• Energy Research

AbstractOne limitation of wearable electronics, and at the same time a challenge, is the lack of energy storage devices with multiple functionalities produced using clean and environmental‐friendly strategies. Here, a multifunctional conductive hydrogel containing poly(3,4‐ethylenedioxythiophene) (PEDOT) and alginate is fabricated, to be used as electrodes in supercapacitors, by applying water‐mediated self‐assembly and polymerization processes at room temperature. The interpenetration of both polymers allows the combination of flexibility and self‐healing properties within the same hydrogel together with the intrinsic biocompatibility and sustainability of such materials. Initially, PEDOT:polystyrene sulfonate and alginate aqueous solutions are mixed in two different proportions (1:1 and 1:3) and ionically crosslinked with CaCl2. Subsequently, re‐interpenetration of poly(hydroxymethyl‐3,4‐ethylenedioxythiophene) by anodic polymerization in CaCl2 aqueous solution is achieved. Re‐interpenetrated 1:3 PEDOT/alginate hydrogels show excellent capacitance values (35 mF cm−2) and good capacitance retention. In addition, the electrochemical properties are not significantly changed after many cutting/self‐healing cycles as observed by cyclic voltammetry. Therefore, this sustainably produced hydrogel shows promising properties for use in wearable energy storage devices.

As the demand for wearable consumer and medical devices continues to grow, there is a pressing need for flexible and wearable means of storing electrical energy. This laboratory exercise provides an educational framework for teaching fundamental concepts in materials chemistry and electrochemistry through a practical, hands-on approach, focusing on the development of flexible energy storage devices. Fiber-based supercapacitors offer a promising solution due to their inherent flexibility compared to bulk materials, making them ideal candidates for the electrodes of flexible supercapacitors. In this module, students synthesize flexible fibers composed of carbon nanomaterials and chitosan using wet spinning and subsequently characterize these fibers using electrochemical techniques such as cyclic voltammetry (CV) and galvanostatic charge–discharge (GCD). The final stage involves the fabrication of a solid-state supercapacitor, providing a realistic application of the concepts learned. This educational module bridges the gap between classroom learning and real-world applications, fostering a deeper understanding of advanced materials, electrochemistry, and energy storage technologies. Peer Reviewed

Flexible fibre supercapacitors were fabricated by wet-spinning from carbon nanotube/carbon black dispersions, followed by straightforward surface treatments to sequentially deposit MnO2 and PEDOT:PSS to make ternary composite fibres. Dip coating the fibres after the initial wet-spinning coagulation creates a simple solutionbased continuous process to produce fibre-based energy storage. Well-controlled depositions were achieved and have been optimised at each stage to yield the highest specific capacitance. A single ternary composite fibre exhibited a specific capacitance of 351 F g-1. Two ternary composite fibre electrodes were assembled together in a parallel solid-state device, with polyvinyl alcohol/H3PO4 gel used as both an electrolyte and a separator. The assembled flexible device exhibited a high specific capacitance of 51.3 F g-1 with excellent both chargedischarge cycling (84.2% capacitance retention after 1000 cycles) and deformation cycling stability (82.1% capacitance retention after 1000 bending cycles). Peer Reviewed