Ultrafast supercapacitors based on boron-doped Ketjen black and aqueous electrolytes

Compact supercapacitors (SCs) are considered as a promising alternative to bulky aluminum electrolytic capacitors (AECs) for alternating current (AC) line filtering applications. Although the recently-developed SCs based on heteroatom-doped and/or macro/mesoporous carbon materials exhibit sufficiently fast response speeds for such applications, improvements in their performance characteristics (e.g., capacitance) would be highly desirable. In particular, the SCs with heteroatom-doped carbons have thus far exhibited limited capacitances at high frequencies (< 0.5 mF cm(-2) at 120 Hz). In the present work, SCs with boron (B)-doped mesoporous Ketjen black (KB) and a 6 M KOH electrolyte are shown to exhibit a high areal capacitance of 1.67 mF cm(-2), along with a high frequency response (negative phase angle, -Phi = 81.5 degrees) at 120 Hz. The excellent performance of the B-doped KB SCs can be attributed to the improved wettability and electrical conductivity, and to the increased number of capacitive sites due to the B-doping. This demonstration may greatly contribute to the development of high performance SCs suitable for high frequency applications.

Automated summary

The study demonstrates that SCs with boron-doped mesoporous Ketjen black and a 6 M KOH electrolyte exhibit high areal capacitance and high frequency response. This is attributed to the improved wettability and electrical conductivity, as well as the increased number of capacitive sites due to boron-doping.