Mesoporous TiN microspheres as an efficient polysulfide barrier for lithium–sulfur batteries

Abstract

Although lithium–sulfur batteries are expected to be the promising next generation of energy storage systems, the shuttle effect of polysulfides severely hampers their practical application. In this study, we introduce mesoporous titanium nitride microspheres to decorate the commercial separator and effectively suppress the shuttle effect. Specifically, titanium nitride improves the utilization of sulfur as an upper current collector through its strong chemical adsorption for polysulfides and high conductivity. In addition, its mesoporous spherical structure also forms a favorable physical barrier to block the diffusion of polysulfides. With this titanium nitride modified separator, the cell exhibits an excellent capacity retention ratio of 76% after 200 cycles at 0.5C. A relatively high capacity of 672 mA h g⁻¹ is obtained even at a high current density of 3C. These results suggest that the design of separators modified with transition metal nitride-based materials is a promising approach for developing high performance lithium–sulfur batteries.