Although they possess a high working voltage and environmental compatibility, and are low in cost with abundant resources, the poor cycling performance and rapid capacity attenuation of LiMn2O4 cathodes at high temperature restrict their extensive application. In this study, LiMn2O4 materials are synthesized by a simple rheology-assisted solid-phase method using citric acid as an additive. The citric acid improves the uniformity of the mixed raw materials, resulting in a reduction in particle agglomeration. Consequently, the synthesized LiMn2O4 shows an initial capacity of 117.4 mA h g−1 with a capacity retention of 79.50% at 2C after 300 cycles and 54.78% of the initial discharge capacity at 20C. This work provides a strategy for modifying multicomponent transition metal oxides for advanced lithium-ion batteries.
Spinel LiNi 0.5 Mn 1.5 O 4 (LNMO) has gained significant attention as a promising cathode material for lithium-ion batteries due to its high working voltage (>4.7 V) and energy density . However, challenges such as electrolyte decomposition-induced material interface erosion and transition metal dissolution under high operating voltage hinder its commercial use. In this study, a thin and uniform Sm 2 O 3 layer has been successfully deposited on the surface of LNMO using a wet chemical method . A comprehensive investigation of surface morphology , crystal structure, and electrochemical performance of the modified LNMO is conducted. The results demonstrate that the Sm 2 O 3 surface modification acts as a robust multifunctional protective layer, effectively shielding against hydrofluoric acid-induced chemical attack and enhancing the migration efficiency of lithium ions . Notably, the capacity retention rate of LNMO@Sm 2 O 3 (3 wt%) remains up to 88 % after 280 cycles, significantly surpassing the uncoated counterpart. The coated material exhibits a capacity of 114 mAh g −1 even under 10 C rate conditions. Moreover, the AC impedance values and manganese dissolution of the modified material in the organic electrolyte are considerably lower than those of the uncoated counterpart. Theoretical calculations strongly support the experimental findings, revealing higher Mn vacancy formation energy and density of states at the Fermi energy level for the Sm 2 O 3 -modified electrodes. This research contributes to the field of surface modification and paves the way for further enhancements in the electrochemical performance of other high-voltage manganese-based lithium-ion batteries (LIBs).
危险品化学品经营许可证（带存储）