Monolithic carbon derived from biomass via zinc-assisted pyrolysis for lithium-sulfur batteries

Abstract

Lithium-sulfur battery is one of the outstanding candidates for next-generation high-energy batteries. Porous carbon is acknowledged as the promising support for sulfur in the cathode. However, a high-areal-loading cost-effective support remains challenging. Herein, a monolith of porous carbon is derived from rice husk via zinc-assisted pyrolysis. It is applied to loading sulfur as a binder-free cathode, where the conductive network improves the conductance and buffers the volume change. The high surface area and rich pores confer the carbon a high sulfur loading of 73 wt.% and 10.3 mg cm-2. Meanwhile, the defective site of the carbon promotes the conversions of polysulfides to suppress the shuttle effect. The cathode thus demonstrates the high capacities of 1337 and 721 mA h g-1 at 0.2 and 3 C, respectively, and it has a long cycling life over 500 cycles at 1 C.