A Novel Scheme to Improve the Stability of Conventional‐Concentration Electrolyte at High Voltage

Abstract It is well‐known that conventional‐concentration electrolytes (CCEs) will undergo serious oxidative decomposition in high‐voltage lithium‐ion batteries, while high‐concentration electrolytes (HCEs) have good oxidation stability. However, HCEs are difficult to scale‐up for industrial applications due to their high viscosity and cost. Herein, based on the anti‐oxidation mechanism of HCE, a novel scheme to improve the stability of CCE at high voltage was proposed. By means of magnetron sputtering LiF on LiNi 0.5 Mn 1.5 O 4 surface and introducing LiPO 2 F 2 additive, a stable cathode electrolyte interphase (CEI) film is constructed in CCE. AFM results show that the constructed CEI film in CCE has better mechanical strength and adhesion than that formed by HCE. Moreover, the battery performance with the constructed CEI film in CCE, which affords high stability at high voltage, fast‐charging kinetics, and improved cycling stability (135 mAh g −1 after 200 cycles), is comparable to that with HCE.