锂硫电池中的催化作用

Catalysis in Lithium-Sulfur Batteries

锂硫电池理论能量密度高达2600 Wh·kg^(-1),单质硫的理论容量可达1675 mAh·g^(-1),远高于商业化的锂离子电池正极材料,但多硫化锂的“穿梭效应”等问题对其性能影响严重。目前研究主要采用基于“阻挡”的物理限制和化学吸附策略将多硫化锂限制在正极侧。而基于“疏导”的催化转化策略则通过加快氧化还原反应动力学,在抑制“穿梭效应”的同时实现降低过电位、诱导Li2S均匀沉积等功能。本文综述了锂硫电池中的催化作用,基于是否产生氧化还原中间体将其分为吸附-转化机制和氧化还原介导机制两类;并介绍了相关的材料及常用的表征技术和研究方法。

Lithium-sulfur batteries have a theoretical energy density of up to 2600 Wh·kg-1,and the theoretical capacity of sulfur can reach 1675 mAh·g-1,which is much higher than that of commercial cathode materials of lithium-ion batteries.However,problems such as the"shuttle-effect"of polysulfides have a serious impact on the performance.Current researches mainly use physical limitation and chemisorption to limit polysulfides to the cathode region based on the"blocking"strategies.Inspired by the concept of“dredging”,the catalytic-conversion strategy can realize functions such as reducing overpotential and inducing uniform deposition of Li 2S while suppressing the"shuttle-effect"by speeding up the oxidation-reduction reaction kinetics.Herein,we review the progress of catalysis in lithium-sulfur batteries and divide them into adsorption-conversion mechanisms and redox-mediated mechanisms based on whether redox intermediates are produced.Related materials and characterization techniques and research methods commonly used are also introduced.