Abstract
With the pursuit of high energy-density battery systems, cathode materials with high specific capacity and high working voltage are of high interest. Among the transition metal oxide cathode materials, lithium (Li)-rich cation disordered rock salt (DRX) cathode materials are promising candidates for next-generation high-energy-density Li batteries because they offer high specific capacities and cost benefits. Particularly, the manganese (Mn)-based DRXs show more promise due to the utilization of earth abundant material and good thermal stability of Mn. However, these cathodes often face big challenges when cycled in the state-of-the-art LiPF6/carbonate-based electrolytes at voltages up to 4.8 V. These include severe side reactions between the cathode and the electrolyte, transition metal dissolution and structural instability of the cathode particles, all of which result in fast capacity fading. In this work, we developed advanced localized high-concentration electrolytes (LHCEs) to mitigate these problems and enable stable cycling of a DRX cathode material, Li1.2Mn0.6Ti0.2O2 (LMTO). The LHCEs demonstrate high voltage stability of 4.9 V vs. Li/Li+ and capability of forming an ultrathin and stable cathode-electrolyte interphase. Consequently, Li||LMTO half cells with the optimal LHCE exhibit increased capacity, enhanced cycling stability and superior rate capability when compared to the cells with the conventional electrolyte. This work sheds the light of electrolyte development to enable practical DRX cathode-based high-energy Li batteries.
Published Version
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