High-voltage (> 3 V) energy storage device based on sputter-grown TiCrN microelectrodes towards miniaturized applications

Abstract

In this work, we report sputter-grown micro-patterns of titanium chromium-based bimetallic nitride (TiCrN) over Si/SiO2 substrate. The highly stable TiCrN-micro pattern is tested electrochemically and used to construct an efficient microsupercapacitor (MSC) device. To achieve a stable and high-voltage window, a non-aqueous gel polymer electrolyte (GPE) of TEABF4/EC/PC/PVDF is optimized. At room temperature, the GPE exhibits high ionic conductivity of ~10.58 mS cm−1 with exceptional mechanical stability. A symmetric supercapacitor based on TiCrN sandwich structure (TiCrN-SS) is fabricated with TEABF4 GPE for practical application. The TiCrN-SS device works on a high voltage of 3.1 V and exhibits good electrochemical properties. The device shows a high energy density of 1.9 μWh cm−2 (5.9 Wh kg−1) at a power density of 109 μW cm−2 (0.34 kW kg−1). To utilize the excellent performance of TiCrN-SS as a miniaturized power source, an on-chip MSC is subsequently fabricated by patterning planar interdigitated TiCrN-microelectrodes. The constructed on-chip TiCrN microsupercapacitor (TiCrN-MSC) works on a wide voltage window of 0–3.1 V while maintaining an optimum areal capacitance of ~500 μF cm−2 at 0.07 mA cm−2 current density. The device exhibits an areal energy density of ~0.7 μWh cm−2 with an optimum 169.02 μW cm−2 power density. This remarkable electrochemical performance and exceptionally wide voltage window of TiCrN-based MSC makes it a potential candidate for direct use as a miniaturized power source in microelectronic devices.