Medium-entropy Li1.2Ni0.13Co0.13Mn0.54O2 cathode with enhanced electrochemical performance by microstructural stabilization and surface modification

Lithium-rich layered oxides have gained considerable attention as cathode materials for lithium-ion batteries due to their high energy density . However, their insufficient structural stability results in rapid capacity fading and low initial Coulombic efficiency, hindering practical applications. In this study, we successfully synthesized medium-entropy Li 1.2 Ni 0.13 Co 0.13 Mn 0.54 O 2 (LMNCO) through co-doping with Mg, Al, and La. The optimized Li 1.2 Ni 0.12 Co 0.12 Mn 0.53 Mg 0.01 Al 0.01 La 0.01 O 2 exhibited outstanding electrochemical performance, including a high initial reversible capacity of 272 mAh g −1 , an initial Coulombic efficiency of 82.2 %, and a capacity retention of 83 % after 100 cycles. These improvements can be attributed to the microstructural advantages, including optimized lattice parameters , enhanced lattice oxygen stability, and strengthened transition metal‑oxygen bonds. Density functional theory (DFT) calculations further confirmed that Mg, Al, and La co-doping increased the adsorption energy (−3.12 eV) and the number of transferred electrons (0.87 e) compared with samples doped with each element individually. Meanwhile, the p-band center energy level of oxygen at the lithium adsorption site increased, further verifying that medium entropy facilitated the enhancement of electrochemical performance. The co-doping method suggests a promising strategy to develop cathode materials with enhanced capacity and stability, designed for the next generation of lithium-ion batteries. • Medium-entropy Li 1.2 Ni 0.12 Co 0.12 Mn 0.53 Mg 0.01 Al 0.01 La 0.01 O 2 is synthesized by co-doping. • Co-doping optimizes microstructure and increases entropy for better Li + migration. • Li 2 WO 4 -coated D-LMNCO exhibits enhanced electrochemical performance. • DFT calculations demonstrate the advantageous effects of co-doping on adsorption energy and electrochemical performance.