氮掺杂碳包覆的蛋黄壳结构硅负极材料

Yolk-shell silicon anode material coated with nitrogen-doped carbon

采用间苯二酚-甲醛为碳源,三聚氰胺为氮源,以NaOH为蚀刻剂,成功合成氮掺杂碳包覆的蛋黄壳结构硅(Si@void@N-C)锂离子电池复合负极材料.对样品进行XRD、SEM和X射线电子能谱,透射电子显微镜(TEM)和电化学测试等表征及测试.结果表明,成功合成了蛋黄壳结构的Si@void@N-C复合负极材料.同时,该复合材料具有优异的电化学性能,以0.1 A/g的电流密度进行充放电,首次容量可达1282.3 mAh/g,经过100次循环后,其比容量仍高达994.2 mAh/g,其容量保持率为77.5%,表现出了良好的循环性能.Si@void@N-C材料中,氮掺杂的碳壳可以增加复合材料的导电性,同时,蛋黄壳结构可有效缓解硅的体积效应,有利于形成稳定的SEI膜,从而提高电池的循环稳定性.

Using resorcinol-formaldehyde resin as the carbon source,melamine as the nitrogen source,and NaOH as the etchant,a nitrogen-doped carbon-coated silicon(Si@void@N-C)anode material with a yolk-shell structure was synthesized.The samples were characterized and tested by XRD,SEM and X-ray photoelectron spectroscopy,TEM,and electrochemical tests;the results confirmed that a Si@void@NC composite anode material with a yolk-shell structure was successfully synthesized.The material was found to have excellent electrochemical performance.The initial capacity reached 1282.3 mA/g after charging and discharging at a current density of 0.1 A/g.After 100 cycles,its specific capacity was as high as 994.2 mAh/g with a capacity retention of 77.5%,demonstrating good cycle performance.The nitrogen-doped carbon shell of the Si@void@N-C material helps with the electrical conductivity of the composite material.Meanwhile,the yolk-shell structure effectively alleviates the volume effect of silicon;this feature is beneficial to the formation of a stable SEI film and improves the cycle stability of the battery.