Rationally engineered interdigitated electrodes with heteroatom doped porous graphene and improved surface wettability for flexible micro-supercapacitors

Micro-supercapacitors (mSCs) are crucial components for the miniaturization of electronic devices and the growing demand for portable, wearable, and Internet-of-things (IoT) technology. Among these, electric double-layer mSCs (EDL mSCs) stand out with their rapid charge/discharge capability and extended lifespan. Porous graphene structure has been utilized to EDL-mSCs due to their compatibility with various substrates and ease of integration. However, methods to increase the performance of the EDL-mSCs based on the porous graphene electrode needs to be considered to achieve high performance flexible mSCs. In this study, we introduce rationally designed, heteroatom doped porous graphene electrodes, incorporating highly electrochemical active nitrogen sites (such as pyrrolic-, pyridinic-, and graphitic-N sites), that greatly enhances the performance of the flexible mSCs. The method involves directly laser scribing polyimide film coated with a phthalocyanine-based dopant, resulting in a remarkable 254 % increase in capacitance and an impressive volumetric energy density of 2.5 mWh cm−3 compared pristine EDL-mSC. This heteroatom-doping strategy improves conductivity and surface wettability and creates more active sites for specific capacitance. Additionally, the heteroatom-doped mSCs exhibit excellent capacitance retention under strain and bending tests, demonstrating their suitability for practical circuit applications. This work offers a simple and effective approach to design flexible and high-performance mSCs, meeting the energy-storage demands of modern electronics and IoT devices.