FeSb@N-doped carbon quantum dots anchored in 3D porous N-doped carbon with pseudocapacitance effect enabling fast and ultrastable potassium storage
Zhihui Li, Qingmeng Gan, Yifan Zhang, Jing Hu, Peng Liu, Changhong Xu, Xibing Wu, Yilin Ge, Feng Wang, Qingrong Yao, Zhouguang Lu, Jianqiu Deng
Abstract
Potassium-ion batteries (PIBs) are promising next-generation energy storage candidates due to abundant resources and low cost. Sb-based materials with high theoretical capacity (660 mAh·g−1) and low working potential are considered as promising anode for PIBs. The remaining challenge is poor stability and slow kinetics. In this work, FeSb@N-doped carbon quantum dots anchored in three-dimensional (3D) porous N-doped carbon (FeSb@C/N⊂3DC/N), a Sb-based material with a particular structure, is designed and constructed by a green salt-template method. As an anode for PIBs, it exhibits extraordinarily high-rate and long-cycle stability (a capacity of 245 mAh·g−1 at 3,080 mA·g−1 after 1,000 cycles). The pseudocapacitance contribution (83%) is demonstrated as the origin of high-rate performance of the FeSb@C/N⊂3DC/N electrode. Furthermore, the potassium storage mechanism in the electrode is systematically investigated through ex-situ characterization techniques including ex-situ transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). Overall, this study could provide a useful guidance for future design of high-performance electrode materials for PIBs.