Dual-heterostructures decorated interweaved carbon nanofibers sulfur host for high performance lithium-sulfur batteries

Abstract Due to the dissolution of Lithium polysulfides (LiPSs), the volume expansion, and poor conductivity, practical applications of Lithium-sulfur batteries (LSBs) are not satisfactory. Herein, dual-heterostructure decorated interweaved carbon nanofibers are proposed as sulfur hosts to significantly improve the energy storage behavior of LSBs. The unique structure of the interweaved carbon nanofibers and heterostructures provides more transmission channels for electrons and ions while also accelerating the process. Moreover, the heterostructures induce chemical anchoring and catalytic conversion of LiPSs. As a result, the cathode in the coin cell delivers an initial capacity of 777.9 mAh g−1 at 1C and high retention of 68.59% after 600 cycles. In the pouch cell, the cathode delivers a discharge capacity of 907.8 mAh g−1 and a reversible charging capacity of 913.1 mAh g−1 for the first cycle with an ultra-high sulfur loading up to 9.136 mg cm−2. Beyond that, density functional theory calculations, X-ray photoelectron spectroscopy, symmetric cell, and Li2S nucleation tests were adopted to verify the adsorption and catalytic conversion mechanisms of the cathode. This excellent interweaved dual-heterostructure sulfur host provides a novel structural design strategy for efficient chemical adsorption and catalytic conversion of LiPSs, as well as more opportunities for the commercial application of LSBs.