Co9S8-C-Li2S composite synthesized via synchronous carbothermal reduction process as cathode material for high-performance Li-ion-S batteries

Abstract An economic and convenient synchronous carbothermal reduction is introduced to prepare Co9S8-C-Li2S composite as cathode material for Li-ion-S battery. The synthesized Co9S8-C-Li2S composite greatly reduces the cost of Li2S cathode. Furthermore, small particles of Li2S and Co9S8 are formed in-situ at the same time and distribute uniformly in carbon matrix. Meanwhile, the formation of the polar material Co9S8 effectively inhibits the “shuttle effect”, regulates the electrochemical reaction between Li2S and S, and significantly reduces the activation voltage of Li2S. As a result, Li-ion-S battery with Co9S8-C-Li2S cathode exhibits a lower active voltage of 2.5 V and a higher initial charge specific capacity of 1166 mA h g−1.