Bioactive Ion-Based Switchable Supercapacitors

Abstract

Switchable supercapacitors enable a reversible electrically driven uptake and release of bioactive ions by polarizing nanoporous carbon electrodes. In this work we demonstrate the first example of a bioactive ion-based switchable supercapacitor. Based on choline chloride and nanoporous carbons with defined porosity we unravel the mechanism of physisorption vs. electrosorption by nuclear magnetic resonance, Raman, and impedance spectroscopy. Weak physisorption leads to pronounced electrically driven electrolyte depletion enabling the release and capture of electrolyte ions in highly controllable and reversible manner. A new 4-terminal device structure is proposed, with a main capacitor and a smaller inserted detective capacitor for monitoring bioactive ions electrosorption in situ. Controlling the ion concentration in a printed switchable supercapacitor based on bioactive ions realizes switching down to 8.3% residual capacity.The exploration of electrically driven adsorption mechanisms in printable microdevices will open an avenue of manipulating bioactive ions for the further application of drug delivery, neuromodulation, or neuromorphic devices. Figure 1