LAUSR

Electrolytic capacitors and batteries are the largest components in portable electronics. Can they be replaced by fully integrated devices capable of performing functions ranging from energy storage to AC line-filtering and providing power pulses for communication? Wearable, flexible, transparent and epidermal electronics, micro-robots, and Internet of Things devices, will all require compact energy storage solutions. Monolithic, on-chip integrated MXene micro-supercapacitors (MSCs) free of separators and electric wires may offer a solution. More than a decade ago, carbon-based on-chip MSCs demonstrated their ability to operate at very high rates and harvest/deliver energy in milliseconds [1–3]. However, several barriers stood in their path. They had a fairly low energy density due to the doublelayer charge storage mechanism, their internal resistance limited the number of devices that could be connected in series, and depositing electrolytes precisely on densely-packed MSCs while ensuring electrochemical isolation was a major challenge. In addition, electrochemical