Improving Electrochemical Performance of LiNi0.5Mn1.5O4 Cathode Material by Al/Co Co-doping

Spinel LiNi 0.5 Mn 1.5 O 4 is a promising high-voltage cathode material for lithium-ion batteries, but its application is limited by Mn dissolution and poor high-temperature stability. Herein, Al-doped, Co-doped, and Al/Co codoped LNMO materials were synthesized via a high-temperature solid-state method. All samples retain the spinel structure (Fd m), while Al and Co doping reduces Mn 3+ content, induces lattice contraction, and enhances structural stability. The Al/Co codoped LNMO exhibits reduced polarization, enhanced Li + diffusion kinetics, and improved cycling and rate performance. Notably, it retains 96.7% of its initial capacity after 100 cycles at 50°C and 1°C, accompanied by suppressed Mn dissolution. These results demonstrate that Al/Co codoping is an effective strategy to improve the structural and electrochemical stability of LNMO under high-temperature conditions. Graphical Al/Co codoping reduces the Mn³ + content and suppresses Mn dissolution, thereby stabilizing the crystal structure and electrode/electrolyte interface, significantly enhancing the cycling stability and capacity retention of LNMO at elevated temperatures.