High-frequency supercapacitors with phosphorus-doped Ketjen black

• Published in: Journal of energy chemistry 2023-07, Vol.82, p.464-474
• Main Authors: Jin, Qing, Khandelwal, Mahima, Kim, Woong
• Format: Article
• Language: English
• Subjects: AC line filtering; DFT calculation; Frequency response; Phosphorus doping; Supercapacitor; Wettability
• ISSN: 2095-4956
• DOI: 10.1016/j.jechem.2023.03.041

P-doping functional groups on KB increase supercapacitor capacitance by improving electrolyte ion adsorption and wettability while maintaining high-frequency properties. [Display omitted] Compact supercapacitors (SCs) have attracted attention for their great potential to replace bulky aluminum electrolytic capacitors (AECs) in alternating current (AC) line filtering applications. Herein, the fabrication of a high-frequency SC is reported using Ketjen black (KB) nanoparticles doped with phosphorus (P) to achieve a high areal capacitance of up to 2.26 mF cm−2 along with a high-rate capability, with a phase angle of –80.2° at 120 Hz. The high performance of the phosphorus-doped KB (designated PKB) SC with a 6 M KOH aqueous electrolyte is associated with its increased surface wettability and additional capacitive sites provided by the P-doping. Density functional theory (DFT) calculations further indicate that the P-doping enhances the interactions between the electrolyte ions and the carbon surface, thus leading to an improved electrochemical performance. These results suggest that the P-doped carbon-based SC could be highly favored in replacing conventional AECs in various high-frequency electronic devices.