超薄MoS2纳米片改性隔膜用于锂硫电池的研究  

Research on ultrathin MoS2 nanosheets modified separator for lithium-sulfur batteries

作　　者：李娇娇 王风彦[1,2] 马志鹏[1,2] 邵光杰[1,2,3] LI Jiaojiao;WANG Fengyan;MA Zhipeng;SHAO Guangjie(Hebei Key Laboratory of Applied Chemistry,Yanshan University,Qinhuangdao,Hebei 066004,China;School of Environmental and Chemical Engineering,Yanshan University,Qinhuangdao,Hebei 066004,China;State Key Laboratory of Metastable Materials Science and Technology,Yanshan University,Qinhuangdao,Hebei 066004,China)

机构地区：[1]燕山大学河北省应用化学重点实验室,河北秦皇岛066004 [2]燕山大学环境与化学工程学院,河北秦皇岛066004 [3]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《燕山大学学报》2019年第6期518-524,共7页Journal of Yanshan University

基　　金：国家自然科学基金资助项目(51674221,51704261);河北省自然科学基金资助项目(B2018203330)

摘　　要：与锂离子电池相比,锂硫电池具有较高的理论能量密度。然而,硫具有较差的电子导电性,以及充放电过程中体积膨胀和放电产物多硫化锂的“穿梭效应”,这将导致实际应用中电池的循环寿命很差。在本文中,利用溶剂插层剥离法将MoS 2体相材料剥离成超薄的纳米片。后续通过简单的真空抽滤法将高导电性的碳纳米管和超薄MoS 2纳米片的乙醇分散液依次修饰在商用聚丙烯隔膜上。电化学测试结果表明,使用CNT+MoS 2/PP隔膜的锂硫电池在1C下显示出了924.4 mAh/g的高容量,200次循环后保持573.7 mAh/g的高可逆容量,容量保持率为80.3%,每圈容量衰减率仅为0.098%,明显优于使用聚丙烯隔膜的电化学性能。这主要是由于超薄的MoS 2纳米片能够有效地吸附长链多硫化物(Li 2S x,4≤x≤8),同时高导电性的碳纳米管能够高效地将其还原成Li 2S 2/Li 2S,从而抑制了多硫化物的“穿梭效应”。Lithium-sulfur batteries have higher theoretical energy densities than lithium-ion batteries.However,sulfur has poor electronic conductivity,as well as lager volume expansion during charge and discharge and"shuttle effect"of the discharge product lithium polysulfide,which results in miserable cycle performance of lithium-sulfur battery in practical applications.In this paper,the MoS 2 bulk phase material was peeled off into ultrathin nanosheets by solvent intercalation stripping.Subsequently,the highly conductive carbon nanotubes and the ultrathin MoS 2 nanosheet of ethanol dispersion were respectively modified on a commercial polypropylene separator by a simple vacuum filtration method.Electrochemical test results show that lithium-sulfur batteries with CNT+MoS 2/PP separator display high capacity of 924.4 mAh/g at 1 C,excellent reversible capacity of 573.7 mAh/g and capacity retention rate of 80.3%after 200 cycles,and the capacity decay rate is only 0.098%,significantly better than that of lithium-sulfur battery with polypropylene separator.This can mainly be accounted for based on the fact the ultra-thin MoS 2 nanosheets can effectively adsorb long-chain polysulfides(Li 2S x,4≤x≤8),while the highly conductive carbon nanotubes can efficiently reduce them to Li 2S 2/Li 2S,thus inhibiting the"shuttle effect"of the long-chain lithium polysulfide.

关 键 词：锂硫电池 隔膜改性 超薄MoS2纳米片 穿梭效应 

分 类 号：TN9152[电子电信—通信与信息系统]