金属氧化物/炭复合材料抑制锂硫电池穿梭效应的研究进展

A review of the use of metal oxide/carbon composite materials to inhibit the shuttle effect in lithium-sulfur batteries

锂硫电池因理论能量密度高、生产成本低和环境友好等优点被认为是最有前途的下一代电化学储能装置之一。然而,硫和硫化锂的低导电性、严重的穿梭效应和缓慢的反应动力学等问题阻碍了锂硫电池的大规模商业化应用。炭材料因高比表面积,良好导电性与结构多样性而备受关注,然而非极性炭材料难以与极性多硫化物紧密结合,导致活性材料大量损失和严重的穿梭效应。金属氧化物具有极性强和丰富吸附位点的优点,将过渡金属氧化物与炭材料结合,有助于增强对多硫化物的化学吸附和电化学反应活性。本文首先介绍了锂硫电池的基本原理和存在的主要问题,然后讨论了近年来过渡金属氧化物/炭复合材料在合成方法和结构设计(1D,2D,3D)方面的研究进展。此外,详细介绍了异质结构设计、空位工程和晶面调控策略的代表性工作并讨论了其机理。最后,对过渡金属氧化物/炭复合材料用于锂硫电池中的发展进行了总结和展望。

Lithium-sulfur(Li-S)batteries are among the most promising next-generation electrochemical energy-storage systems due to their exceptional theoretical specific capacity,inexpensive production cost and environmental friendliness.However,the poor conductivity of S and Li2S,severe lithium polysulfide(LiPS)shuttling and the sluggish redox kinetics of the phase transformation greatly hinder their commercialization.Carbonaceous materials could be potentially useful in Li-S batteries to tackle these problems with their high specific surface area to host LiPSs and sulfur and excellent electrical conductivity to increase electron transfer rate.However,non-polar carbon materials are unable to interact closely with the highly polar polysulfides,resulting in a low sulfur utilization and a serious shuttle effect.Because of their advantages of strong polarity and a large number of adsorption sites,integrating transition metal oxides(TMOs)with carbon-based materials(CMs)increases the chemical adsorption of LiPSs and electrochemical reaction activity for LiPSs.The working principles and main challenges of Li-S batteries are discussed followed by a review of recent research on the ex-situ and in-situ synthesis of TMO/CM composites.The formation of TMO/CMs with the dimensionalities of CMs from 1D to 3D are then reviewed together with ways of changing their structure,including heterostructure design,vacancy engineering and facet manipulation.Finally,the outlook for using TMO/CMs in Li-S batteries is considered.