Compact structured silicon/carbon composites as high-performance anodes for lithium ion batteries

Abstract

Compact-structured silicon/carbon composites consisting of silicon, graphite, and coal tar pitch pyrolysis carbon are prepared via two heating procedures after liquid solidification. The first heating procedure plays a key role in the formation of compact-structured silicon/carbon composites, in which the coal tar pitch has a good fluidity at 180 °C above the softening temperature, and it is easy to form a uniform coating on the surface of materials. At the same time, the fluidic coal tar pitch could also fill the voids between particles to form compact-structured silicon/carbon composites. As-prepared silicon/carbon composites exhibit moderate reversible capacity of 602.4 mAh g−1, high initial charge-discharge efficiency of 82.3%, and good cycling stability with the capacity retention of 93.4% at 0.1 A g−1 after 50 cycles. It is noteworthy that the synthetic method is scalable which is suitable for mass production.