F-doped Co-free LiNixMn1-xO2 (0.7 ≤ x ≤ 0.9) cathodes for ameliorating electrochemical performance of Li-ion batteries

Ni-rich LiNiCoMnO2 cathodes, which exhibit high energy densities and layered structures, have been studied For Li-ion batteries (LIBs) with high capacities and excellent stabilities. However, the high cost and price fluctuation of Co as the main element in the cathodes remain severe issues for the stable development of LIBs. Therefore, in this study, F-doped Co-free Ni-rich LiNixMn1-xO2 (0.7 ≤ x ≤ 0.9) cathodes were prepared for high-performance LIBs. With increasing Ni content, the undoped Ni-rich LiNixMn1-xO2 cathodes exhibited increased discharge capacities and decreased stabilities. In contrast, the F-doped Ni-rich LiNixMn1-xO2 cathodes delivered higher cycle retentions at 0.5 C for 100 cycles compared to the undoped cathodes. In addition, the F doping of Ni-rich LiNixMn1-xO2 cathodes can facilitate Li-ion diffusion, retaining their reversibility and high capacities at high current densities.