Reinforced Interfaces to Realize Multifunctional Supercapacitors

Today’s electrochemical storage devices are restricted in capacity, a key challenge that limits the operational time of wireless devices. To increase the energy storage capacity, multifunctional structures such as structural supercapacitors combine load-bearing and energy-storage functions into the same device, resulting in weight savings and safety improvements. To achieve an efficient structural supercapacitor, we developed strategies based on interfacial engineering to improve both the electrodes and electrolytes.<br/><br/>The structural electrodes were reinforced by coating carbon-fiber weaves with a uniquely stable conjugated redox polymer and reduced graphene oxide that raised pseudocapacitive capacitance and tensile strength. The solid polymer electrolyte was tuned to a gradient configuration, where it facilitated high ionic conductivity at the electrode-electrolyte interfaces and transitioned to a composition with high mechanical strength in the bulk for load support. The gradient design enabled the multilayer structural supercapacitors to reach state-of-the-art performance matching the level of monofunctional supercapacitors (Science Advances 2023, 9, eadh0069)<br/><br/>Lastly, as a feasibility study, we fabricated a structural supercapacitor to serve as the weight-bearing hull of a model boat. The boat was integrated with a solar panel for charging up the supercapacitor hull, which in turn powered up the boat motor to cruise across a pool. This demonstration showed the potential of structural supercapacitors to facilitate mass savings and increase the capacity for energy harvesting and storage in future electric systems.