Research Of Si Anode For Lithium-Ion Batteries Prepared By Mechanical Alloying Method

In this paper,silicon-based lithium-ion battery negative electrode was primaryresearch objectives in new energy materials research,mechanical alloying method forthe preparation of materials,pure Si as the main study object,its MA time is20h to100h,and in the latter part of the process of material preparation add graphite,SP andAl doped.Use X-ray diffraction for structural analysis,use SEM for surfacetopography analysis,use particle size analyzer for particle size analysis,LAND batterytest system used to charge and discharge test,use IM6electrochemical workstation fordynamic analysis,based on the above analysis of materials for lithium-ion batterynegative electrode,propose reasonable measures for improvement.For pure Si materials,with increasing MA time,the degree of amorphousincreased,but can not formed completely amorphous phase,in which the highestdegree of amorphous is100h material;after MA,materials particle size from29μminto0.2μm;analysis the surface morphology of different MA time has found that rawmaterial was large block and after MA was small round and in100h MA time materialhas agglomerated particles.By research the charge and discharge result of differentMA time materials found that Si has a high capacity in first discharge,but has largecapacity loss in later cycle and poor cycling performance,after MA,the first dischargecapacity of Si has increased.In dynamic analysis we found that MA Si has loosestructure so its diffusion coefficient increased.In order to improve the cycle performance,we use Si doped.After80h MA,wefound carbon-doped and Al-doped both formed a large number of inert material which can not reaction with Li,however,has a higher amorphous degree;the average particle size was same with pure Si which after MA,and no massive particle,have agglomerated particles.By charge and discharge test found,doped material's first discharge capacity decreased,but improve cycling performance,Al-doped material has a best cycling performance capacity loss was stable.