中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 20 No. 10 October 2010 |
CHEN Quan-qi(陳權啟)1, LI Jiao-jiao(李姣姣)1, YANG Xiu-kang(楊秀康)
（1. Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education,
School of Chemistry, Xiangtan University, Xiangtan 411105, China;
2. School of Chemical Engineering and Pharmacy, Wuhan Institute of Technology, Wuhan 430073, China）
Abstract:Sodium manganese oxides, NaxMnO2+d (x = 0.4, 0.5, 0.6, 0.7, 1.0; d = 0−0.3), were synthesized by solid-state reaction routine combined with sol-gel process. The structure, morphology and electrochemical performances of as-prepared samples were characterized by XRD, SEM, CV, EIS and galvanostatic charge/discharge experiments. It is found that Na0.6MnO2+d and Na0.7MnO2+d have high discharge capacity and good cycle performance. At a current density of 25 mA/g at the cutoff voltage of 2.0−4.3 V, Na0.6MnO2+d gives the second discharge capacity of 188 mA∙h/g and remains 77.9% of second discharge capacity after 40 cycles. Na0.7MnO2+d exhibits the second discharge capacity of 176 mA∙h/g and shows better cyclic stability; the capacity retention after 40 cycles is close to 85.5%. Even when the current density increases to 250 mA/g, the discharge capacity of Na0.7MnO2+d still approaches to 107 mA∙h/g after 40 cycles.
Key words: lithium-ion battery; cathode material; sodium manganese oxides; electrochemical properties; sol-gel technology
