A carbon cloth interlayer immobilizes carbon nanotube-supported ternary chalcogen compounds in novel lithium-chalcogenide batteries

Abstract

The development of lithium-chalcogen batteries containing one active species is limited by bottlenecks. Multichalcogen composites that integrate the advantages of each component while avoiding their defects are desired. Herein, carbon nanotubes (CNT) and carboxylated-CNT (CCNT) are adopted as carriers for active substances consisting of S, Se, and Te at a feed ratio of 8:1:1 (SST811). The electrochemical performance of SST811/CCNT is better than that of SST811/CNT because CCNT contains more oxygen-containing functional groups, allowing the active species to be firmly anchored. Cyclic voltammetry (CV) curves, charge-discharge profiles and in-situ Raman results reveal the solid-phase charge-discharge mechanism of SST811/CCNT in ester electrolyte, consisting of a combination of basic reaction steps. To suppress the shedding of active species during long cycling, a carbon cloth (CC) interlayer is introduced between cathode and separator without altering the inherent reaction mechanism of SST811/CCNT. Under the protection of CC interlayer, the capacity of SST811/CCNT remains at 1219.2 mAh g−1 after 300 cycles, which is 1.5 times that without interlayer. The protective effect of CC interlayer is demonstrated by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), X-ray diffraction (XRD), and Raman results. This work inspires the further development of lithium-chalcogenide batteries.