Reflow Soldering-Resistant Solid-State 3D Micro-Supercapacitors Based on Ionogel Electrolyte for Powering the Internet of Things

The fabrication of all solid-state 3D micro-supercapacitor is challenging for powering connected and miniaturized emerging electronics devices in the frame of the future Internet of Things paradigm. Here we highlight the design of a specific solid electrolyte based on ethylmethylimidazolium bis(trifluoromethanesulfonate)imide confined within polyvinylidenefluoride which enables to meet the requirements of safety, easy packaging, and leakage free 3D micro-supercapacitors. This ionogel-based microdevice (2 mm × 2 mm footprint area) exhibits good cycling stability over 30 000 cycles with an areal energy density of 4.4 μWh.cm⁻² and a power density of 3.8 mW.cm⁻². It can also sustain the high temperature reflow soldering process (∼250 °C–5 min) without damage, which is performed to directly bond surface mounted miniaturized devices onto printed circuit boards. This strategy not only provides a reference for the design of high-performance 3D interdigitated micro-supercapacitors, but also paves the way to their further implementation in miniaturized electronic chips for Internet of Things applications.