Polar Co3Se4 nitrogen-doped porous carbon derived from ZIF-67 for use as a sulfur substrates in high-performance lithium-sulfur batteries

Lithium-sulfur batteries can have several times the energy density of conventional lithium-ion batteries and are a likely replacement for such batteries in high-daensity storage systems. Nevertheless, slow reaction kinetics, the shuttle effect of polysulfides and a low Coulomb efficiency hinder the commercialization of lithium-sulfur batteries. In this work, a polar Co3Se4 nitrogen-doped porous carbon (Co3Se4-N-C) framework material was synthesized from ZIF-67 and used as a sulfur substrate for Li-S batteries to retard the shuttle effect of LiPSs and improve the cycling stability. Based on experiments and theoretical calculations, it is proven that Co3Se4-N-C is an effective electrode material to promote polysulfide conversion. The specific capacity of discharge at 0.1 C reaches 1370.9 mAh g−1, with a decay rate of 0.057 % per cycle after 500 cycles at 1 C.