Small polaron migration in Li_x

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• 作者：Chuying Ouyang ; Yanlan Du ; Siqi Shi ; Minsheng Lei
• 关键词：Jahn– ; Teller small polaron ; Migration energy barrier ; Lithium ion battery ; LiMn₂O₄ cathode
• 刊名：Physics Letters A
• 出版年：2009
• 出版时间：20 July 2009
• 年：2009
• 卷：373
• 期：31
• 页码：2796-2799
• 全文大小：331 K

文摘

Migration of small polarons in λ-MnO₂, Li_0.5Mn₂O₄ and LiMn₂O₄ is studied via first principles calculations. Migration energy barriers of single small polaron migrations in λ-MnO₂, Li_0.5Mn₂O₄ and LiMn₂O₄ are 0.22 eV, 0.45 eV and 0.35 eV, respectively. The energy level changes of Mn-3d states along the polaron migration path are analyzed in detail. Results indicate that the activation energy barrier of polaron migration is strongly associated with the energy level shift of Mn-3dz² orbital, which is dependent on the short range structural arrangement of Mn³⁺/Mn⁴⁺ in the crystal. The electrical conduction properties of Li_xMn₂O₄ at room temperature are then discussed.