天然石墨表面自组装SnO2-FeO(OH)高容量锂离子电池负极

利用双水解反应制备含稳定胶束H₂SnO₃@Fe(OH)₃的胶体溶液，并在静电吸附作用下将其自组装到天然石墨表面，经水热反应构建了表面具有SnO₂-FeO(OH)精细结构的石墨负极体系. 结构表征结果显示:水热反应后天然石墨表面存在致密的纳米结构包覆层，该包覆层是由超细SnO₂纳米晶颗粒(粒径 < 6 nm)弥散的非晶态FeO(OH)组成. 电化学测试结果表明:在石墨表面构建SnO₂-FeO(OH)精细纳米结构不仅能提升其充电/放电容量，而且还可改善其循环稳定性. 在0.1C充放电流密度下，经表面修饰的天然石墨首次充放电效率达到77.5%，循环100次后放电容量仍能维持在384.4 mAh/g，放电容量较商用天然石墨提高了23%.

The Self-assembled SnO2-FeO(OH) on Natural Graphite Surface as A High-capacity Anode for Lithium Ion Batteries

A stable H₂SnO₃@Fe(OH)₃ colloidal solution is prepared through double hydrolysis. It is self-assembled on the surface of natural graphite under the action of electrostatic adsorption. After the hydrothermal reaction, the H₂SnO₃@Fe(OH)₃ colloidal micelles on the surface of graphite are changed into SnO₂-FeO(OH) co-dispersed structures. The structural characterizations show that there is a dense nanostructure coating on the surface of natural graphite after hydrothermal reaction, composed of ultrafine SnO₂ nanocrystalline particles (< 6 nm) and amorphous FeO(OH). The electrochemical testing results indicate that the SnO₂-FeO(OH) fine nanostructures can not only improve the charge/discharge capacity of graphite, but also improve its cyclic stability. At a current density of 0.1C, the initial cycle efficiency of the modified graphite can reach 77.5%. After 100 cycles, the discharge capacity of modified graphite can be maintained at 384.4 mAh/g, which is 23% higher than that of commercial graphite.