Reconsideration of simultaneous bulk doping and interface structures modification of high-voltage spinel LiNi0.5Mn1.5O4 cathode materials using elemental iodine

The insufficient structural stability of high-voltage spinel cobalt-free LiNi 0.5 Mn 1.5 O 4 (LNMO) throughout the cycling process hinders its widespread application. To address these issues, we incorporate elemental iodine into LNMO during the precursor preparation process using an ethanol-assisted hydrothermal method and successfully modify the bulk and interface coating structure of LNMO-3% I 2 . The incorporation of iodine not only induces the formation of a cavity and fast lithium-ion transfer pathway within the particles but also facilitates the development of a thin LiI coating layer on the surface of cathode materials. Compared with bared LNMO, LNMO-3% I 2 exhibits a capacity retention of 90.31% following 500 cycles at 1C and a capacity retention of 88.74% even following 450cycles at a high-rate of 50C. Furthermore, the cells with LNMO-3% I 2 demonstrate an excellent electrochemical performance under both high temperatures of 40 ℃ and low temperatures of −15 ℃. This study offers valuable insights into the simultaneous optimization of internal and external structures in cathode materials, thereby enhancing the long-term cycling performance of high-voltage lithium-ion batteries.