Nitrogen-Doped Hollow Carbon Nanospheres for High-Performance Li-Ion Batteries
Nitrogen-Doped Hollow Carbon Nanospheres for High-Performance Li-Ion Batteries
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用于高性能锂离子电池的氮掺杂中空碳纳米球
DOI：
10.1021/acsami.6b14840
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发表时间：
2017
影响因子：
9.5
通讯作者：
Ji Hengxing
中科院分区：
文献类型：
--
作者：
Yang Yufen;Jin Song;Zhang Zhen;Du Zhenzhen;Liu Huarong;Yang Jia;Xu Hangxun;Ji Hengxing
N掺杂的碳材料对于锂离子电池（LIB）的阳极具有特别的吸引力，因为它们的高表面积、上级导电性和优异的机械强度，其可以通过在电解质和电极之间的界面处吸附/脱附Li+来存储能量。通过乳液界面反应合成的咪唑骨架-8沸石纳米球直接碳化，得到了壳层厚度（20 nm至实心球）可调、N掺杂浓度（3.9 ~ 21.7 at %）不同的N掺杂空心碳纳米球。优化的阳极材料具有20 nm的壳层厚度，并含有16.6原子%的N掺杂剂，主要是吡啶和吡咯。该阳极在100 mA g-1和5 A g-1条件下循环1000次，比容量分别为2053 mA h g-1和879 mA h g-1，具有良好的上级循环稳定性。其电化学性能的提高主要归因于：（1）以Li+吸附为主的储能机制防止了电极材料的体积变化;（2）由纳米级初级粒子组装而成的中空纳米结构防止了纳米粒子的团聚，有利于Li+的扩散;（4）石墨碳纳米结构保证了良好的导电性。
N-doped carbon materials is of particular attraction for anodes of lithium-ion batteries (LIBs) because of their high surface areas, superior electrical conductivity, and excellent mechanical strength, which can store energy by adsorption/desorption of Li+at the interfaces between the electrolyte and electrode. By directly carbonization of zeolitic imidazolate framework-8 nanospheres synthesized by an emulsion-based interfacial reaction, we obtained N-doped hollow carbon nanospheres with tunable shell thickness (20 nm to solid sphere) and different N dopant concentrations (3.9 to 21.7 at %). The optimized anode material possessed a shell thickness of 20 nm and contained 16.6 at % N dopants that were predominately pyridinic and pyrrolic. The anode delivered a specific capacity of 2053 mA h g–1at 100 mA g–1and 879 mA h g–1at 5 A g–1for 1000 cycles, implying a superior cycling stability. The improved electrochemical performance can be ascribed to (1) the Li+adsorption dominated energy storage mechanism prevents the volume change of the electrode materials, (2) the hollow nanostructure assembled by the nanometer-sized primary particles prevents the agglomeration of the nanoparticles and favors for Li+diffusion, (3) the optimized N dopant concentration and configuration facilitate the adsorption of Li+; and (4) the graphitic carbon nanostructure ensures a good electrical conductivity.