Advances in manganese-oxide ‘composite’ electrodes for lithium-ion batteries

Abstract

Recent advances to develop manganese-rich electrodes derived from ‘composite’ structures in which a Li₂MnO₃ (layered) component is structurally integrated with either a layered LiMO₂ component or a spinel LiM₂O₄ component, in which M is predominantly Mn and Ni, are reviewed. The electrodes, which can be represented in two-component notation as xLi₂MnO₃·(1 − x)LiMO₂ and xLi₂MnO₃·(1 − x)LiM₂O₄, are activated by lithia (Li₂O) and/or lithium removal from the Li₂MnO₃, LiMO₂ and LiM₂O₄ components. The electrodes provide an initial capacity >250 mAh g⁻¹ when discharged between 5 and 2.0 V vs. Li⁰ and a rechargeable capacity up to 250 mAh g⁻¹ over the same potential window. Electrochemical charge and discharge reactions are followed on compositional phase diagrams. The data bode well for the development and exploitation of high capacity electrodes for the next generation of lithium-ion batteries.