In a world increasingly reliant on miniaturized electronic devices, the need for efficient energy storage solutions for self-powered microsystems has become paramount. These microsystems, including wearable electronics, MEMS, and WSNs, serve critical functions in various sectors, from healthcare to environmental monitoring and the Internet of Things (IoT). However, the challenge lies in providing these small-scale devices with reliable and long-lasting energy autonomy.
The traditional approach of using micro-batteries, such as Li-ion batteries, faces limitations, including inefficiency for high-power demands and finite lifetimes. These drawbacks make them impractical for applications involving numerous network nodes, where maintenance and component replacement become problematic. As an alternative, micro-supercapacitors have emerged as a promising solution. These devices, unlike micro-batteries, offer rapid charging and discharging, along with a nearly unlimited lifespan.
Three-dimensional pseudocapacitive ruthenium oxide led to the development of all-solid-state micro-supercapacitors with exceptional energy density. However, the use of ruthenium in these micro-supercapacitors raised concerns about cost and sustainability. To address these issues, the 3D-APP project proposed a shift to manganese dioxide (MnO2) electrodes, a cost-effective and abundantly available alternative. The goal is to deposit MnO2 as a thin film on nickel-based nanostructures, overcoming MnO2's low conductivity and achieving stability over extended periods.
Using ionic liquid electrolytes further extended the potential of MnO2 micro-supercapacitors by enabling extended cell voltage. The groundbreaking nature of this project comes with inherent risks, mainly concerning the achievement of performance targets.