Photopatternable hydroxide ion electrolyte for solid-state micro-supercapacitors

Electrochemical energy storage (EES) devices that provide high power and energy for micropower systems are considered to be essential for developing micro/nano electronics such as nanorobotics, environmental sensors, and connected smart electronics. One promising research direction in this field has been to develop on-chip EES devices whose length scales integrate with those of miniaturized electronic devices. In the work described here, we provide the first report of a hydroxide-ion-conducting solid electrolyte that can be patterned using standard lithography. By combining a negative photoresist with a polymerizable ionic liquid, we obtain a thermally and dimensionally stable, hydroxide-ion-conducting solid electrolyte with a conductivity of 10 mS cm−1. Patterning the solid electrolyte directly on interdigitated vanadium nitride (VN) electrodes enables a scalable fabrication approach for producing high-resolution, solid-state VN micro-supercapacitors (MSC) in both single and multiple devices.