title: Towards Stable Lithium-Sulfur Batteries with a Low Self-Discharge Rate: Ion Diffusion Modulation and Anode Protection.
abstract: The self-discharge of a lithium-sulfur cell decreases the shelf-life of the battery and is one of the bottlenecks that hinders its practical applications. New insights into both the internal chemical reactions in a lithium-sulfur system and effective routes to retard self-discharge for highly stable batteries are crucial for the design of lithium-sulfur cells. Herein, a lithium-sulfur cell with a carbon nanotube/sulfur cathode and lithium-metal anode in lithium bis(trifluoromethanesulfonyl)imide/1,3-dioxolane/dimethyl ether electrolyte was selected as the model system to investigate the self-discharge behavior. Both lithium anode passivation and polysulfide anion diffusion suppression strategies are applied to reduce self-discharge of the lithium-sulfur cell. When the lithium-metal anode is protected by a high density passivation layer induced by LiNO3 , a very low shuttle constant of 0.017 h(-1) is achieved. The diffusion of the polysulfides is retarded by an ion-selective separator, and the shuttle constants decreased. The cell with LiNO3 additive maintained a discharge capacity of 97 % (961 mAh g(-1) ) of the initial capacity after 120 days at open circuit, which was around three times higher than the routine cell (32 % of initial capacity, corresponding to 320 mAh g(-1) ). It is expected that lithium-sulfur batteries with ultralow self-discharge rates may be fabricated through a combination of anode passivation and polysulfide shuttle control, as well as optimization of the lithium-sulfur cell configuration.
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China).
authors.forename: Wen-Tao
authors.initials: WT
authors.lastname: Xu
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China).
authors.forename: Hong-Jie
authors.initials: HJ
authors.lastname: Peng
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China). jqhuang@tsinghua.edu.cn.
authors.forename: Jia-Qi
authors.initials: JQ
authors.lastname: Huang
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China).
authors.forename: Chen-Zi
authors.initials: CZ
authors.lastname: Zhao
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China).
authors.forename: Xin-Bing
authors.initials: XB
authors.lastname: Cheng
authors.affiliation: Beijing Key Laboratory of Green Chemical Reaction, Engineering and Technology, Department of Chemical, Engineering & Department of Chemistry, Tsinghua University, Beijing 100084 (P.R. China). zhang-qiang@mails.tsinghua.edu.cn.
authors.forename: Qiang
authors.initials: Q
authors.lastname: Zhang
mesh_terms: D004058:Diffusion; D011211:Electric Power Supplies; D004566:Electrodes; D007477:Ions; D008094:Lithium / Q000737:chemistry*; D013455:Sulfur / Q000737:chemistry*
chemical_list: D007477:Ions; D013455:Sulfur; D008094:Lithium
keywords: carbon; electrochemistry; lithium; nanotubes; sulfur