材料科学
法拉第效率
阳极
硅
化学工程
氧化物
金属
硅酸盐
放热反应
介孔材料
锂(药物)
蚀刻(微加工)
矿物学
催化作用
图层(电子)
纳米技术
电极
冶金
化学
有机化学
医学
物理化学
内分泌学
工程类
作者
Jaegeon Ryu,Dongki Hong,Myoungsu Shin,Soo‐Jin Park
出处
期刊:ACS Nano
[American Chemical Society]
日期:2016-11-14
卷期号:10 (11): 10589-10597
被引量:92
标识
DOI:10.1021/acsnano.6b06828
摘要
Three-dimensional (3D) hyperporous silicon flakes (HPSFs) are prepared via the chemical reduction of natural clay minerals bearing metal oxides. Natural clays generally have 2D flake-like structures with broad size distributions in the lateral dimension and varied thicknesses depending on the first processing condition from nature. They have repeating layers of silicate and metal oxides in various ratios. When the clay mineral is subjected to a reduction reaction, metal oxide layers can perform a negative catalyst for absorbing large amounts of exothermic heat from the reduction reaction of the silicate layers with metal reductant. Selectively etching out metal oxides shows a hyperporous nanoflake structure containing 100 nm macropores and meso-/micropores on its framework. The resultant HPSFs are demonstrated as anode materials for lithium-ion batteries. Compared to conventional micro-Si anodes, HPSFs exhibit exceptionally high initial Coulombic efficiency over 92%. Furthermore, HPSF anodes show outstanding cycling performance (reversible capacity of 1619 mAh g–1 at a rate of 0.5 C after 200 cycles, 95.2% retention) and rate performance (∼580 mAh g–1 at a rate of 10 C) owing to their distinctive structure.
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