尾-NaMnO2: A High-Performance Cathode for Sodium-Ion Batteries

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• 作者：Juliette Billaud ; Rapha毛le J. Cl茅ment ; A. Robert Armstrong ; Jes煤s Canales-V谩zquez ; Patrick Rozier ; Clare P. Grey ; Peter G. Bruce
• 刊名：Journal of the American Chemical Society
• 出版年：2014
• 出版时间：December 10, 2014
• 年：2014
• 卷：136
• 期：49
• 页码：17243-17248
• 全文大小：428K
• ISSN：1520-5126

文摘

There is much interest in Na-ion batteries for grid storage because of the lower projected cost compared with Li-ion. Identifying Earth-abundant, low-cost, and safe materials that can function as intercalation cathodes in Na-ion batteries is an important challenge facing the field. Here we investigate such a material, 尾-NaMnO₂, with a different structure from that of NaMnO₂ polymorphs and other compounds studied extensively in the past. It exhibits a high capacity (of ca. 190 mA h g^鈥? at a rate of C/20), along with a good rate capability (142 mA h g^鈥? at a rate of 2C) and a good capacity retention (100 mA h g^鈥?after 100 Na extraction/insertion cycles at a rate of 2C). Powder XRD, HRTEM, and ²³Na NMR studies revealed that this compound exhibits a complex structure consisting of intergrown regions of 伪-NaMnO₂ and 尾-NaMnO₂ domains. The collapse of the long-range structure at low Na content is expected to compromise the reversibility of the Na extraction and insertion processes occurring upon charge and discharge of the cathode material, respectively. Yet stable, reproducible, and reversible Na intercalation is observed.