Free-standing hybrid porous membranes integrated with transition metal nitride and carbide nanoparticles for high-performance lithium-sulfur batteries

Abstract

Lithium-sulfur batteries are considered as a promising candidate for next-generation energy-storage applications because of its high energy densities. However, the practical utilization of lithium–sulfur batteries is compromised by fast capacity decay, limited sulfur loading and significant polysulfide shuttling. Herein, we designed and prepared a free-standing lithium-sulfur electrode by loading sulfur into a hybrid material (Mo3Ni3N/Mo2C-CBC/S) constructed by growing Mo3Ni3N/Mo2C nanoparticles on carbonized bacterial cellulose film (CBC). High sulfur content up to 70 wt% and high areal sulfur loading of 15.5 mg cm−2 in Mo3Ni3N/Mo2C-CBC/S membrane are achieved. Reversible specific capacities of 1218 and 823 mA h g−1 are delivered for current rates of 0.1 and 1.0 C, respectively. A high capacity over 500 mA h g−1 is retained after 500 cycles at 1.0 C. The superior electrochemical performance of Mo3Ni3N/Mo2C-CBC/S composite is attributed to the unique structure feature and the synergistic effect of the Mo3Ni3N and Mo2C nanoparticles. The Mo3Ni3N/Mo2C component could suppress the dissolution and shuttling of the polysulfides and Mo2C could improve the electronic conductivity of the composite, consequently contributing to the excellent electrochemical performance of the composite.