| Silicon is the most promising new generation of high-specific capacity negative electrode materials that replaces graphite,and its theoretical gram is about 4200m Ah·g-1,but its cycle stability is poor,and the problem of low efficiency of Kurun has been plagued with high-volume lithium-ion batteries.In order to solve the current problems of silicon negative materials,this paper explores its electrochemical performance improvement from two aspects.On the one hand,it is to apply pre-lithiative means,select a suitable silicon alloy negative electrode material,prepare Li-Si,Li-Cu alloy to pre-lithium the silicon alloy negative electrode material,determine alloy ingredients,add mode,and add amount by experiment Exploring its pre-lithiuming effects;secondly,it is to explore the coating of polytetrafluoroethylene（PVDF）as an organic carbon source on different additions.The micro-morphology and structure of silicon carbon composite materials such as scanning electron microscopy（SEM）,Raman spectroscopy（Raman）,and equipment such as blue electricity test system and package The negative electrode material is electrochemically based on electrochemical properties.The test results are as follows:1.When the amount of nano-silicon alloy negative powder is added to4.5%,the Cullen efficiency is 90.90%,and the discharge ratio is 470.35m Ah·g-1.After 100 cycles,the capacity retention rate is 82.81%,electrochemical Performance comparison of pure graphite negative electrode is improved.It was then determined that Li/Si-2（Li 10g,Si 150g）was added as an additive to the pre-lithium-based effect,and the discharge ratio was 504.67m Ah·g-1,the first week Kurlen efficiency was 91.35%,100 The capacity retention rate after the second cycle is 77.01%.In contrast,the first week of the unpredalized negative electrode material has a significant increase,the discharge ratio capacity is also increased.The experimental results also indicate that directly mixed in the aqueous negative slurry,the electrochemical performance is better than the painting mode,can be applied in industrial production;when the amount of addition is increased,the electrochemical performance will increase.The above conclusion proof can utilize Li-Si alloys to perform pre-lithium chemical materials.2,Li-Cu alloy pre-lithiumd lithiation effect is more prominent.When Li/Cu-2（Li 10g,Cu 40g）is used,the alloy powder is discharged directly to the negative electrode sheet,and the resulting battery performance is preferably460.63m Ah·g-1.The first week of Kurun efficiency is 92.15%.The first active breakthrough is 92%.It is not easy.This pre-lithiation method is feasible.3.Polyvinylidene fluoride（PVDF）The degree of electrochemical properties of the active silicon particles at different amounts of high temperature cracking at different additions.When the PVDF is added to 200g,the amorphous carbon is almost completely covered with the surface of the silicon particles,forming a carbon coated nuclear shell structure,and the buckless silicon can be greatly expanded during the charge and discharge process,and thin on the surface The stable SEI film,the capacity attenuation is significantly slow.Therefore,Si/C-3（PVDF is 200g）discharge ratio capacity can reach460.23m Ah·g-1the first week of Coulomb performance is as high as 90.37%,after 150 cycles,still maintain better circulatory performance（capacity retention ratio is about 86.43%）.Description Cover can improve the electrochemical properties of the negative electrode material. |
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