Enhanced flexibility and performance of interdigitated microsupercapacitors through in-situ rGO growth in NiCuSe nanocomposite conductive ink

Microsupercapacitors (MSCs) are promising alternative power sources capable of meeting the growing demand for wearable and on-chip electronics due to their compact size, lightweight nature, exceptional charge-discharge rates, high power densities, and superior flexibility. However, a major challenge in current MSCs development lies in their limited energy density, high-cost, and time-intensive fabrication processes. This study focuses on fabricating flexible interdigitated printed MSCs using in-situ growth of reduced graphene oxide within nickel-copper selenide nanocomposite inks via screen printing. The eco-friendly ink formulation incorporates ethyl cellulose, diacetone alcohol, and a non-ionic surfactant to optimize printability, viscosity, and post-drying efficacy. The MSCs achieved a high areal capacitance of 756.3 mFcm⁻² at 5 mVs⁻¹, with energy densities of 84.4 µWcm⁻² (symmetric) and 151.2 µWhcm⁻² (asymmetric), and corresponding power densities of 406 mW cm⁻² and 1210 mW cm⁻². The printed devices retained 94.2 % of their capacitance on PET (Polyethylene terephthalate) substrates and exhibited excellent mechanical stability under bending, making them ideal for wearable electronics and flexible IoT applications. These results highlight the potential of the fabricated screen-printed MSCs, leveraging the optimized electrode material, as a high-performance and eco-friendly energy storage technology for next-generation flexible electronics.