Energy Storage Science and Technology ›› 2020, Vol. 9 ›› Issue (2): 385-391.doi: 10.19799/j.cnki.2095-4239.2020.0006

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Role of Sn doping in layered chromium-based cathode materials for sodium-ion batteries

BIAN Jingjing(), CHU Shiyong, XI Kaiying, GUO Shaohua(), ZHOU Haoshen   

  1. College of Engineering and Applied Sciences, National Laboratory of Solid State Microstructures, Collaborative Innovation Center of Advanced Microstructures, Jiangsu Key Laboratory of Artificial Functional Materials, Nanjing University, Nanjing 210093, Jiangsu, China
  • Received:2020-01-05 Revised:2020-02-06 Online:2020-03-05 Published:2020-03-15
  • Contact: Shaohua GUO E-mail:151190003@mail.nju.edu.cn;shguo@nju.edu.cn

Abstract:

The demand for electrochemical energy storage technology has significantly increased. Currently, the large-scale application of lithium-ion batteries can be attributed to their advantages such as high energy density and large power density; however, limited lithium resources restrict the further development of lithium-ion batteries. The potential applications of sodium-ion batteries are expected to solve this problem. Sodium is abundant, widely distributed, cheap, and has physical and chemical properties similar to those of lithium. Sodium can be used as a substitute for lithium in batteries. A Cr-based layered cathode material has the following advantages: abundant raw materials, easy synthesis methods, and controllable composition. However, when the Cr-based layered cathode material is charged to a relatively high voltage, Cr ions migrate from the transition metal layer to the sodium layer, and the structure of sodium chromate will undergo an irreversible structural transformation, which diminishes the capacity. In this study, a new layered material, Na0.7Cr0.85Sn0.15O2, was fabricated by doping Sn, which has a large ionic radius, into sodium chromate. The structure and electrochemical performance of the materials were systematically investigated. The results show that the doped material has a smooth voltage curve and a stable crystal structure. In addition, doping alleviates the serious attenuation of capacity and improves cycle stability. This new layered chromium-based oxide cathode material is expected to provide a new option for the development of cathode materials for sodium-ion batteries.

Key words: sodium-ion batteries, layered cathode, Cr-based oxide, Sn doping

CLC Number: