化学工程
分析化学(期刊)
钠离子电池
电解质
锂(药物)
电池(电)
锂离子电池
电极
化学
作者
Masaki Matsui,Fumikazu Mizukoshi,Hirona Hasegawa,Nobuyuki Imanishi
标识
DOI:10.1016/j.jpowsour.2020.229346
摘要
Abstract The electrochemical property of the layered sodium transition metal oxide is dependent upon the reversible phase transition during the sodium intercalation/deintercalation process. Here we synthesized Ca-doped P3-type NaxNi1/3Mn1/3Co1/3O2 as a potential cathode active material for sodium-ion batteries. The Ca-doping leads the lattice expansion along the c-axis, due to the electrostatic repulsion between Ca2+ ions and the transition metal ions. Even though the doped Ca2+ ions occupy Na+ sites, the Ca-doped cathode shows lower overpotential during the galvanostatic charge-discharge process. The electrochemical impedance spectroscopy proved that the charge-transfer resistance of the Ca-doped layered oxide is lower than the Ca-free one at low cell voltage. These results indicate that the Ca-doping enhances the mobility of the Na+ ions in the layered structure. The doped Ca2+ ions also suppress the irreversible O′3–O1 phase transition upon the full deintercalation of the sodium ions from the layered structure. The improved stability of the Ca-doped NaxNi1/3Mn1/3Co1/3O2 leads better capacity retention during the galvanostatic cycling.
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