and battery comprising lithium negative pole
  • Lithium negative pole, preparation method thereof and battery comprising lithium negative pole
  • Lithium negative pole, preparation method thereof and battery comprising lithium negative pole

Examples

Experimental program
Comparison scheme
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Example Embodiment

[0026] Example 1

[0027] Use mesophase carbon microspheres (MCMB) as the lithium carrier, mixed with conductive agent carbon black (SP) and binder polyvinylidene fluoride (PVDF) at a mass ratio of 91:3:6, and use N-methyl-2- Pyrrolidone (NMP) is a solvent, mixed with a high-speed emulsifier to form a slurry, and then uniformly coated on the current collector Cu foil, and then dried in a vacuum drying oven at 60°C for 24 hours for use. Using lithium metal sheet as the negative electrode, mesophase carbon microspheres as the counter electrode, Celgrad 2325 as the separator, 1.2 mol / L lithium hexafluorophosphate (LiPF 6 ) / Ethylene Carbonate (EC) + Methyl Ethyl Carbonate (EMC) (volume ratio 3:7) is the electrolyte to assemble the battery.

[0028] The battery is first charged and discharged with a current density of 40 mA / g, and the voltage range is 0-3 V. After 10 cycles, discharge to 0 V, and then discharge at a constant current of 40 mA / g for 9 h. Electrochemically deposit a metal...

Example Embodiment

[0029] Example 2

[0030] Graphite (MCP-1) is used as the lithium carrier, mixed with conductive agent carbon black (SP) and binder polyvinylidene fluoride (PVDF) at a mass ratio of 91:3:6, and N-methyl-2-pyrrolidone ( NMP) is a solvent, mixed with a high-speed emulsifier to form a slurry, and then uniformly coated on the current collector Cu foil, and then dried in a vacuum drying oven at 60°C for 24 hours for use. Using lithium metal sheet as the negative electrode, graphite as the counter electrode, Celgrad 2325 as the separator, 1.2 mol / L lithium hexafluorophosphate (LiPF 6 ) / Ethylene carbonate (EC) + methyl ethyl carbonate (EMC) (volume ratio 3:7) + fluoroethylene carbonate (FEC, 5wt%) as the electrolyte to assemble the battery.

[0031] The battery is first charged and discharged with a current density of 31 mA / g, and the voltage range is 0-2 V. After 10 cycles, discharge to 0V, and then discharge at a constant current of 31 mA / g for 5 hours. Electrochemically deposit a meta...

Example Embodiment

[0032] Example 3

[0033] Use hard carbon (HC) as the lithium carrier, mixed with conductive agent carbon black (SP), conductive agent vapor-grown carbon fiber (VGCF), and binder polyvinylidene fluoride (PVDF) at a mass ratio of 92:2:1:5, Using N-methyl-2-pyrrolidone (NMP) as the solvent, mix it with a high-speed emulsifier to form a slurry, and then uniformly coat it on the current collector Cu foil, and then dry it in a vacuum drying oven at 60°C for 24 hours for use. Using lithium metal sheet as the negative electrode, hard carbon as the counter electrode, Celgrad 2325 as the separator, 1.2 mol / L lithium hexafluorophosphate (LiPF 6 ) / Ethylene Carbonate (EC) + Methyl Ethyl Carbonate (EMC) (volume ratio 3:7) is the electrolyte to assemble the battery.

[0034] The battery is first charged and discharged with a current density of 40 mA / g, and the voltage range is 0-3 V. After 10 cycles, discharge to 0 V, and then discharge at a constant current of 40 mA / g for 4 h. Electrochemicall...

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Abstract

The invention discloses a lithium negative pole, a preparation method thereof and a battery comprising the lithium negative pole. The preparation method of the lithium negative pole comprises the following specific steps: step 1, lithium embedding: coating a carbon material on an affluxion body Cu foil and drying, thereby obtaining a carbon material pole piece; packing a battery by taking a lithium metal piece as a negative pole and the carbon material pole piece as a counter electrode, carrying out charge-discharge circulation so as to finish the step of lithium embedding; and step2,deposition of a metal lithium layer through overdischarge: carrying out overdischarge on the finished embedding lithium step battery at current density of 10-100 m A/g through constant current discharging for 2-20 hours, thus the lithium negative pole is obtained on a carbon material pole piece surface electrochemical deposition lithium metal layer. The lithium negative pole provided by the invention has the advantages of taking a carbon electrode as a carrier; compared with a general lithium metal negative pole, the safety feature and the cycle performance are effectively improved, the negative pole capacity can be designed by self according to the requirements of the positive pole capacity, therefore the adjustable range is large.

Description

technical field [0001] The invention belongs to the field of electrochemical batteries, and relates to a lithium secondary battery, in particular to a lithium negative electrode, a preparation method thereof and a battery containing the lithium negative electrode. Background technique [0002] Metal lithium has a potential of -3.045 V relative to the standard hydrogen electrode, and a specific capacity of 3861 mAh / g, which is close to 10 times the specific capacity of conventional carbon negative electrodes (372 mAh / g for graphite), which has a good development prospect. However, the lithium negative electrode is continuously dissolved and deposited during the charging and discharging process, which is prone to produce dendrites, resulting in a decrease in cycle performance. In severe cases, the dendrites will pierce the separator and contact the positive electrode, resulting in internal short circuit, and even safety accidents such as fire or explosion. [0003] In order to...

Claims

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Application Information

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IPC IPC(8): H01M4/66H01M4/139H01M4/13H01M10/0525
CPCY02E60/10
Inventor 刘雯
Owner SHANGHAI INST OF SPACE POWER SOURCES
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