Highly Active and Stable Li2S−Cu Nanocomposite Cathodes Enabled by Kinetically Favored Displacement Interconversion between Cu2S and Li2S. (15th June 2022)

• Record Type: Journal Article
• Authors: Tan, Lulu; Li, Anran; Yang, Yusi; Zhang, Jianwen; Niu, Xiaogang; Li, Nan; Liu, Limin; Guo, Lin; Zhu, Yujie
• Is Part Of: Angewandte Chemie. Volume 134:Number 31(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-06-15
• Subjects: Displacement Reactions -- Li2S Cathode Materials -- Li2S-Graphite Full-Cell -- Reduced Activation Potential; Chemistry -- Periodicals; 540
• DOI: 10.1002/ange.202206012
• Languages: English
• ISSNs: 0044-8249

Abstract

Abstract: The high activation barrier, inferior rate performance, and short cycling life severely constrain the practical applications of the high‐capacity Li2 S cathode. Herein, we fabricate a Li2 S−Cu nanocomposite with a drastically reduced activation potential, fast rate capability, and extraordinary cycling stability even under a practically relevant areal capacity of 2.96 mAh cm −2 . Detailed experimental investigations aided by theoretical calculations indicate that instead of converting to S8 via troublesome soluble lithium polysulfides, Li2 S is thermodynamically and kinetically more favorable to react with Cu by the displacement reaction, which alters the redox couple from Li2 S/S to Cu/Cu2 S, leading to the excellent electrochemical performance. Moreover, the stability of the composite is demonstrated in the full‐cell configuration consisting of commercial graphite anodes. This work provides an innovative and effective approach to realize highly activated and stable Li2 S cathode materials. Abstract : A nanostructured Li2 S−Cu composite is fabricated and it is demonstrated that Cu progressively participates in the redox processes and fundamentally alters the redox couple from anion‐type Li2 S/S to cation‐type Cu/Cu2 S, which leads to a drastically reduced activation potential (2.35 V vs. Li + /Li), superior rate capability, and stable long‐term cycling performance.