Nano silicon encapsulated in modified copper as an anode for high performance lithium ion battery

Abstract

Silicon, owing to its exceptionally high theoretical capacity of 4200 mAh/g, is one of the potential anode materials explored by the lithium ion battery community. However, it undergoes tremendous volume expansion upon cycling that result in the material fracture and cracking, leading to electronic isolation and loss of cycleable Li. In the present study, Si-nanopowder inserted Cu plates are utilized as current collectors so as to accommodate the volume expansion and electronic isolation caused by the secession of active materials from the electrode upon electrochemical cycling. The Cu plates are etched with sandpapers of different grades to effectively enable the Si insertion by a simple and facile brushing method. Electrodes were finally coated with a binder layer for encapsulation of Si active materials and were compared in terms of the electrochemical performances. The electrochemical investigations reveal that the electrodes fabricated by the surface modified Si/Cu plates with the SiC sandpaper #800 coupled with the binder coating afforded the best electrochemical performance among the electrodes investigated with excellent capacity retention of 1074 mAh/g even after 1000 cycles.