Work

MOF-Derived CoOx–CeO2−y/C Heterojunction Synergistically Promotes the Deposition and Decomposition of Li2S in Lithium–Sulfur Batteries

Year: 2025

Type: article

Abstract: The sluggish bidirectional conversion rate between Li2S n (2 ≤ n ≤ 4) and Li2S, coupled with the uncontrolled deposition of Li2S, significantly impedes the realization of high-performance lithium–sulfur batteries (LSBs). In this study, a metal–organic framework was employed as a precursor for the synthesis of a CoO x –CeO2−y /C (0 < x < 3/2, 0 < y < 1/2) heterojunction via pyrolysis, which was subsequently introduced onto the cathode side of the polypropylene (PP) separator in LSBs. The modification of CoO x –CeO2−y /C enhances the kinetics of converting of Li2S n to Li2S during the discharge process. The Tafel slope for the Li2S deposition reaction is reduced to 52.1 mV/dec, representing a 56.6% decrease compared to LSBs with bare PP separator. Conversely, during the charging process, the modification lowers the energy barrier for the Li2S decomposition reaction, with the activation energy reduced to 6.12 kJ/mol, indicating a 70.3% decrease relative to LSBs with PP separator only. Consequently, more Li2S is promoted to undergo decomposition. The CoO x –CeO2−y /C heterojunction facilitates uniform deposition of Li2S, featuring fine particles and a uniform distribution, after brief potentiostatic charging for decomposition, thereby effectively mitigating the deactivation of sulfur species. Thanks to the enhanced bidirectional conversion of lithium polysulfides (LiPS) facilitated by the CoO x –CeO2−y /C modification layer, the (−)Li|CoO x –CeO2−y /C@PP|S(+) coin cell maintains a Coulombic efficiency of 90.4% after 500 cycles at a current density of 1 C, exhibiting a low capacity-decay rate of only 0.081% per cycle, thereby demonstrating excellent long-cycle stability.

Source: Transactions of Tianjin University

DOI: 10.1007/s12209-025-00430-8

Authors: Ke Jia, Yanan Zhang, Rui Zuo, Hongbing Lu, Kemeng Ji, Mingming Chen

Institutions: Tianjin University, Collaborative Innovation Center of Chemical Science and Engineering Tianjin

Language: English

Topic: Advanced Battery Materials and Technologies

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: hybrid

Estimated APC paid: $3,190