Preparation And Performance Of Silicon Oxide Composite Anode Materials With High Capacity For Lithium Ion Batteries

Silicon oxide anode materials has a lower cost,higher cycle stability and higher theoretical specific capacity,has therefore may become alternative materials for the anode electrodes of traditional lithium ion power batteries.However,the initial coulombic efficiency of silicon oxide materials is low,and poor conductivity limits its capacity.In this paper,using glucose as the carbon source,a core-shell Si O@C@CMSs composite anode material was prepared by the hydrothermal method combined with subsequent heat treatment to coat a layer of pyrolytic carbon onto the surface of micron-sized Si O particles.Among the samples with different amounts of carbon coating,Si O@C@CMSs-2 had the best performance,delivering a high initial capacity of 1024.5m Ah g^-1 at 50 m A g^-1 and a specific capacity of 638.6 m Ah g^-1 after 60 cycles at a current density of 200 m A g^-1.Even at a current density of 1.5 A g^-1,it was still able to deliver a reversible capacity of about 450 m Ah g^-1.Secondly,using PEG4000,citric acid,glucose and pitch as carbon sources,combined with high temperature heat treatment,the Si O@C@CMSs-2 composite was coated twice,and composite with artificial graphite to obtain Si O@CMSs@C composite anode material.Among the samples secondary coated with different carbon sources,Si O@CMSs@Pitch had the best performance,delivering a high initial capacity of 672.1 m Ah g^-1 at 50 m A g^-1and a specific capacity of 591.7 m Ah g^-1 after 80 cycles at a current density of 200 m A g^-1.Even at a current density of 1.5 A g^-1,it was still able to deliver a reversible capacity of about 430 m Ah g^-1.Finally,the effects of different binders and amount of electrolyte additives on the performance of composites were studied.The anode electrode prepared with PAA as binder is better than PVDF sample in initial coulombic efficiency,cycle performance and rate performance.Among the samples with different amounts of electrolyte additives,FEC-2had the best cycle performance,delivering a specific delithiation capacity of as high as654.7 m Ah g^-1 after 80 cycles at a current density of 200 m A g^-1,and a capacity retention rate of 87.49% compared with the initial cycle at a current density of 200 m A g^-1.