【摘要】 本文以光伏产业回收的硅废料为原材料,以蔗糖、可溶性淀粉、壳聚糖、小麦淀粉等含碳化合物作为碳复合的前体,通过常温水相包裹、低温碳化两步工艺制备了硅/硬碳复合材料,对比研究了前体碳的种类对复合物中碳含量的影响以及碳含量对复合负极循环性能的影响。结果表明,以壳聚糖为前体,产物(c@Si)中的碳复合含量高;与一次复合相比,壳聚糖二次复合的负极(c2@Si)循环比容量更高。在壳聚糖、硅复合体系中进一步添加石墨,硅/硬碳/石墨负极(SCG0.2)的比容量可提高至617 mA·h/g(100圈),库仑效率高达99.24%,循环300圈后比容量为637 m A·h/g,负极中硅的体积膨胀问题得到明显改善,循环稳定性明显提高,实现了硅废料在能源存储方面的利用价值。更多还原

【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.更多还原