氧化还原媒介体分子调控锂-硫电池硫正极性能研究进展  

Research progress in sulfur-based cathode modulated by redox mediators in lithium-sulfur batteries

作　　者：颜雪冬 王树增 张树国 杜晨树 罗金宝 YAN Xue-dong;WANG Shu-zeng;ZHANG Shu-guo;DU Chen-shu;LUO Jin-bao(College of Chemical Engineering,Ningbo Polytechnic,Institute of Energy Storage and Conversion Technology,Ningbo 315800,China;Ningbo Veken Battery Co.,Ltd,Ningbo 315800,China;Ningbo Jintian Copper(Group)Co.,Ltd,Ningbo 315800,China)

机构地区：[1]宁波职业技术学院化学工程学院,能量存储与转换技术研究所,浙江宁波315800 [2]宁波维科电池有限公司,浙江宁波315800 [3]宁波金田铜业(集团)股份有限公司,浙江宁波315800

出　　处：《分子科学学报》2023年第1期11-19,共9页Journal of Molecular Science

基　　金：浙江省公益技术研究计划资助项目(LGG19E020001);宁波职业技术学院人才引进项目(RC201802);浙江省访问工程师项目(FG2020048);宁波市“科技创新2025”重大专项资助项目(2018B10043)。

摘　　要：锂-硫(Li-S)电池具有较高的理论比容量(约1 675 mAh·g^(-1))和能量密度(约2 600 Wh·g^(-1)),被认为是继锂离子电池之后最有前途的下一代高能量密度电池.Li-S电池在实现产业化之前需要克服硫正极诸多技术瓶颈,主要有硫的导电性差、多硫化物的穿梭效应与硫电极体积膨胀等.本文着重梳理了氧化还原媒介体分子在硫正极改性研究上的进展,并对硫正极的未来发展趋势进行了展望.The lithium sulfur(Li-S) battery with high theoretical specific capacity(about 1 675 mAh·g^(-1)) and energy density(about 2 600 Wh·g^(-1)) is considered to be the most promising next-generation high-energy battery after lithium-ion battery. However, before the industrialization of Li-S battery, many technical bottleneck problems of the sulfur cathode materials need to be overcome, such as(1) poor conductivity of sulfur and Li2S: both sulfur and Li2S are insulators with very low electronic conductivity, which results poor rate capability of Li-S battery;(2) shuttle effect of polysulfide: the dissolution of high order polysulfides(Li2Sx, 4≤x≤8) will cause the low Coulomb efficiency and poor cycling of Li-S battery;and(3) volume expansion of sulfur electrode: the volume expands dramatically by 80% during sulfur reduced to Li2S results in significant stress in the electrode and stripping off. Among the modified strategies of sulfur electrode, the redox mediators(RMs) strategy play a pivotal role to enhance the electrochemical performances of Li-S battery. Generally, RMs, a series of molecules, polymers, ions, or compounds, is soluble in electrolyte and can be electrochemical oxidized and reduced reversibly upon cycling. Assisted by the RMs, the electrochemical reactions can be accelerated through overcome the excessive activation energy or enhance electron transportation processes. Moreover, RMs can decouple the electrochemical reaction by preserving electrons or holes from a half-reaction. To accomplish this purpose, the inherent properties of optimal RMs should contain high reversibility, good solubility, faster kinetics, and negligible parasitic reactions. Moreover, the redox potential of RMs should be chosen carefully, which is slightly higher than the reduction potential of sulfur to Li2S reaction or lower than the oxidation potential of Li2S to sulfur reaction. In sulfur-based electrochemical reaction, the RMs only serves as intermediate electron carriers without changing the intrinsic products. Depending

关 键 词：锂-硫电池 氧化还原介体分子 硫正极 多硫化物 穿梭效应 

分 类 号：O646[理学—物理化学]