Affiliation:
1. Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and Technology State Key Laboratory for Advanced Metals and Materials University of Science and Technology Beijing Beijing 100083 China
2. Tianjin Key Laboratory for Photoelectric Materials and Devices School of Materials Science and Engineering Tianjin University of Technology Tianjin 300384 China
3. Key Laboratory of Advanced Energy Materials Chemistry (Ministry of Education) Nankai University Tianjin 300071 China
Abstract
AbstractNa+/vacancy ordering in sodium‐ion layered oxide cathodes is widely believed to deteriorate the structural stability and retard the Na+ diffusion kinetics, but its unexplored potential advantages remain elusive. Herein, we prepared a P2‐Na0.8Cu0.22Li0.08Mn0.67O2 (NCLMO‐12 h) material featuring moderate Na+/vacancy and transition‐metal (TM) honeycomb orderings. The appropriate Na+/vacancy ordering significantly enhances the operating voltage and the TM honeycomb ordering effectively strengthens the layered framework. Compared with the disordered material, the well‐balanced dual‐ordering NCLMO‐12 h cathode affords a boosted working voltage from 2.85 to 3.51 V, a remarkable ~20 % enhancement in energy density, and a superior cycling stability (capacity retention of 86.5 % after 500 cycles). The solid‐solution reaction with a nearly “zero‐strain” character, the charge compensation mechanisms, and the reversible inter‐layer Li migration upon sodiation/desodiation are unraveled by systematic in situ/ex situ characterizations. This study breaks the stereotype surrounding Na+/vacancy ordering and provides a new avenue for developing high‐energy and long‐durability sodium layered oxide cathodes.
Funder
National Natural Science Foundation of China
National Program for Support of Top-notch Young Professionals
State Key Laboratory for Advanced Metals and Materials
Higher Education Discipline Innovation Project