Improving the Cyclic Stability of LiNi0.5Mn1.5O4 Cathode by Modifying the Interface Film with 8‐Hydroxyquinoline

Abstract 8‐Hydroxyquinoline (8‐HDQN) is used as a bifunctional film‐forming additive to improve the capacity retention of Li/LiNi 0.5 Mn 1.5 O 4 (LNMO) cell. Electrochemical analysis and ex‐situ analysis prove that 8‐HDQN can preferentially oxidize on the surface LNMO cathode to modify the Cathode Electrolyte Interface (CEI) film. The modified film effectively reduces the oxidation reaction of the electrolyte and the increase of polarization during the cycle. The CEI film derived from 8‐HDQN also inhibits the dissolution of transition metals ions from the LNMO electrode, and reduces the self‐discharge of the Li/ LNMO cell. Moreover, 8‐HDQN can also reduce the side reaction of PF 5 by coordination with PF 5 to improve the thermal stability of the electrolyte.