Non-Carbon-Dominated Catalyst Architecture Enables Double-High-Energy-Density Lithium-Sulfur Batteries

The commonly used catalyst on carbon architecture as a sulfur host is difficult to jointly achieve high gravimetric and volumetric energy densities for lithium-sulfur (Li-S) batteries due to the contradiction between low tap density/poor catalytic activity of carbon and the easy agglomeration of metal-based compounds without carbon. Here, a non-carbon-dominated catalytic architecture using macroporous nickel/cobalt phosphide (NiCoP) is reported as the sulfur host for Li-S batteries. The macroporous framework, which accommodates a large amount of sulfur, can accelerate the electrochemical reaction kinetics by accelerated e- transport, Li+ diffusion, and superior adsorption and catalytic activity of inherent Ni2P/CoP heterostructures. The high tap density (0.45 g cm(-3)) and mechanically hard features contribute to the excellent structural and physicochemical stability of the NiCoP@S electrode after the pressing and rolling process. These features enable the Li-S coin cell to exhibit excellent electrochemical performance under conditions of high sulfur loading (10.2 mg cm(-2)) and lean electrolyte (electrolyte/sulfur of 2 mu L mg(-1)). Inspiringly, the assembled pouch cell can simultaneously deliver a gravimetric energy density of 345.2 Wh kg(-1) and an impressive volumetric energy density of 952.7 Wh L-1 based on the entire device configuration.

Automated summary

This study reports a new non-carbon-dominated catalytic system using macroporous nickel/cobalt phosphide (NiCoP) as the sulfur host for lithium-sulfur (Li-S) batteries. The catalytic system exhibits high tap density and mechanical hardness, improving the electrochemical reaction kinetics and showing excellent electrochemical performance under high sulfur loading and lean electrolyte conditions.