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 issue for the stable development of LIBs. Therefore, in this study, F-doped Co-free Ni-rich LiNi_xMn_1-xO₂ (0.7 ≤ x ≤ 0.9) cathodes were prepared for high-performance LIBs. With increasing Ni content, the undoped Ni-rich LiNi_xMn_1-xO₂ cathodes exhibited increased discharge capacities and decreased stabilities. In contrast, the F-doped Ni-rich LiNi_xMn_1-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 LiNi_xMn_1-xO₂ cathodes can facilitate Li-ion diffusion, retaining their reversibility and high capacities at high current densities.