Upgrading the electrochemical performance of Li-rich Mn-based cathodes through additional fast Li storage assisted by few-layer MXene

Li-rich Mn-based [xLi2MnO3 center dot(1-x)LiMO2] (LR) cathodes are low cost and have high energy density, indicating high commercialization potential. However, the low initial coulombic efficiency, poor rate performance, and inferior cycling durability of LR cathodes confer difficulty in such commercialization. Herein, we proposed the use of a few-layer MXene (Ti3C2) to improve electrochemical performance. We found that the few-layer MXene can improve the conductivity and provide additional capacity at low voltage (2.25 V), thereby greatly increasing the initial coulombic efficiency, rate, and cycle performance. The additional capacity may have originated from an interface space-charge storage with capacitive properties, that is, the storage and transport of ions and electrons at the interface of Ti3C2 and LR particles. The modified sample exhibited an initial coulombic efficiency of 94.3 % and 158 mAh g-1 at 5C. Even after 300 cycles at 5C, it retained 87.3 % of its capacity. This novel strategy can serve as a reference for the modification of other electrode materials and can also expand the application of MXene in the field of batteries.