Flexible Electrocatalytic Nanofiber Membrane Reactor for Lithium/Sulfur Conversion Chemistry
Lei Ji, Xia Wang, Yongfeng Jia, Quanli Hu, Limei Duan, Zhibin Geng, Zhiqiang Niu, Weishan Li, Jinghai Liu, Yuegang Zhang, Shouhua Feng
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–Ti 4 O 7 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 LiS and SS bonds, as well as charge transfer along TiS and LiN bonds, which favors bond breakage, bond formation, and the activation of solid‐state S 8 , Li 2 S 2 , and Li 2 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.