Pinning Effect Enhanced Structural Stability toward a Zero-Strain Layered Cathode for Sodium-Ion Batteries

Shiyong Chu; Chunchen Zhang; Hang Xu; Shaohua Guo; Peng Wang; Haoshen Zhou

doi:10.1002/anie.202100917

Pinning Effect Enhanced Structural Stability toward a Zero-Strain Layered Cathode for Sodium-Ion Batteries

Angew Chem Int Ed Engl. 2021 Jun 7;60(24):13366-13371. doi: 10.1002/anie.202100917. Epub 2021 May 10.

Authors

Shiyong Chu¹, Chunchen Zhang¹, Hang Xu¹, Shaohua Guo¹, Peng Wang¹, Haoshen Zhou^{1

2}

Affiliations

¹ College of Engineering and Applied Sciences, Jiangsu Key Laboratory of Artificial Functional Materials, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing, 210093, China.
² Energy Technology Research Institute, National Institute of Advanced Industrial Science and Technology (AIST), Umezono 1-1-1, Tsukuba, 305-8568, Japan.

PMID: 33797136
DOI: 10.1002/anie.202100917

Abstract

Layered oxides as the cathode materials of sodium-ion batteries are receiving extensive attention due to their high capacity and flexible composition. However, the layered cathode tends to be thermodynamically and electrochemically unstable during (de)sodiation. Herein, we propose the pinning effect and controllable pinning point in sodium storage layered cathodes to enhance the structural stability and achieve optimal electrochemical performance. 0 %, 2.5 % and 7.3 % transition-metal occupancies in Na-site as pinning points are obtained in Na_0.67 Mn_0.5 Co_0.5-x Fe_x O₂ . 2.5 % Na-site pinned by Fe³⁺ is beneficial to restrain the potential slab sliding and enhance the structural stability, resulting in an ultra-low volume variation of 0.6 % and maintaining the smooth two-dimensional channel for Na-ion transfer. The Na_0.67 Mn_0.5 Co_0.4 Fe_0.1 O₂ cathode with the optimal Fe³⁺ pinning delivers outstanding cycle performance of over 1000 cycles and superior rate capability up to 10 C.

Keywords: layered cathodes; pinning effect; sodium-ion batteries; structural stability; zero strain.