材料科学
非阻塞I/O
氧化物
乙二醇
化学工程
粒度
金属
电化学
柠檬酸
冶金
化学
物理化学
有机化学
电极
工程类
催化作用
作者
Seung Ho Choi,Sun-Kyu Park,Jung-Kul Lee,Yun Chan Kang
标识
DOI:10.1016/j.jpowsour.2015.03.026
摘要
Multi-shell structured binary transition metal oxide powders with a Ni/Co mole ratio of 1:2 are prepared by a simple spray drying process. Precursor powder particles prepared by spray drying from a spray solution of citric acid and ethylene glycol have completely spherical shape, fine size, and a narrow size distribution. The precursor powders turn into multi-shell powders after a post heat-treatment at temperatures between 250 and 800 °C. The multi-shell structured powders are formed by repeated combustion and contraction processes. The multi-shell powders have mixed crystal structures of Ni1−xCo2O4−x and NiO phases regardless of the post-treatment temperature. The reversible capacities of the powders post-treated at 250, 400, 600, and 800 °C after 100 cycles are 584, 913, 808, and 481 mA h g−1, respectively. The low charge transfer resistance and high lithium ion diffusion rate of the multi-shell powders post-treated at 400 °C with optimum grain size result in superior electrochemical properties even at high current densities.
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