Enlarged interlayer spacing and enhanced capacitive behavior of a carbon anode for superior potassium storage

Xiaodong Shi; Yida Zhang; Guofu Xu; Shan Guo; Anqiang Pan; Jiang Zhou; Shuquan Liang

doi:10.1016/j.scib.2020.07.001

Enlarged interlayer spacing and enhanced capacitive behavior of a carbon anode for superior potassium storage

Sci Bull (Beijing). 2020 Dec 15;65(23):2014-2021. doi: 10.1016/j.scib.2020.07.001. Epub 2020 Jul 3.

Authors

Xiaodong Shi¹, Yida Zhang², Guofu Xu³, Shan Guo¹, Anqiang Pan³, Jiang Zhou⁴, Shuquan Liang⁵

Affiliations

¹ School of Materials Science and Engineering, Central South University, Changsha 410083, China.
² National Synchrotron Radiation Laboratory (NSRL), University of Science and Technology of China, Hefei 230029, China.
³ School of Materials Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China.
⁴ School of Materials Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China. Electronic address: zhou_jiang@csu.edu.cn.
⁵ School of Materials Science and Engineering, Central South University, Changsha 410083, China; Key Laboratory of Electronic Packaging and Advanced Functional Materials of Hunan Province, Central South University, Changsha 410083, China. Electronic address: lsq@csu.edu.cn.

PMID: 36659060
DOI: 10.1016/j.scib.2020.07.001

Abstract

Potassium-ion batteries (PIBs) hold great potential as an alternative to lithium-ion batteries due to the abundant reserves of potassium and similar redox potentials of K⁺/K and Li⁺/Li. Unfortunately, PIBs with carbonaceous electrodes present sluggish kinetics, resulting in unsatisfactory cycling stability and poor rate capability. Herein, we demonstrate that the synergistic effects of the enlarged interlayer spacing and enhanced capacitive behavior induced by the co-doping of nitrogen and sulfur atoms into a carbon structure (NSC) can improve its potassium storage capability. Based on the capacitive contribution calculations, electrochemical impedance spectroscopy, the galvanostatic intermittent titration technique, and density functional theory results, the NSC electrode is found to exhibit favorable electronic conductivity, enhanced capacitive adsorption behavior, and fast K⁺ ion diffusion kinetics. Additionally, a series of ex-situ characterizations demonstrate that NSC exhibits superior structural stability during the (de)potassiation process. As a result, NSC displays a high reversible capacity of 302.8 mAh g^-1 at 0.1 A g^-1 and a stable capacity of 105.2 mAh g^-1 even at 2 A g^-1 after 600 cycles. This work may offer new insight into the effects of the heteroatom doping of carbon materials on their potassium storage properties and facilitate their application in PIBs.

Keywords: Capacitive behavior; Carbon interlayer; Co-doping of nitrogen and sulfur atoms; Potassium-ion batteries; Synergistic effects.