Facilitating Layered Oxide Cathodes Based on Orbital Hybridization for Sodium-ion Batteries: Marvelous Air Stability, Controllable High Voltage, And Anion Redox Chemistry.
Xin-Bei JiaJing-Qiang WangYi-Feng LiuYan-Fang ZhuJia-Yang LiYan-Jiang LiShu-Lei ChouYao XiaoPublished in: Advanced materials (Deerfield Beach, Fla.) (2023)
Layered oxides have become the research focus of cathode materials for sodium-ion batteries (SIBs) due to the low cost, simple synthesis process, and high specific capacity. However, the poor air stability, unsteady phase structure under high voltage, and slow anionic redox kinetics hinder their commercial application. In recent years, the concept of manipulating orbital hybridization has been proposed to simultaneously tune the microelectronic structure and modify the surface chemistry environment intrinsically. In this review, the hybridization modes between atoms in 3d/4d transition metal (TM) orbitals and O 2p orbitals near the region of the Fermi energy level (E F ) were summarized based on orbital hybridization theory and first-principles calculations as well as various sophisticated characterizations. Furthermore, the underlying mechanisms are explored from macro-scale to micro-scale, including enhancing air stability, modulating high voltage, and stabilizing anionic redox chemistry. Meanwhile, the origin, formation conditions, and different types of orbital hybridization, as well as its application in layered oxide cathodes are presented, which provide insights into the design and preparation of cathode materials. Ultimately, the main challenges in the development of orbital hybridization and its potential for the production application are also discussed, pointing out the route for high-performance practical sodium layered oxide cathodes. This article is protected by copyright. All rights reserved.