Effects of Na content on structure and electrochemical performances of NaxMnO2＋δ cathode material

• Published in: Transactions of Nonferrous Metals Society of China Vol. 20; no. 10; pp. 1892 - 1898
• Main Author: 杨顺毅 王先友 王莹 李姣姣 杨秀康
• Format: Journal Article
• Language: English
• Published: Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education,School of Chemistry,Xiangtan University,Xiangtan 411105,China%School of Chemical Engineering and Pharmacy,Wuhan Institute of Technology,Wuhan 430073,China 01.10.2010
• Subjects: 循环伏安; 放电容量; 溶胶凝胶工艺; 电化学性能; 电流密度; 阴极材料; sodium manganese oxides; sol-gel technology; cathode material; lithium-ion battery; electrochemical properties
• ISSN: 1003-6326
• DOI: 10.1016/S1003-6326(09)60391-5

Sodium manganese oxides,NaxMnO2＋δ（x = 0.4,0.5,0.6,0.7,1.0;δ = 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＋δ and Na0.7MnO2＋δ 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＋δ gives the second discharge capacity of 188 mA·h/g and remains 77.9% of second discharge capacity after 40 cycles.Na0.7MnO2＋δ 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＋δ still approaches to 107 mA·h/g after 40 cycles.