A helix-shaped polyaniline/sulfur nanowire as novel structure-accommodable lithium-sulfur battery cathode for high-performance electrochemical lithium-storage

摘要

The volume-change and poor conductivity issues of sulfur severely restrict the performance of lithium-sulfur (Li-S) batteries. Herein, we present a novel spring-shaped composite in which the sulfur is coated on helix-structured SiO2@hydrogel nanowires. The helix composite provides a buffer space for the volume-change of sulfur during charge and discharge; and the hydrogel polyaniline (PANI) coating improves the conductivity of the electrode and enables interaction with sulfides which is demonstrated by first-principle modelling. The prepared SiO2@C@PANI/S nanowires exhibit a stable capacity of 940 mAh g(-1) after 120 cycles at a rate of 0.1C, along with a good Coulombic efficiency of 99.8%. The nanowires-based cathode also shows a high rate-performance even after three rounds of repeated measurements. The high performance and the general preparation method would enable the composite to be able to find significant applications for electrochemical energy-storage.