均匀负载氧化镍纳米颗粒多孔硬碳球的制备及其高性能锂离子电池负极材料应用

摘要

Uniform nickel oxide nanoparticles (~10 nm) embedded in porous hard carbon (HC) spheres (90-130 nm) for high performance lithium ion battery anode materials were synthesized via a hydrothermal method fol owed by impregnation and calcination. The HC spheres, which had abundant micropores and plentiful surface functional groups, al owed firm embedding and uniform dispersion of the NiO nanoparticles. The as-prepared HC/NiO composite anode exhibited excel ent electrochemical performance, including high reversible capacity (764 mAh∙g-1), good cycling stability (a high specific capacity of 777 mAh∙g-1 after the 100th cycle at a current density of 100 mA∙g-1, a capacity retention rate of 101%), and high rate capability (380 mAh∙g-1 even at 800 mA∙g-1). These excel ent electrochemical properties were attributed to the unique structure of NiO nanoparticles tightly embedded in a hard carbon matrix. Anode materials with such a structure have the advantages of improved electronic conductivity, more accessible active sites for lithium ion insertion, and short diffusion paths for lithium ions and electrons. The observed“synergistic effects”between the hard carbon and NiO represent an advance in the electrochemical performance of such composites. The present method is an attractive route for preparing other hard carbon/metal oxide composite anodes for lithium ion batteries.%利用水热法制备了粒径为90-130 nm的多孔硬碳球,并通过浸渍与煅烧的方法制备了硬碳球均匀负载纳米氧化镍颗粒(~10 nm)复合材料。硬碳球的表面官能团和内部的微孔保证了氧化镍颗粒在硬碳上的均匀分布。在100 mA∙g-1的电流密度下,复合材料电极首次充电比容量高达764 mAh∙g-1；在100 mA∙g-1的电流密度下循环100个周期后电极充电比容量保持在777 mAh∙g-1,容量保持率为101%；800 mA∙g-1电流密度下电极的充电比容量达380 mAh∙g-1,显示复合材料电极具有优异的循环性能和倍率性能。硬碳的表面官能团和内部微孔为氧化镍提供了优先形核位点,保证了二者的牢固结合,使复合材料获得了“协同效应”,从而使复合电极具备更短的锂离子扩散路径、更高的电导率和更多的锂离子脱嵌位点。这种方法还可用于制备硬碳/其他金属氧化物复合材料。