Enhancing Na+ diffusion dynamics and structural stability of O3-NaMn0.5Ni0.5O2 cathode by Sc and Zn dual-substitution

Sc and Zn were introduced into O3-NaMn 0.5 Ni 0.5 O 2 (NaMN) using the combination of solution combustion and solid-state method. The effect of Sc and Zn dual-substitution on Na + diffusion dynamics and structural stability of NaMN was investigated. The physicochemical characterizations suggest that the introduction of Sc and Zn broaden Na + diffusion channels and weaken the Na—O bonds, thereby facilitating the diffusion of sodium ions. Simulations indicate that the Sc and Zn dual-substitution decreases the diffusion barrier of Na-ions and improves the conductivity of the material. The dual-substituted NaMn 0.5 Ni 0.4 Sc 0.04 Zn 0.04 O 2 (NaMNSZ44) cathode delivers impressive cycle stability with capacity retention of 71.2 % after 200 cycles at 1 C and 54.8% after 400 cycles at 5 C . Additionally, the full cell paired with hard carbon anode exhibits a remarkable long-term cycling stability, showing capacity retention of 64.1% after 250 cycles at 1 C . These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na + diffusion dynamics and structural stability of NaMN.