Mitigating the Kinetic Hysteresis of Co‐Free Ni‐Rich Cathodes via Gradient Penetration of Nonmagnetic Silicon

Abstract

AbstractCo‐free Ni‐rich layered oxides are considered a promising cathode material for next‐generation Li‐ion batteries due to their cost‐effectiveness and high capacity. However, they still suffer from the practical challenges of low discharge capacity and poor rate capability due to the hysteresis of Li‐ion diffusion kinetics. Herein, based on the regulation of the lattice magnetic frustration, the Li/Ni intermixing defects as the primary origin of kinetic hysteresis are radically addressed via the doping of the nonmagnetic Si element. Meanwhile, by adopting gradient penetration doping, a robust Si−O surface structure with reversible lattice oxygen evolution and low lattice strain is constructed on Co‐free Ni‐rich cathodes to suppress the formation of surface dense barrier layer. With the remarkably enhanced Li‐ion diffusion kinetics in atomic and electrode particle scales, the as‐obtained cathodes (LiNixMn1−xSi0.01O2, 0.6≤x≤0.9) achieve superior performance in discharge capacity, rate capability, and durability. This work highlights the coupling effect of magnetic structure and interfacial chemicals on Li‐ion transport properties, and the concept will inspire more researchers to conduct an intensive study.