High Sulfur-doped hollow carbon sphere with multicavity for high-performance Potassium-ion hybrid capacitors

Lantao Liu; Yiming Li; Shuaize Wang; Yaping Lu; Jiapeng Zhang; Dengke Wang; Yinghui Ding; Daping Qiu; Jin Niu; Yingchun Yu; Xiaohong Chen; Huaihe Song

doi:10.1016/j.jcis.2022.08.007

High Sulfur-doped hollow carbon sphere with multicavity for high-performance Potassium-ion hybrid capacitors

J Colloid Interface Sci. 2022 Dec 15;628(Pt A):975-983. doi: 10.1016/j.jcis.2022.08.007. Epub 2022 Aug 3.

Authors

Affiliations

¹ State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, PR China.
² State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: yuyc@mail.buct.edu.cn.
³ State Key Laboratory of Chemical Resource Engineering, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, PR China. Electronic address: chenxh@mail.buct.edu.cn.

PMID: 35964444
DOI: 10.1016/j.jcis.2022.08.007

Abstract

S doping is an effective strategy to improve the potassium-ion storage performance of carbon-based materials. However, due to the large atomic radius of S and poor thermal stability, it is challenging to synthesize carbon materials with high sulfur content by solid-phase transformation. In this work, we designed a multi-cavity structure that can confine the molten S during heat treatment and make it fully react, then achieving high S doping (7.6 at. %). As we known, S doping can also effectively increase the active sites of carbon materials to obtain higher capacity. In addition, through different ex/in-situ characterizations and DFT calculations, we confirmed that the S atoms can effectively expand the interlayer spacing of carbon, which facilitates the intercalation/deintercalation reaction of K⁺, thereby significantly improving the rate performance. Therefore, benefiting from the effect of S-doping, the sample exhibits high reversible specific capacity (401.0 mAh g^-1 at 0.1 A/g) and rate performance (167.2 mAh g^-1 at 5 A/g). The as-assembled K⁺ hybrid capacitor delivers both high energy density and power density (138.5 W h kg^-1 and 7692.5 W kg^-1, respectively). This work provides a new approach to design S content carbon-based materials for high performance K⁺ storage.

Keywords: Energy storage mechanism; K-ion hybrid capacitors; Multi-cavity carbon microspheres; S-doped.