Enhanced High Voltage Stability of Spinel-Type Structured LiNi0.5Mn1.5O4 Electrodes: Targeted Octahedral Crystal Site Modification

High-voltage spinel-type structured LiNi0.5Mn1.5O4 (LNMO) shows promise as a next-generation high-energy-density lithium-ion battery cathode material, however, capacity decay on extended cycling hinders its widespread adoption, underscoring an urgent need for further development. In this work, we introduce Zn at octahedral 16c crystal sites in LNMO with Fd (Formula presented.) m space group to improve rate capability and reduce the rapid capacity decay otherwise experienced during extended cycling. The current work resolves the detailed influence of isolated modification at octahedral 16c crystal sites, unveiling the mechanism for these performance improvements. We show that occupation of Zn at previously empty 16c sites prevents the migration of Ni/Mn to adjacent 16c sites, eliminating transformation to a rock-salt type structured Ni0.25Mn0.75O2 phase above 4.8 V, preventing structure degradation and suppressing voltage polarization. This study provides insights into the fundamental structure-function relationship of the LNMO battery cathode, pointing to pathways for the crystal structure engineering of materials with superior performance.