中國有色金屬學報(英文版)
Transactions of Nonferrous Metals Society of China
| Vol. 34 No. 10 October 2024 |
（1. State Key Laboratory of Powder Metallurgy, Central South University, Changsha 410083, China;
2. Vital Material Co., Ltd., Guangzhou 510623, China;
3. The 48th Research Institute of China Electronics Technology Group Corporation, Changsha 410111, China;
4. Wuhan Zhongyuan Changjiang Technology Development Co., Ltd., Wuhan 430090, China）
Abstract:Sc and Zn were introduced into O3-NaMn0.5Ni0.5O2 (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 NaMn0.5Ni0.4Sc0.04Zn0.04O2 (NaMNSZ44) cathode delivers impressive cycle stability with capacity retention of 71.2 % after 200 cycles at 1C and 54.8% after 400 cycles at 5C. 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 1C. These results demonstrate that Sc and Zn dual-substitution is an effective strategy to improve the Na+ diffusion dynamics and structural stability of NaMN.
Key words: layered oxide cathode; Sc and Zn dual-substitution; structural stability; Na+ diffusion dynamics
