Mechanism of Electrochemical Activity in Li2MnO3

• DOI: 10.1021/cm030047u
• Publication Date: 2003-05-13T06:06:50Z
• Authors: Alastair D. Rober...; Peter G. Bruce
• Keywords: Oxidation state

Lithium intercalation compounds based on lithium manganese oxides are of great importance as positive electrodes for rechargeable batteries. It is widely accepted that Li+ may be extracted (deintercalated) from such accompanied by oxidation Mn up to a maximum state +4. However, it has been suggested recently further removal possible. Among the mechanisms have proposed charge balance beyond +4 or loss O2-. To investigate this phenomenon we selected Li2MnO3, layered compound Li[Li1/3Mn2/3]O2 with ready supply mobile ions but all already in state. We show substantial quantity Li (at least 1.39 Li) removed. At 55 °C occurs exclusively nonaqueous electrolyte, thus generating H+ which exchange one-for-one form Li2-xHxMnO3. The presence between oxide layers results change layer stacking O3 P3, latter being more stable O−H−O bonding. 30 initial oxygen (effective Li2O) involves same proton mechanism observed at °C. reaction partially reversible. On extended cycling material converts spinel.