Inverse Fabrication of Li2S‐Nanocrystals@Doped‐Carbon Loaded on Woven Carbon Fibers to Spatial Structure Cathodes for High‐Stable Lithium–Sulfur Batteries

Abstract Lithium sulfide (Li 2 S) is an attractive cathode material for lithium–sulfur batteries due to its matching with the lithium‐metal‐free anode, but limited by its preparation and processing difficulty, low electronic conductivity, and high dissolution of polysulfide intermediates. Herein, a novel, low‐cost, and scalable method (termed as inverse fabrication route) is proposed to directly prepare Li 2 S‐based electrodes. This methodology uniformly anchors in situ generated Li 2 S nanocrystals with a controllable size of 5–10 nm on the woven carbon fibers (WCF) substrate to fabricate a spatial conductive network structure, which provides continuous high‐speed pathways for electron/ion transport. Furthermore, Li 2 S nanocrystals are encapsulated into a nitrogen/fluorine (N/F) codoped carbon framework to directly fabricate a spatial structure of Li 2 S‐nanocrystals @ doped‐carbon/WCF (Li 2 S @ DC/WCF) composite cathode. N/F codoped carbon yields certain catalytic effects on the electrochemical redox reaction for lithium–sulfur batteries, and N‐containing groups in carbon lead to a strong chemical interaction with Li 2 S/lithium polysulfides, thus improving the electrochemical reaction kinetics and suppressing the polysulfide shuttle. Hence, the as‐prepared Li 2 S @ DC/WCF composite cathode exhibits a high discharge capacity of 913 mA h g −1 at 0.2C, and the discharge capacity remains at 98% even after 200 cycles at 1C, corresponding to an average capacity decay of 0.01% cycle −1 .