Abstract
Microsupercapacitors (MSCs) with high energy densities offer viable miniaturized alternatives to bulky electrolytic capacitors if the former can respond at the kilo Hertz (kHz) or higher frequencies. Moreover, MSCs fabricated on a chip can be integrated into thin‐film electronics in a compatible manner, serving the function of ripple filtering units or harvesters of energy from high‐frequency sources. In this work, wafer‐scale fabrication is demonstrated of MXene microsupercapacitors with controlled flake sizes and engineered device designs to achieve excellent frequency filtering performance. Specifically, the devices (100 nm thick electrodes and 10 µm interspace) deliver high volumetric capacitance (30 F cm−3 at 120 Hz), high rate capability (300 V s−1), and a very short relaxation time constant (τ0 = 0.45 ms), surpassing conventional electrolytic capacitors (τ0 = 0.8 ms). As a result, the devices are capable of filtering 120 Hz ripples produced by AC line power at a frequency of 60 Hz. This study opens new avenues for exploring miniaturized MXene MSCs as replacements for bulky electrolytic capacitors.
On‐chip MXene microsupercapacitors are herein designed to achieve excellent alternating current line filtering performance. Frequency response of the MXene microsupercapacitors are highly dependent on flake size, thickness of the electrodes, and spacing between the electrode fingers. Optimized MXene microsupercapacitors are produced at the wafer scale and can successfully filter out pulsed direct current voltage ripples at various frequencies.