Journal Article

Unblocking Oxygen Charge Compensation for Stabilized High‐Voltage Structure in P2‐Type Sodium‐Ion Cathode

Yao, Zhenpeng, Huang, Yalan, Ren, Yang, Lan, Si, Chen, Yanan, Zhang, Jian, Sun, Cheng‐Jun, Fan, Longlong, Li, Cheng Chao, Xia, Hui, Liu, Qi, Gu, Lin, Zhou, Hua, Zhu, He, Wiaderek, Kamila M., Zhu, Hekang

2022

Overview

Layered transition‐metal (TM) oxides are ideal hosts for Li+ charge carriers largely due to the occurrence of oxygen charge compensation that stabilizes the layered structure at high voltage. Hence, enabling charge compensation in sodium layered oxides is a fascinating task for extending the cycle life of sodium‐ion batteries. Herein a Ti/Mg co‐doping strategy for a model P2‐Na2/3Ni1/3Mn2/3O2 cathode material is put forward to activate charge compensation through highly hybridized O2pTM3d covalent bonds. In this way, the interlayer OO electrostatic repulsion is weakened upon deeply charging, which strongly affects the systematic total energy that transforms the striking P2–O2 interlayer contraction into a moderate solid‐solution‐type evolution. Accordingly, the cycling stability of the codoped cathode material is improved superiorly over the pristine sample. This study starts a perspective way of optimizing the sodium layered cathodes by rational structural design coupling electrochemical reactions, which can be extended to widespread battery researches. Here a Ti/Mg codoping strategy for a model P2‐Na2/3Ni1/3Mn2/3O2 (NNM) cathode material is proposed to activate oxygen charge compensation at high voltage. In this way, the interlayer OO electrostatic repulsion is released, which modifies the P2–O2 transition into a moderate solid‐solution type evolution, and therefore remarkably enhances the cycling performance of the P2‐type NNM layered cathode.

• Publisher: John Wiley & Sons, Inc,Wiley Blackwell (John Wiley & Sons),John Wiley and Sons Inc,Wiley
• Subject: Alternative energy / battery NMC / ENERGY STORAGE / high-voltage structural stability / in situ synchrotron characterizations / layered transition-metal oxide cathodes / Lithium / Morphology / oxygen charge compensation / Phase transitions / Sodium / sodium-ion battery / Spectrum analysis