Controlled synthesis of nanosized Si by magnesiothermic reduction from diatomite as anode material for Li-ion batteries
来源期刊：International Journal of Minerals Metallurgy and Materials2020年第4期
论文作者：Li-fen Guo Shi-yun Zhang Jian Xie Xin-bing Zhao
文章页码：515 - 525
摘 要：Li-ion batteries（LIBs） have demonstrated great promise in electric vehicles and hybrid electric vehicles. However, commercial graphite materials, the current predominant anodes in LIBs, have a low theoretical capacity of only 372 m Ah·g-1, which cannot meet the everincreasing demand of LIBs for high energy density. Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites. Synthesis of nanoscale Si in a facile, cost-effective way, however, still poses a great challenge. In this work, nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source. It was found that the nanoscale Si prepared under optimized conditions（800°C, 10 h） can deliver a high initial specific capacity(3053 m Ah·g-1 on discharge, 2519 m Ah·g-1 on charge) with a high first coulombic efficiency（82.5%）. When using sand-milled diatomite as a precursor, the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency（85.6%）. The Si–C（Si : graphite = 1:7 in weight） composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 m Ah·g-1 at 100 m A·g-1), good rate capability(587 m Ah·g-1 at 500 m A·g-1), and a long cycle life(480 m Ah·g-1 after 200 cycles at 500 m A·g-1). This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.
Li-fen Guo1，Shi-yun Zhang1，Jian Xie1,2，Xin-bing Zhao1,2
1. State Key Laboratory of Silicon Materials, School of Materials Science and Engineering, Zhejiang University2. Key Laboratory of Advanced Materials and Applications for Batteries of Zhejiang Province
摘 要：Li-ion batteries（LIBs） have demonstrated great promise in electric vehicles and hybrid electric vehicles. However, commercial graphite materials, the current predominant anodes in LIBs, have a low theoretical capacity of only 372 m Ah·g-1, which cannot meet the everincreasing demand of LIBs for high energy density. Nanoscale Si is considered an ideal form of Si for the fabrication of LIB anodes as Si–C composites. Synthesis of nanoscale Si in a facile, cost-effective way, however, still poses a great challenge. In this work, nanoscale Si was prepared by a controlled magnesiothermic reaction using diatomite as the Si source. It was found that the nanoscale Si prepared under optimized conditions（800°C, 10 h） can deliver a high initial specific capacity(3053 m Ah·g-1 on discharge, 2519 m Ah·g-1 on charge) with a high first coulombic efficiency（82.5%）. When using sand-milled diatomite as a precursor, the obtained nanoscale Si exhibited a well-dispersed morphology and had a higher first coulombic efficiency（85.6%）. The Si–C（Si : graphite = 1:7 in weight） composite using Si from the sand-milled diatomite demonstrated a high specific capacity(over 700 m Ah·g-1 at 100 m A·g-1), good rate capability(587 m Ah·g-1 at 500 m A·g-1), and a long cycle life(480 m Ah·g-1 after 200 cycles at 500 m A·g-1). This work gives a facile method to synthesize nanoscale Si with both high capacity and high first coulombic efficiency.
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