A N/S/O-tridoped hard carbon network anode from mercaptan/polyurethane-acrylate resin for potassium-ion batteries

Hard carbon is a promising anode material for potassium-ion batteries (KIBs) due to its disordered and nonexpendable framework. However, the potassium storage performance in hard carbon still needs to be further improved. In this paper, functional nitrogen, sulfur and oxygen tri-doped hard carbon network (NSO-HCN), prepared through a carbonization-etching strategy using the precursor of mercaptan/polyurethane-acrylate (MPUA) resin, was promoted as the anode for KIBs. The obtained amorphous NSO-HCN possessed a porous 3D interconnected carbon network structure with an expanded interlayer distance (0.391 nm) and a large Brunauer–Emmett–Teller (BET) specific area (500.4 m2/g). These features allowed the NSO-HCN to deliver a high potassiation capacity of 209.6 mAh/g at 50 mA/g over 100 cycles and a favorable cycling stability by preserving potassiation capacities of 184.2, 146.8, and 136.0 mAh/g over 200 cycles at 100, 200 and 500 mA/g, respectively.