Sulfur‐doped 3D hierarchical porous carbon network toward excellent potassium‐ion storage performance
Dan Wang, Kanghui Tian, Jie Wang, Zhiyuan Wang, Shaohua Luo, Yanguo Liu, Qing Wang, Yahui Zhang, Aimin Hao, Ting‐Feng Yi
Abstract
Abstract Carbonaceous materials are promising anode candidates for potassium‐ion batteries, but currently the unsatisfactory cycling and rate performances due to the sluggish diffusion kinetic and serious structure damage during K + insertion/extraction limit their practical application. Herein, a series of sulfur‐doped porous carbons (SPCs) were prepared via a template‐assisted freeze‐drying followed by the carbonization and sulfuration processes at different temperatures. Among the three as‐synthesized samples, SPC‐600 exhibits the highest specific capacity (407 mAh·g −1 at 0.10 A·g −1 ), the best rate (242 mAh·g −1 at 2.00 A·g −1 ) and cycling performance (286 mAh·g −1 after 800 cycles at 0.50 A·g −1 ). All the SPCs display higher capacities than the undoped carbon materials. The excellent electrochemical performance of SPC can be ascribed to the abundant three‐dimensional porous structure together with S‐doping in the disordered carbon, which is favor of providing adequate reaction active sites as well as fast ion/electron transport paths. The density functional theory (DFT) calculations further demonstrate that the sulfur‐doping can promote K‐ion adsorption and storage. Meanwhile, the kinetic analyses reveal that surface‐induced capacitive mechanism dominates the K‐ion storage process in SPCs, which contributes to ultrafast charge storage. This work provides an effective strategy for fabricating high‐performance potassium‐ion storage electrode materials.