MoC纳米晶/掺氮多孔碳的结构调控及在锂硫电池中的性能优化  

Structural Optimization of MoC Nanocrystals/Nitrogen-doped Porous Carbon for Enhanced Performance in Lithium-Sulfur Batteries

作　　者：张怿炜 胡仁宗 欧阳柳章 刘军 杨黎春 朱敏 ZHANG Yiwei;HU Renzong;OUYANG Liuzhang;LIU Jun;YANG Lichun;ZHU Min(Guangdong Provincial Key Laboratory of Advanced Energy Storage Materials,School of Materials Science and Engineering,South China University of Technology,Guangzhou 510640,China)

机构地区：[1]华南理工大学材料科学与工程学院,广东省先进储能材料重点实验室,广州510640

出　　处：《材料导报》2025年第6期1-6,共6页Materials Reports

基　　金：广东省基础与应用基础研究基金(2023B1515040011);国家重点研发计划(2022YFB2502003)。

摘　　要：多硫化物(LiPSs)的穿梭效应和迟缓的氧化还原动力学严重阻碍了锂硫电池的发展。鉴于此,本工作制备了一种负载于掺氮多孔碳(NPC)基体上的超细α-MoC纳米晶材料MoC/NPC,并通过调控碳源和钼源比例优化了碳对MoC纳米晶的限域作用。适当的MoC纳米晶尺寸和NPC含量的MoC/NPC对LiPSs具有最强的吸附作用并能够充分暴露亲硫反应活性位点,从而在有效抑制穿梭效应的同时加速Li2 S沉积形核的反应动力学。最优产物MoC/NPC-12(碳源与钼源的质量比为12)用作硫载体且负载量约1.2 mg·cm^(-2)时,表现出良好的倍率性能(4C,634.4 mAh·g^(-1))、高放电比容量(0.2C,1203.9 mAh·g^(-1))以及优异的循环稳定性(1C倍率下循环400次的每圈容量衰减率仅为0.093%)。当硫负载量增加到3.8 mg·cm^(-2)时,MoC/NPC-12@S的初始放电面容量为4.7 mAh·cm^(-2)。本工作为锂硫电池催化剂载体材料的合理设计和优化提供了参考。The shuttle effect of lithium polysulfides(LiPSs)and the sluggish redox kinetics severely hinder the commercial application of lithium-sulfur batteries.The present work made a successful attempt to synthesize an ultrafineα-MoC nanocrystalline material loaded on a nitrogen-doped porous carbon(NPC)substrate,namely MoC/NPC,in which the confinement effect of carbon on MoC nanocrystals could be optimized by con-trolling the ratio of carbon source to molybdenum source.Appropriate MoC nanocrystal diameter and NPC content were found to lead to the stron-gest adsorption for LiPSs and full exposure of sulfur-reactive active sites.This not only effectively suppresses the shuttle effect but also accelerates the reaction kinetics of Li2 S deposition and nucleation.The optimum product,MoC/NPC-12,synthesized with a mass ratio of dicyandiamide(C source)to CdMoO4(Mo source)of 12,demonstrated excellent rate capability(634.4 mAh·g^(-1)at 4C),high discharge capacity(1203.9 mAh·g^(-1)at 0.2C),and exceptional cycle stability(a capacity decay rate of only 0.093%per cycle during 400 cycles at 1C)when loaded with~1.2 mg·cm^(-2)sulfur.And despite a further increment of sulfur loading to 3.8 mg·cm^(-2),an initial areal capacity of MoC/NPC-12@S of 4.7 mAh·cm^(-2)could still be achieved.This work provides valuable insights for the rational design and optimization of catalyst host materials in lithium-sulfur batteries.

关 键 词：锂硫电池 碳化钼 掺氮多孔碳 结构优化 催化转化 多硫化物吸附 

分 类 号：O646[理学—物理化学]