摘要
Lithium-sulfur(Li-S)batteries face significant challenges due to the environmental sensitivity,dendrite growth and polysulfide-induced side reactions of lithium metal anodes(LMAs),which compromise their safety and cycle life.To address these issues,we develop a composite protective layer comprising layer-by-layer assembled graphene oxide(GO)films coated with 1H,1H,2H,2H-perfluorodecyl trichlorosilane(FDTS).The lithium-reduced GO framework establishes uniform ion-conducting channels that homogenize Li-ion flux,enabling uniform deposition and suppressing dendrite formation.At the same time,the hydrophobic organic coating serves as a robust barrier against water,air and lithium polysulfides(LiPSs),enabling the environmental and electrochemical stability of LMAs.As a result,the protected LMAs maintain exceptional stability upon direct contact with water and exposure in humid air(relative humidity 35%).When integrated into Li-S batteries with high sulfur loadings(4.5 mg cm^(-2)),the protected LMAs enable a capacity retention of 61.1%over 300 cycles,showing improved cycling performance.This work provides a scalable approach to stabilizing LMAs for practical Li-S batteries.
锂金属负极的高活泼性、枝晶生长及与多硫化物间的副反应等问题严重降低了锂硫电池的安全性和循环寿命.对此,我们设计了一种复合保护层,由层状氧化石墨烯和1H,1H,2H,2H-全氟癸基三氯硅烷(FDTS)包覆层构成.具有层状结构的氧化石墨烯在锂表面被还原,作为锂离子整流通道实现均匀的离子传输,抑制枝晶生长.同时,疏水FDTS层可有效阻隔水、空气和多硫化锂的腐蚀,提高锂金属负极的环境和电化学稳定性.实验结果表明,受保护的锂金属负极在接触水和暴露于湿度为35%的空气时仍能保持出色的稳定性.将受保护的锂金属负极应用到高负载(4.5 mg cm^(-2))锂硫电池中,电池300次循环后的容量保持率达61.1%,循环稳定性显著提升.该工作为锂硫电池中锂金属负极的规模化应用提供了借鉴.
基金
supported by the National Natural Science Foundation of China(52302299,U23B2077)
the National Key R&D Program of China(2021YFF0500600)
the Guangdong Basic and Applied Basic Research Foundation(2023B1515120047)
the Shenzhen Science and Technology Program(JCYJ20220818101008018)
the Shenzhen Outstanding Talents Training Fund
the Fundamental Research Program of Shanxi Province(202203021212213)。
