Soft chemical synthesis and electrochemical properties of Li_0.90Mn_0.90Ti_0.10O₂ with the Na_0.44MnO₂-type tunnel structure

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• 作者：Junji Akimoto ; Hiroshi Hayakawa ; Naoya Ishida ; Fuji Funabiki ; Norihito Kijima ; Hideka Shibuya ; Junichi Imaizumi
• 关键词：Lithium manganese oxide ; Positive electrode materials ; Na0.44MnO2-type tunnel structure ; Ion exchange ; Chemical lithiation
• 刊名：Journal of Power Sources
• 出版年：2013
• 出版时间：15 December, 2013
• 年：2013
• 卷：244
• 期：Complete
• 页码：382-388
• 全文大小：2073 K

文摘

We have successfully prepared Li_0.44+xMn_1?yTi_yO₂ having the Na_0.44MnO₂-type framework structure by ion-exchange technique in molten LiNO₃ and LiNO₃-LiOH salts at 270?¡ãC from the precursor Na_0.44Mn_1?yTi_yO₂ synthesized at 800?¡ãC using homogeneous and fine Mn-Ti hydroxides as starting materials. The needle-shaped particle length can be successfully reduced. The chemical composition and the crystal structure of Li_0.44+xMn_1?yTi_yO₂ were confirmed by using ICP-AES and XRD Rietveld analyses. The electrochemical measurements revealed that both the charge and discharge properties of the obtained Li_0.44+xMn_1?yTi_yO₂ samples were drastically improved. Especially, the obtained Li_0.71Mn_0.90Ti_0.10O₂ exhibited initial charge and discharge capacities of 176 and 212?mAh?g^?1, respectively, with an average discharge voltage of 3.56?V vs. Li/Li⁺. The resultant initial discharge energy density was achieved to be 755?Wh?kg^?1. A further chemical lithiation treatment was performed using LiI for the Li_0.63MnO₂ and Li_0.71Mn_0.90Ti_0.10O₂ samples. The electrochemical measurements between 4.8 and 2.5?V for the lithiated Li_0.83MnO₂ and Li_0.90Mn_0.90Ti_0.10O₂ samples showed the improvement of the initial charge capacities. The rate capability test revealed Li_0.90Mn_0.90Ti_0.10O₂ retains 81 % of its discharge capacity in going from 1C to 5C rate. The excellent high rate capability and good cycling performance of Li_0.90Mn_0.90Ti_0.10O₂ is particularly attractive for electric vehicle applications.