Double Morphology of Co9S8 Coated by N, S Co-doped Carbon as Efficient Anode Materials for Sodium-Ion Batteries

Xuzi Zhang; Chaoqun Shang; Xin Wang; Guofu Zhou

doi:10.1186/s11671-020-3256-8

Double Morphology of Co₉S₈ Coated by N, S Co-doped Carbon as Efficient Anode Materials for Sodium-Ion Batteries

Nanoscale Res Lett. 2020 Jan 22;15(1):19. doi: 10.1186/s11671-020-3256-8.

Authors

Xuzi Zhang¹, Chaoqun Shang^{2

3}, Xin Wang^{4

5}, Guofu Zhou^{1

6}

Affiliations

¹ National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 51000, People's Republic of China.
² National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 51000, People's Republic of China. chaoqun.shang@ecs-scnu.org.
³ International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing, 526000, People's Republic of China. chaoqun.shang@ecs-scnu.org.
⁴ National Center for International Research on Green Optoelectronics, South China Academy of Advanced Optoelectronics, South China Normal University, Guangzhou, 51000, People's Republic of China. wangxin@scnu.edu.cn.
⁵ International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing, 526000, People's Republic of China. wangxin@scnu.edu.cn.
⁶ International Academy of Optoelectronics at Zhaoqing, South China Normal University, Zhaoqing, 526000, People's Republic of China.

Abstract

Co₉S₈ is a potential anode material for its high sodium storage performance, easy accessibility, and thermostability. However, the volume expansion is a great hindrance to its development. Herein, a composite containing Co₉S₈ nanofibers and hollow Co₉S₈ nanospheres with N, S co-doped carbon layer (Co₉S₈@NSC) is successfully synthesized through a facile solvothermal process and a high-temperature carbonization. Ascribed to the carbon coating and the large specific surface area, severe volume stress can be effectively alleviated. In particular, with N and S heteroatoms introduced into the carbon layer, which is conducive to the Na⁺ adsorption and diffusion on the carbon surface, Co₉S₈@NSC can perform more capacitive sodium storage mechanism. As a result, the electrode can exhibit a favorable reversible capacity of 226 mA h g^-1 at 5 A g^-1 and a favorable capacity retention of 83.1% at 1 A g^-1 after 800 cycles. The unique design provides an innovative thought for enhancing the sodium storage performance.

Keywords: Co9S8; N, S co-doping; Node materials; Rate performance.

Abstract

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