Spatially synthesized fluorine-modified graphene improves double times higher capacitance than theoretical capacitance of graphene in alkaline medium

Limin Wang; Zhenxiang Chen; Yongchun Liu; Rajkumar Devasenathipathy; Dan Li; Dujuan Huang; Qiulan Huang; Liujie Lu; Ziyi Huang; Du-Hong Chen; Youjun Fan; Wei Chen

doi:10.1016/j.jcis.2025.137418

Spatially synthesized fluorine-modified graphene improves double times higher capacitance than theoretical capacitance of graphene in alkaline medium

J Colloid Interface Sci. 2025 Aug:691:137418. doi: 10.1016/j.jcis.2025.137418. Epub 2025 Mar 22.

Authors

Affiliations

¹ Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China.
² Center of Molecular Medicine and Dianostics (COMManD), Saveetha Dental College and Hospitals, SIMTS, Saveetha University, Chennai 600077, Tamil Nadu, India.
³ Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China. Electronic address: dhchen@gxnu.edu.cn.
⁴ Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China. Electronic address: youjunfan@mailbox.gxnu.edu.cn.
⁵ Guangxi Key Laboratory of Low Carbon Energy Materials, School of Chemistry and Pharmaceutical Sciences, Guangxi Normal University, Guilin 541004, China. Electronic address: weichen@mailbox.gxnu.edu.cn.

PMID: 40147371
DOI: 10.1016/j.jcis.2025.137418

Abstract

The practically low energy density limits the large-scale application of graphene in supercapacitors. Here, we propose a space-confined method for the preparation of fluorine-modified graphene (FG) by using fluorine-containing groups (PF₆^- or BF₄^-) as co-intercalated ions and reactants. The semi-ionic C-F bonds in FG contribute a brilliant capacitive performance in both acidic and alkaline electrolytes. Particularly, in alkaline medium, the FG electrode exhibited an ultrahigh specific capacitance (1210 F g^-1), surpassing 2 orders of the theoretical capacitance value of graphene. Meanwhile, the FG-assembled symmetrical supercapacitor device (FG-SSD) possesses ultrahigh energy density (418.7 Wh kg^-1) and power density (2 kW kg^-1) in acidic medium, highlighting the practical application of supercapacitors. Theoretical calculations revealed an increased electrochemical double layer capacitance and amplified the electrochemical window of FG-SSD. This work demonstrates a spatially confined method for the preparation of functional graphene and its spectacular potential for supercapacitor-related electronics.

Keywords: Fluorine-modified graphene; Spatial confinement; Supercapacitor; Synthesis mechanism; Theoretical calculation.