Ultralong cycle life enabled by in situ growth of CoMo1−xP/Mo heterostructure for lithium-sulfur batteries

Abstract

Lithium-sulfur batteries (Li-S batteries) are considered as promising new-generation electrochemical energy storage devices due to their extremely high theoretical energy density (2600 Wh kg−1) and theoretical specific capacity (1675 mAh g−1). However, numerous problems such as poor conductivity and the shuttle effect during discharge–charge process limit the practical application of lithium-sulfur batteries. In this work, porous tubular CoMo1−xP/Mo constructed by in situ growth of metal Mo was designed as the sulfur host for lithium-sulfur batteries. The introduction of Mo modulated the electronic structure of CoMoP to improve the conductivity of cathode and facilitate the redox kinetics, as well as the CoMo1−xP/Mo heterostructure was beneficial to inhibit the shuttle effect through the interaction with lithium polysulfides, which improved cycling stability. As a result, CoMo1−xP/Mo/S cathode had a low-capacity decay rate of only 0.029% per cycle after 2000 cycles at 0.5 C. This work provided a new perspective for the further design of high-performance lithium-sulfur battery cathode materials.