Ultracapacitive bioactive-ion pumps

Organisms manipulate ions to perform physiological functions and adapt to environmental changes. Carbon-based capacitive ion-controlled devices mimic biological processes in organisms to construct iontronic devices with specific functions. In this work, we propose a novel carbon-based ultracapacitive device for bioactive-ion pumping. Designer electrolytes are evaluated to investigate the individual electrosorption characteristics of cations and anions via characteristic UV absorption bands in the presence of electrically polarized nanoporous carbons in situ. We identify two distinct charge-balancing mechanisms: in a transient situation, counterion adsorption is the dominant pathway, whereas co-ion desorption is an essential mechanism in the case of pre-equilibrated electrodes. Highly loaded pre-equilibrated electrodes are proposed as a technological foundation for the electrically modulated release of ions (i.e., ion pump). Our electrolyte systems’ unprecedented ability to track individual ion dynamics in real time significantly improves analytical simplicity and detection sensitivity, which is a major step toward next-generation bioelectronic and iontronic technologies.