Sulfur-Doped Flowerlike Porous Carbon Derived from Metal–Organic Frameworks as a High-Performance Potassium-Ion Battery Anode

Amorphous carbon shows great potential in K+ storage due to its low cost and adjustable interlayer distance. However, the sluggish diffusion kinetics for K+ in carbon lattice and unsatisfied capacity hinder the further application of carbon materials such as a PIB anode. Herein, we reported the MIL-88A-derived sulfur-doped porous carbon for a potassium-ion battery (PIB) anode using a facile multistep strategy. Benefiting from the unique structure of the MIL-88A precursor, the obtained carbon material with a three-dimensional (3D) open framework has a large specific area to shorten the K+ transport path. At the same time, S dopants introduce more defects and then promote K+ storage capability. Therefore, the sulfur-doped porous carbon anode shows a high reversible capacity over 358 mA h g–1 and extraordinary rate performance (192.6 mA h g–1 at 2.0 A g–1). The first-principles calculations confirm that the functional S doping in the carbon matrix promotes K adsorption.