Advances on Microsupercapacitors: Real Fast Miniaturized Devices toward Technological Dreams for Powering Embedded Electronics?

[Image: see text] Microsupercapacitors (MSCs) have emerged as the next generation of electrochemical energy storage sources for powering miniaturized embedded electronic and Internet of Things devices. Despite many advantages such as high-power density, long cycle life, fast charge/discharge rate, and moderate energy density, MSCs are not at the industrial level in 2022, while the first MSC was published more than 20 years ago. MSC performance is strongly correlated to electrode material, device configuration, and the used electrolyte. There are therefore many questions and scientific/technological locks to be overcome in order to raise the technological readiness level of this technology to an industrial stage: the type of electrode material, device topology/configuration, and use of a solid electrolyte with high ionic conductivity and photopatternable capabilities are key parameters that we have to optimize in order to fulfill the requirements. Carbon-based, pseudocapacitive materials such as transition metal oxide, transition metal nitride, and MXene used in symmetric or asymmetric configurations are extensively investigated. In this Review, the current progress toward the fabrication of MSCs is summarized. Challenges and prospectives to improve the performance of MSCs are discussed.