CNTs@S composite as cathode for all-solid-state lithium-sulfur batteries with ultralong cycle life

Abstract The main challenges in development of traditional liquid lithium-sulfur batteries are the shuttle effect at the cathode caused by the polysulfide and the safety concern at the Li metal anode arose from the dendrite formation. All-solid-state lithium-sulfur batteries have been proposed to solve the shuttle effect and prevent short circuits. However, solid-solid contacts between the electrodes and the electrolyte increase the interface resistance and stress/strain, which could result in the limited electrochemical performances. In this work, the cathode of all-solid-state lithium-sulfur batteries is prepared by depositing sulfur on the surface of the carbon nanotubes (CNTs@S) and further mixing with Li 10 GeP 2 S 12 electrolyte and acetylene black agents. At 60  °C, CNTs@S electrode exhibits superior electrochemical performance, delivering the reversible discharge capacities of 1193.3, 959.5, 813.1, 569.6 and 395.5 mAh g −1 at the rate of 0.1, 0.5, 1, 2 and 5 C, respectively. Moreover, the CNTs@S is able to demonstrate superior high-rate capability of 660.3 mAh g −1 and cycling stability of 400 cycles at a high rate of 1.0 C. Such uniform distribution of the CNTs, S and Li 10 GeP 2 S 12 electrolyte increase the electronic and ionic conductivity between the cathode and the electrolyte hence improves the rate performance and capacity retention.