Hollow porous carbon nanospheres containing polar cobalt sulfide (Co9S8) nanocrystals as electrocatalytic interlayers for the reutilization of polysulfide in lithium-sulfur batteries

Su Hyun Yang; Jang Min Choi; Rakesh Saroha; Sung Woo Cho; Yun Chan Kang; Jung Sang Cho

doi:10.1016/j.jcis.2023.04.083

Hollow porous carbon nanospheres containing polar cobalt sulfide (Co₉S₈) nanocrystals as electrocatalytic interlayers for the reutilization of polysulfide in lithium-sulfur batteries

J Colloid Interface Sci. 2023 Sep:645:33-44. doi: 10.1016/j.jcis.2023.04.083. Epub 2023 Apr 28.

Authors

Su Hyun Yang¹, Jang Min Choi², Rakesh Saroha², Sung Woo Cho², Yun Chan Kang³, Jung Sang Cho⁴

Affiliations

¹ Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, Republic of Korea.
² Department of Engineering Chemistry, Chungbuk National University, Chungbuk 361-763, Republic of Korea.
³ Department of Materials Science and Engineering, Korea University, Anam-Dong, Seongbuk-Gu, Seoul 136-713, Republic of Korea. Electronic address: yckang@korea.ac.kr.
⁴ Department of Engineering Chemistry, Chungbuk National University, Chungbuk 361-763, Republic of Korea. Electronic address: jscho@cbnu.ac.kr.

PMID: 37146377
DOI: 10.1016/j.jcis.2023.04.083

Abstract

Hypothesis: The introduction of functional interlayers for efficient anchoring of lithium polysulfides has received significant attention worldwide.

Experiments: A facile wet-chemical method was adopted to obtain hollow porous carbon nanospheres (HPCNSs) impregnated with metallic and polar cobalt sulfide (Co₉S₈) nanocrystals (abbreviated as "Co₉S₈@HPCNS"). The prepared nanocrystals were employed as electrocatalytic interlayers via separator coating for the efficient capture and reutilization of polysulfide species in Li-S batteries. The HPCNSs were synthesized via the polymerization method followed by carbonization and template removal. The Co₉S₈ nanocrystals were impregnated inside the HPCNSs, followed by heat treatment in a reducing atmosphere.

Findings: The porous structure of the CNS enables the efficient percolation of the electrolyte, in addition to accommodating unwanted volume fluctuations during redox processes. Furthermore, the metallic Co₉S₈ nanocrystals improve the electronic conductivity and enhance the polarity of the CNS towards the polysulfide. Correspondingly, the Li-S cells featuring Co₉S₈@HPCNS as electrocatalytic interlayers and regular sulfur (S) electrodes display improved electrochemical performance such as reasonable rate performance and prolonged cycling stability at different current rates (0.1, 0.5, and 1.0 C). Therefore, we anticipate that the rational design strategy proposed herein will provide significant insights into the synthesis of advanced materials for various energy storage applications.

Keywords: Functional interlayer; Hollow carbon nanosphere; Lithium–sulfur battery; Metal sulfide nanocrystal; Polysulfide capturing.