Nanodiamond-based TiO 2 Nanocomposite Separators for Enhancing Performance of Flexible Paper-based Supercapacitors

Abstract

Supercapacitors (SC) stand out as a storage solution owing to their rapid charge transfer, high power density, low weight, and long lifecycle compared to batteries. Among the SC technologies, interdigitated in-plane SCs offer planar design, compactness, durability, and wide temperature range, which all make them ideal choices for device integration. This work demonstrates the pivotal role of a green, sustainable nanocomposite separator synthesized from detonation nanodiamonds (DND) and TiO₂ nanoparticles in supercapacitor (SC) devices incorporating interdigitated screen-printed carbon electrodes on paper substrates. The TiO 2 @DND nanocomposite provides mechanical and thermal stability and exhibits nanoporous morphology that facilitates ion conduction. The synergic effect between TiO 2 and DND is maximized through hydrogen annealing, which enhances interfacial coupling and reduces charge-transfer resistance. Consequently, the TiO 2 @DND separator enables supercapacitors with high energy and power densities showcasing 597 µF/cm² capacitance and 99% stability after 10,000 cycles, significantly boosting SC performance and durability. These results highlight the potential of nanodiamonds for improving SC devices and potentially also other energy storage technologies.