Utilizing the different distribution habit of La and Zr in Li-rich Mn-based cathode to achieve fast lithium-ion diffusion kinetics

Abstract

The commercialization prospect of Li-rich Mn-based (LRM) cathode materials lies in their high energy density (>900 Wh kg−1), but the practical application in many scenarios is hindered by their low intrinsic ionic conductivity. Herein, we increase the ionic conductivity and cycling performance of LRM cathode materials by utilizing the different distribution habit of La3+ and Zr4+. La atoms tend to accumulate on the grain surface, while Zr4+ is likely to be doped into the bulk of LRM cathode, which is confirmed by the theoretical calculation and experimental results. The surface is modified by the island-shaped and conductive LaMnO3+δ (LMO) and La2Zr2O7 (LZO) compounds, constructing a triple-phase interface (TPI) for the rapid lithium-ion diffusion. Meanwhile, the bulk LRM lattices are doped by Zr4+ to stabilize the layered framwork. The modified LRM cathode calcined at 650 °C exhbits a high specific capacity of 192.6 mAh g−1 after 200 cycles at 2C rate with superior Li+ diffusion coefficients and enhanced rate capability. This study sheds light on how to rationally improving the ionic conductivity of LRM cathode for its practical application.