催化学报

催化学报 ›› 2027, Vol. 92: 420-427.DOI: 10.1016/S1872-2067(26)65250-3

• 论文 • 上一篇    下一篇

用于先进锂硫电池的单原子修饰S-MXene催化剂: 多硫化物转化和Li2S分解动力学的协同优化

范稞a,*(), 朱雨晴a, 应亦然b,*()   

  1. a 安徽大学材料科学与工程学院, 安徽合肥 230601
    b 西北工业大学材料学院, 凝固技术全国重点实验室, 纳米能源材料研究中心, 陕西西安 710072
  • 收稿日期:2026-04-07 接受日期:2026-05-09 出版日期:2027-01-02 发布日期:2026-10-30
  • 通讯作者: *电子信箱: kefan@ahu.edu.cn (范稞),
    yiranying@nwpu.edu.cn (应亦然).
  • 基金资助:
    国家自然科学基金(22502157);中央高校基本科研业务费(D5000240296)

Bidirectional catalysis of polysulfides and Li2S redox kinetics by single-atom modified S-MXene for advanced Li-S batteries

Ke Fana,*(), Yuqing Zhua, Yiran Yingb,*()   

  1. a School of Materials Science and Engineering, Anhui University, Hefei 230601, Anhui, China
    b State Key Laboratory of Solidification Processing, Center for Nano Energy Materials, School of Materials Science and Engineering, Northwestern Polytechnical University and Shaanxi Joint Laboratory of Graphene (NPU), Xi’an 710072, Shaanxi, China
  • Received:2026-04-07 Accepted:2026-05-09 Online:2027-01-02 Published:2026-10-30
  • Contact: *E-mail: kefan@ahu.edu.cn (K. Fan),
    yiranying@nwpu.edu.cn (Y. Ying).
  • Supported by:
    National Natural Science Foundation of China(22502157);Fundamental Research Funds for the Central Universities(D5000240296)

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摘要：

锂硫电池面临着多硫化物“穿梭效应”以及硫还原反应(SRR)和Li2S分解动力学缓慢的核心问题. 目前的硫宿主材料表面活性位点调控不足、多硫化物吸附与催化转化难以协同优化, 制约了其电化学性能的进一步提升. 开发可高效锚定多硫化锂、加速Li2S氧化还原的催化剂, 是突破锂硫电池性能瓶颈的核心方向. 在传统研究中, MXene可作为硫宿主材料, 缓解这些瓶颈问题, 但研究多集中于碳化物类型, 对氮化物MXene的探索相对有限.

为解决V2N MXene作为硫宿主材料时对硫物种吸附过强和Li2S分解能垒高的问题, 本文提出了在S官能团化的V2NS2表面锚定单个3d过渡金属原子的策略, 构建了V2NS2-T (T = Sc~Zn)单原子催化剂体系, 并探究了单原子修饰在锂硫电池双功能催化(放电过程催化硫还原反应SRR, 充电过程催化Li2S分解)中的调控作用, 揭示了催化剂的构效关系. 采用密度泛函理论计算系统性地评估了所设计的V2NS2-T体系的各项性能. 首先确认了所有体系的热力学、电化学稳定性以及优异的金属导电性. 在锚定能力方面, 计算显示所有V2NS2-T体系对长链多硫化物的吸附能均远低于它们与电解液分子(DOL/DME)的结合能, 表明催化剂能有效抑制穿梭效应. 在SRR中, V2NS2-Cr和V2NS2-Zn表现出最优异的催化活性, 其速率决定步骤的自由能变ΔG分别低至0.15和0.17 eV; 对于充电过程中关键的Li2S分解反应, 发现V2NS2-Cr, V2NS2-Fe和V2NS2-Mn可将分解能垒从原始V2NS2的0.66 eV显著降低至0.27, 0.27和0.28 eV. 同时, Li+在这些表面的扩散能垒均很低, 有利于充电过程. 在所有体系中, V2NS2-Cr是一种优异的双功能催化剂, 它在抑制多硫化物穿梭、加速放电和充电动力学方面均表现突出. 其反应机理源于单原子修饰对基底电子结构的调控. 态密度分析显示, Cr单原子的引入在费米能级附近产生局域的杂质态(主要来自Cr 3d轨道), 提供了额外的电子导电通道, 从而优化了反应中间体的吸附强度, 降低了硫还原反应和Li2S分解的动力学能垒. 此外, 本文建立了一个有效的能量描述符ΔE(*LiS), 大大降低了Li2S分解能垒的计算成本, 提升了催化剂预测效率.

综上, 本文通过理论计算系统地证明了在氮化物V2NS2 MXene上锚定单原子是调控其双功能催化性能的有效策略, 发现了性能卓越的V2NS2-Cr候选材料, 并建立了一个高效的能量描述符, 为未来高通量设计和筛选高性能锂硫电池正极催化剂提供了重要的理论框架.

关键词: 锂硫电池, 单原子催化剂, MXene, 多硫化物转化, 分解动力学

Abstract:

The development of highly efficient catalysts for anchoring lithium polysulfides (LiPSs) and facilitating the Li2S redox process is crucial for advancing high-performance lithium-sulfur (Li-S) batteries. In this work, we introduce single-atom 3d transition metals anchored on V2NS2 MXene substrates (V2NS2-T, where T = Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, and Zn) as host materials to enhance the electrochemical behavior of Li-S batteries. By using density functional theory calculations, we demonstrate that all ten systems exhibit moderate adsorption strength toward LiPSs, effectively suppressing their dissolution and shuttling. Among them, V2NS2-Cr and V2NS2-Zn show the lowest Gibbs free energy barriers for the sulfur reduction reaction during discharge (0.15 and 0.17 eV, respectively). In addition, three V2NS2-T configurations exhibit impressive catalytic activity toward Li2S decomposition during charging, reducing the energy barrier from 0.66 eV (pristine V2NS2) to 0.27 eV (V2NS2-Cr), 0.27 eV (V2NS2-Fe), and 0.28 eV (V2NS2-Mn). Based on these results, the V2NS2-Cr monolayer is identified as a promising sulfur host material because of its fast charge/discharge kinetics. Moreover, we develop an energy-based ΔE descriptor to reduce the computational cost associated with determining Li2S decomposition barriers. This work provides valuable insights for designing high-potential MXene-based sulfur hosts and other two-dimensional conductive anchoring materials for Li-S batteries.

Key words: Li-S batteries, Single-atom catalyst, Mxene, Polysulfides conversion, Decomposition kinetics