关键词: 锂离子电池, 硅/硬碳, 壳聚糖, 负极, 复合材料

Abstract:

Silicon/hard carbon composites have been fabricated with the four carbon precursors of sucrose, soluble starch, chitosan, and wheat starch in combination with recycled industrial silicon waste through a water-phase coating plus low temperature carbonization two-step approach. The content of the carbon within the silicon/hard carbon composites of the four precursors and the further influence on cycling performance of the anode have been studied. The results show that chitosan is an outstanding representative for fabrication of silicon/hard carbon composites with a higher carbon content, especially as (c2@Si), after secondary recombination, is more favorable for the cycling stability of the anode. Furthermore, by adding graphite during the fabrication process, the as-prepared silicon/hard carbon/graphite anode (SCG0.2) is able to achieve the specific capacity of 617 mA·h/g after 100 cycles, with the coulombic efficiency being 99.24%. Even after 300 cycles, 637 mA·h/g of specific capacity can be maintained under the high retention of 103.2%; this indicates that the volume expansion issue of Si has been optimized with better cycling stability and the utilization value of silicon waste in energy storage has been realized.

Key words: lithium-ion batteries, silicon/hard carbon, chitosan, anode, composites