A C-Si-(O) dominated oxygen-vacancy-rich amorphous carbon for enhanced potassium-ion storage

• Published in: Journal of energy storage 2024-06, Vol.89, p.111574, Article 111574
• Main Authors: Guo, Weijia, Chen, Ziyu, Sun, Zongfu, Geng, Chao, Jiang, Jiangmin, Ju, Zhicheng, Feng, Peizhong
• Format: Article
• Language: English
• Subjects: C-Si-(O); Coal tar pitch; Oxygen vacancy; Potassium-ion batteries; Potassium-ion hybrid capacitors
• ISSN: 2352-152X; 2352-1538
• DOI: 10.1016/j.est.2024.111574

Carbon-based materials are regarded as promising anode materials for potassium-ion batteries. However, owing to the limited storage sites and worse diffusion kinetics of K+, leading to inferior potassium ion storage ability. Herein, a creative strategy for molecule-microstructure modification focusing on oxygen vacancy-rich, high-internal spacial scale is proposed, which has employed to prepare porous amorphous SiOx@C composite anode for enhanced potassium-ion storage. In particular, SiOx functions as the inner porous skeleton of composites and contributes to storage activity. The oxygen vacancy with C-Si-(O) accelerates the electron and ion transfer and generates the active sites with enhanced concentration, and the carbon defect enlarges the interlayer spacing, resulting in rapid dynamics and greater storage capacity. As expected, the optimized SiOx@C anode delivers a superior rate performance of 265 mAh g−1 at 2 A g−1. As a practical device application, the assembled potassium-ion hybrid capacitors (SiOx@C//AC) deliver a maximum energy density of 100 Wh kg−1 and a satisfactory cycle stability (5000 cycles). This work sheds light on carbonaceous anode based on oxygen vacancy composite as a promising support to design efficient potassium storage systems. [Display omitted] •Proposing a one-step sintering reduction strategy for molecule-microstructure modification on high-internal spacial scale.•C-Si-(O) of porous amorphous SiOx@C represent the recombination action and vacancy defects exposing abundant active sites.•The porous SiOx functions as a vacancy-provider chemically and structural skeleton.•The SiOx@C anode delivers superior potassium storage performance by assembled potassium-ion batteries and hybrid-ion capacitors.