Ultrahigh-rate and high-frequency MXene micro-supercapacitors for kHz AC line-filtering

Abstract Harnessing energy from the environment promotes the rapid development of micro-power generators and relevant power management modules of alternating current (AC) line-filtering to obtain a stabilized direct current (DC) output for storage and use. Micro-supercapacitors (MSCs) with miniaturized volume and high-frequency response are regarded as a critical component in filtering circuits for microscale power conversion. Here, we reported the fabrication of the wafer-sized planar MSCs (M-MSCs) based on 2D Ti3C2Tx MXene using a photolithography technique. The M-MSCs exhibited an areal capacitance of 153 μF cm−2 and a frequency characteristic (f0) of 5.6 kHz in aqueous electrolyte. Moreover, by employing suitable ionic liquid as electrolyte, the voltage window was expanded to 2 V and the f0 could be pushed to 6.6 kHz relying on the electrical double-layer mechanism and lower adsorption energy while maintaining quasi-rectangular cyclic voltammogram curves at 5000 V s−1. Furthermore, the integrated MSCs pack was constructed and exhibited excellent rectifying ability by filtering various high-frequency 5000 Hz AC signals with different waveforms into stable DC outputs. Such ultrahigh-rate and high-voltage M-MSCs module for kHz AC line-filtering would be potentially integrated with customizable electronics to realize on-chip rectifiers in high-density integrated circuit.