Defect engineering of porous carbon with high N/S doping for potassium ion storage

• Published in: Applied surface science 2024-06, Vol.657, p.159771, Article 159771
• Main Authors: Qi, Jiqiu, Zhang, Chenchen, Huang, Mengyuan, Zhang, Man, Li, Tianlin, Shi, Meiyu, Wei, Zhengang, Ni, Jianjun, Li, Qian, Sui, Yanwei, Meng, Qingkun, Xiao, Bing, Wei, Fuxiang, Zhu, Lei, Shao, Ruiwen
• Format: Article
• Language: English
• Subjects: DFT calculations; N/S-doped; Porous carbon; Potassium ion battery
• ISSN: 0169-4332
• DOI: 10.1016/j.apsusc.2024.159771

In this chapter, N and S co-doped mesh porous carbon materials (NSC) were prepared using freeze-drying assisted high-temperature carbonization, where sodium polyacrylate was used as the carbon source and sodium thiosulfate (Na2S2O3) and sodium nitrate (NaNO3) is the sulfur and nitrogen sources, respectively. Its unique layered porosity and the ability to dope sulfur atoms up to 5.9 % allows for the introduction of more defect sites and expanded interlayer spatial interactions, achieving impressive electrochemical properties. Enlightened by the properties of N/S double doping and high pore defects, NSC anodes exhibit a high storage of K+ (441.6 mA h/g at 0.05 A/g) and superior rate performance. The density functional theory (DFT) and electrochemical experimental investigation showed the N/S dual doping can successfully modify the electronic structure and improve the capacity of adsorbing K+. Significantly, the assembled dual-carbon PIHC can deliver an impressive energy density of 141.2 Wh kg−1 at a power density of 400 W kg−1 and a satisfactory cycle life when using the NSC-700 porous carbon as the cathode, which can light the “CUMT” pattern, sheding new light on creating improved carbon materials for using in practical applications. [Display omitted] •N and S co-doped mesh carbon materials were prepared for K-ion hybrid capacitors.•High specific surface area and S-rich carbon is designed with a sulfur content of 5.9 %.•The K+ storage mechanism was deeply studied by electrochemical and DFT calculations.•The dual-doped carbon employed in PIHC exhibits an energy density of 141.2 Wh kg-1. The primary research challenge concerning K-ion batteries revolves around ensuring their optimal cycle stability and specific capacity, particularly the inherent sluggish kinetics induced by the relatively large radius of K+. In this study, we report a pore-size controllable synthetic approach employing salt-template precursors. Herein, nitrogen and sulfur co-doped porous carbon materials with rich carbon defect engineering was synthesized through the salt template method, where the doped heteroatoms can both offer a lot of carbon defect content and redox active sites that are helpful for enhancing potassium ion storage kinetics. As a result, the electrode with abundant doping atom content realizes a good capacity and long cycle lifespan (274.8 mA h g−1 after 200 cycles at 0.05 A/g). Inspiringly, PIHCs assembled by N/S co-doped carbon anode exhibit excellent cycling stability