Ternary confined-functional sulfur composite with a host–sulfur–container architecture for lithium/sulfur batteries

Abstract

In this work, a ternary confined-functional sulfur composite with a Host–Sulfur–Container structure is designed and synthesized for high performance lithium sulfur batteries. The host in this unique architecture is porous carbon, which contains interconnected macropore tunnels and meso/micropores on the macropore tunnel walls. These hierarchical pores exhibit a synergistic effect to adsorb sulfur in their spaces and provide more nucleation sites to direct the uniform coating of sulfur. Moreover, the interconnected porous structure can facilitate electron transfer and also ensure high sulfur utilization. Furthermore, the poly(3,4-ethylenedioxythiophene) layer container improves the conductivity of the electrode, prevents the diffusion of dissolved polysulfide, and prevents volume expansion during the charge–discharge processes. As a result, the electrode with the poly(3,4-ethylenedioxythiophene)/sulfur/porous carbon composite and Host–Sulfur–Container architecture maintains a reversible capacity of 831.9 mA h g⁻¹ after 200 cycles at a current density of 0.5 C and presents long-term cycling stability with 0.088% capacity decay per cycle over 500 cycles at 1 C. This indicates that the prepared Host–Sulfur–Container composite is a promising cathode material for lithium–sulfur batteries, and its hierarchical tunnel pore carbon host with meso/micropores inside shows great potential in the energy storage field.