Flexible Electrocatalytic Nanofiber Membrane Reactor for Lithium/Sulfur Conversion Chemistry. (13th May 2020)

• Record Type: Journal Article
• Authors: Ji, Lei; Wang, Xia; Jia, Yongfeng; Hu, Quanli; Duan, Limei; Geng, Zhibin; Niu, Zhiqiang; Li, Weishan; Liu, Jinghai; Zhang, Yuegang; Feng, Shouhua
• Is Part Of: Advanced functional materials. Volume 30:Number 28(2020)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2020-05-13
• Subjects: chemisorption and electrocatalysis -- conversion chemistry -- Li/S batteries -- membrane reactors -- TiN–Ti4O7 core–shell nanofibers; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201910533
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Severe lithium polysulfide (LiPS) shuttle effects and sluggish electrochemical conversion kinetics constitute bottlenecks in developing fast‐rechargeable, high‐energy, and high‐power Li/S batteries. Here, a flexible and conductive TiN–Ti4 O7 core‐shell nanofiber (TiNOC) membrane reactor is designed to electrocatalytically mediate Li/S conversion chemistry. The Ti, N, and O atoms in the nanofiber function as electrocatalysts and chemical confinement active sites to initiate long‐chain LiPS conversion and phase change, as well as to suppress soluble LiPS shuttling. With a sulfur cathode‐membrane reactor module configuration, Li/S cells possess a high sulfur utilization of 91.20%, good rate capability of 869.10 mA h g −1, and high capacity retention of 92.49%, with a coulomb efficiency of 99.57% after 200 cycles at 5 C. Density functional theory (DFT) calculations revealed that the optimized chemisorption configurations facilitate the elongation of LiS and SS bonds, as well as charge transfer along TiS and LiN bonds, which favors bond breakage, bond formation, and the activation of solid‐state S8, Li2 S2, and Li2 S. Layer‐by‐layer module stacking provides Li/S batteries with a high areal sulfur loading of 12.00 mg cm −2 to deliver a high areal capacity of 14.40 mA h cm −2 at 2.26 mA. Two batteries in series can power real‐world applications such as light emitting diode (LED) bulbs with a high energy output of 69.00 mW h. Abstract : A flexible TiN–Ti4 O7 core–shell nanofiber membrane reactor is designed to electrocatalytically mediate Li/S conversion chemistry. Atomic Ti, N, and O active sites confine soluble polysulfides on the nanofiber to favor SS and LiS bond breakage, bond formation, and activation. The layer‐by‐layer module stacking technique results in high areal sulfur loading and high areal capacity Li/S batteries for real‐world applications.