Preparation and characterization of lithium-rich high-entropy disordered rock-salt cathodes for lithium-ion batteries

Disordered rock-salt (DRX) materials represent a highly promising class of high-energy-density cathode materials for lithium-ion batteries, though their rate performance remains suboptimal. Addressing this limitation, this study employs a high-entropy strategy to enhance the electrochemical performance of such materials. We successfully synthesized the low-entropy DRX cathode Li_1.2Mn_0.4Ti_0.4O₂ (TM2), as well as the high-entropy DRX structure cathodes Li_1.2(Mn2+_0.1Fe3+_0.1Mn3+_0.1Cr3+_0.1Ti4+_0.15Nb5+_0.22)O₂ (TM6) and Li_1.2(Mn2+_0.1Fe3+_0.1Mn3+_0.1Cr3+_0.1Ti4+_0.15Nb5+_0.18)O_1.8F_0.2 (TM6F). GITT analysis reveals diffusion coefficients ranging from 10−12-10−11cm2s−1. At 400 mA g−1, TM6F/C achieves a discharge specific capacity of 205 mAh g−1, significantly surpassing TM2/C (126 mAh g−1) and TM6/C (191 mAh g−1). TM2/C, TM6/C, and TM6F/C demonstrate capacity retention rates of 26.86%, 33.85%, and 34.13%, respectively, after 50 cycles at 40 mA g−1. At the open circuit potential, the charge transfer resistance (R_ct) of TM6F/C (115.5 Ω) is lower than that of TM6/C (132.8 Ω). This work demonstrates the advantages of high-entropy design and anion regulation in developing high-performance DRX cathode materials.