Improving electrochemical performance of LiNi0.5Mn1.5O4 positive electrodes via regulated cathode electrolyte interphase

•A robust SmF3 surface layer is successfully introduced to the LiNi0.5Mn1.5O4 electrode via a facile sol-gel process.•The surface modification strategy is confirmed to effectively stabilize LiNi0.5Mn1.5O4 via modulating cathode electrolyte interphase.•This surface regulation strategy endows the high-voltage spinel material with a more uniform and stable cathode electrolyte interphase as well as a faster Li+transfer kinetics, revealing fascinating electrochemical as well as the surface structural properties.