Extraordinary cycling performance of high-voltage spinel LiNi0.5Mn1.5O4 materials enabled by interfacial engineering via molecular self-assembly

Abstract

High-voltage spinel cobalt-free LiNi_0.5Mn_1.5O₄ (LNMO) materials are considered as promising cathode materials for next-generation high energy-density lithium-ion batteries. However, the application of LNMO materials is hindered by their poor structure stability during cycling, originating from the electrolyte decomposition at high operating voltages and the transition metal dissolution. To address these issues, aliphatic acid molecules were self-assembled on the surface of LNMO for the first time to form an even and robust monomolecular protective layer. The surface modification effectively modulates the interfacial properties and significantly enhances the structure and cycling stability of LNMO materials. A high capacity retention rate of 85.3% was achieved after 1000 cycles at 1C. Furthermore, the generation of cracks and side reactions on the LNMO surface were prevented. This work provides a novel alternative method for the modification of metal-oxide-based cathode materials.