Thermodynamically Stable Dual‐Modified LiF&FeF3 layer Empowering Ni‐Rich Cathodes with Superior Cyclabilities

Abstract

AbstractPushing the limit of cutoff potentials allows nickel‐rich layered oxides to provide greater energy density and specific capacity whereas reducing thermodynamic and kinetic stability. Herein, a one‐step dual‐modified method is proposed for in situ synthesizing thermodynamically stable LiF&FeF3 coating on LiNi0.8Co0.1Mn0.1O2 surfaces by capturing lithium impurity on the surface to overcome the challenges suffered. The thermodynamically stabilized LiF&FeF3 coating can effectively suppress the nanoscale structural degradation and the intergranular cracks. Meanwhile, the LiF&FeF3 coating alleviates the outward migration of Oα− (α<2), increases oxygen vacancy formation energies, and accelerates interfacial Li+ diffusion. Benefited from these, the electrochemical performance of LiF&FeF3 modified materials is improved (83.1% capacity retention after 1000 cycles at 1C), even under exertive operational conditions of elevated temperature (91.3% capacity retention after 150 cycles at 1C). This work demonstrates that the dual‐modified strategy can simultaneously address the problems of interfacial instability and bulk structural degradation and represents significant progress in developing high‐performance lithium‐ion batteries (LIBs).