Li/Mn-Rich Cathode Materials With Low-Cobalt Content And Core-Shell Particle Design For High-Energy Lithium Ion Batteries

Li/Mn-rich positive electrode materials are widely known for their high energy content, which exceeds that of current cathodes significantly. Their implementation in practical high-energy lithium ion batteries has to date been hindered by various technical challenges, most of all, their insufficient long-term charge/discharge cycling performance. Here, a new concept for designing core-shell (CS) materials for this class is introduced, which is based on cathode particles, which are specifically designed to have an anionic redox-rich core and a shell with reduced anionic redox. This material design approach aims to overcome the drawback of having the sensitive anionic redox at the electrolyte/active material interface, and, therefore, extenuating the phase degradation from layered- to spinel- or even rock salt-structure. In this work, the effect of a CS particle design with a Co-free, Mn-rich core and a Co-containing shell with lower Mn content is studied. The spherical cathode particles, produced by a Couette Taylor Flow Reactor, enable a superior electrochemical performance with excellent initial Coulombic efficiencies of 90%-95% and improved long-term cycling performances compared to the reference materials, consisting of the pure core or pure shell composition. (C) 2020 The Electrochemical Society ("ECS"). Published on behalf of ECS by IOP Publishing Limited.