Lithium–manganese oxide electrodes with layered–spinel composite structures xLi₂MnO₃ · (1 − x)Li_1 + yMn_2 − yO₄ (0 <&#

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• 作者：Johnson ; C.S. ; Li ; N. ; Vaughey ; J.T. ; Hackney ; S.A. ; Thackeray ; M.M.
• 关键词：Lithium batteries ; Composite electrode ; Structure ; Spinel ; Li₂MnO₃
• 刊名：Electrochemistry Communications
• 出版年：2005
• 出版时间：May, 2005
• 年：2005
• 卷：7
• 期：5
• 页码：528-536
• 全文大小：405 K

文摘

Lithium–manganese oxide electrodes containing structurally integrated domains of layered and spinel phases, represented in two-component notation as xLi₂MnO₃ · (1 − x)Li_{1 + y}Mn_{2 − y}O₄ (0 < x < 1, 0 y 0.33), were synthesized and evaluated in lithium cells. During an initial charge to 5 V, lithium and/or lithia (Li₂O) are extracted from the spinel and layered components at distinct voltages. When cycled between 5 and 2 V, a rechargeable capacity >250 mAh/g can be achieved from electrodes prepared at 400 °C during the early cycles. The discharge profiles confirm the layered–spinel character of the composite electrodes. The Li₂MnO₃ Mn(IV) content in the parent structure and the degree to which lithium and lithia are extracted from the electrode during the initial charge can be used to control the average manganese oxidation state at the end of discharge and electrochemical cycling stability.