Enhancing structure and cycling stability of single crystal LiNi0.5Mn1.5O4 cathode via multifunctional MXene surface modification

Abstract

Single crystal LiNi0.5Mn1.5O4 (LNMO) has gained increasing attention due to its cobalt-free composition, low rolling resistance, and high energy density. However, its high voltage operating range renders it susceptible to electrolyte dissolution and side reactions, limiting its large-scale practical application as it exhibits poor cycling stability and rate performance. In this study, a novel composite material, LNMO@MXene, was developed by electrostatic self-assembly of single or few-layered MXene (Ti3C2Tx) onto the surface of LNMO. Among them, LNMO coated with 3 wt% MXene exhibited a discharge capacity of up to 130.86 mAh·g−1 at 1C, and a specific capacity of 109.80 mAh·g−1 at 5C after 500 cycles. After 200 cycles at 55 °C, the specific capacity was 114.4 mAh·g−1 with a retention rate as high as 86.99 %. The electrostatic self-assembly of MXene is a simple and effective coating strategy, which creates a conductive network, increases the capacity through Li+ intercalation, and forms a protective cathode electrolyte interphase (CEI) layer to inhibit interfacial side reactions. The synergistic effect between MXene and LNMO enhances the electrochemical performance of LNMO materials. This coating strategy can also be applied to the design of other cathode materials.