Synthesis of high-capacity Ti- and/or Fe-substituted Li₂MnO₃ positive electrode materials with high initial cycle efficiency by application of the carbothermal reduction method

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• 作者：Mitsuharu Tabuchi ; Yoko Nabeshima ; Tomonari Takeuchi ; Hiroyuki Kageyama ; Junichi Imaizumi ; Hideka Shibuya ; Junji Akimoto
• 关键词：Synthesis ; Lithium batteries ; Positive electrode material ; Lithium iron oxide ; Lithium manganese oxide ; Carbothermal reduction
• 刊名：Journal of Power Sources
• 出版年：2013
• 出版时间：1 January, 2013
• 年：2013
• 卷：221
• 期：Complete
• 页码：427-434
• 全文大小：1211 K

文摘

Carbothermal reduction using sucrose was applied to Fe- and/or Ti-substituted Li₂MnO₃ positive electrode materials to improve their poor initial cycle efficiency (<60 % ) of 2.0-4.8?V. The initial cycle efficiency was improved from 53 % to 68 % for Li_1+x(Ti_0.5Mn_0.5)_1?xO₂, 63 % -72 % for Li_1+x(Fe_0.3Mn_0.7)_1?xO₂, or 62 % -78 % for Li_1+x(Fe_0.2Ti_0.2Mn_0.6)_1?xO₂ by application of the carbothermal reduction process. All samples belong to 3.2?V class positive electrode material with high initial discharge capacity higher than 220?mAh?g^?1. The shape change of discharge curve with cycle progression was suppressed for all reduced samples. The compositional, transition metal valence state, and structural and powder property changes occurring before and after carbothermal reduction processing were examined to construct the material design concept of attractive Li₂MnO₃-based positive electrode candidates using only naturally abundant and cheap elements (Ti and Fe) as constituent metals.