Designing high-performance asymmetric microsupercapacitors for powering miniaturized electronic devices

Abstract

The increasing prevalence of the Internet of Things, wireless sensors, implantable medical devices, and smart wearable technologies has driven the development of miniaturized flexible electronics. Although microsized batteries have been extensively used for commercial applications, they usually suffer from short lifetimes, low power densities, and complex architectures. To overcome these limitations, microsupercapacitors (MSCs) are being developed that possess promising features along with favourable in-plane interdigitated architectural patterns. These characteristics facilitate their integration into micro-scale devices, where they store energy and release power on demand. For the efficient assimilation of MSCs into microelectronics, asymmetric microsupercapacitors (AMSCs) are considered favourable due to their wider operating potential window (1.6–2.4 V). This results in higher energy densities (>100 µWh cm⁻²) than MSCs with symmetric configurations, which have a narrow voltage range (≤1 V). Most of the previous review works have focused on materials or fabrication techniques used for designing and assembling MSCs. However, this review gives a comprehensive perspective on the fabrication of AMSCs through the use of different anodic and cathodic materials that regulate the performance of such devices to a great extent. It also discusses the integration of AMSCs with smart functions such as functional-based sensor devices, photodetectors, AC-line filtering, and photo-switching to develop smart, self-powered systems. These advancements in in-plane asymmetric MSCs are anticipated to create new possibilities for the development of next-generation portable and wearable electronics devices. Despite these developments, a discernible quantitative gap persists in consistently achieving ultrahigh energy densities concurrently with wide voltage windows.