Sustainable Synthesis of N‐Doped Hollow Porous Carbon Spheres via a Spray‐Drying Method for Lithium‐Sulfur Storage with Ultralong Cycle Life

Abstract

AbstractExploring high‐efficiency, long‐term cycling stability, and cost‐effective cathode materials for lithium‐sulfur (Li−S) batteries is hugely desirable and challenging. Herein, we have successfully developed a simple solution‐based spray‐drying method to fabricate nitrogen‐doped hollow porous carbon spheres (N‐HPCS) with biomass lignin as a carbon precursor and cyanuric acid as a N‐dopant and a porogen. The obtained N‐HPCS shows a specific surface area of 446.2 m2 g−1 and high‐level pyrrolic‐N doping of 64.13 %. The N‐HPCS/S cathode has a high initial discharge capacity of 1535.1 and 1104.0 mA h g−1 at 0.1 and 1 C, respectively. In addition, the N‐HPCS/S electrode exhibits outstanding cycle performance after 1000 cycles at 1 C, with a low capacity decay rate of only 0.041 % per cycle, which is superior to most of the recently reported carbon‐based S cathodes. N‐doping causes strong Li2Sx−N chemical adhesion in carbon spheres, effectively suppressing the dissolution and “shuttle effect” of the notorious polysulfide of Li−S batteries, in which pyrrolic‐N plays a leading role in the capture of polysulfides intermediates. This contribution is of great significance to the exploration of many other structure‐property design strategies for ultralong cycle life Li−S energy storage devices.