Develoment of Iontronics: Application and Future

Ions are one of the most familiar substances. All living organisms use ions to carry out vital activities. To maintain life, humans use sodium and potassium ions to regulate their body fluid levels, thus "maintain" their circulatory system, and they employ calcium ions to "sense" information such as pain. Additionally, ions are used in the "repair" of biological functions, such as bones and teeth, making it fair to say that ions are involved in all of the complex life processes of humans. Humans also possess receptors like "mechanoreceptors" and "photoreceptors." These receptors convert physical stimuli on the body’s surface into chemical signals, transmitting this information to the central nervous system via sensory nerves. These receptors have the ability to transform energy from mechanics and light into chemical signals (essentially ion control). Thus, living organisms perform sophisticated ion control, and the potential of ions is more diverse than we can imagine. However, we have yet to be able to utilize these advanced ion control technologies actively. Practical applications have largely been limited to "energy storage functions" such as batteries and capacitors (involving electrochemical reactions and ion accumulation and release). We recently found a new function of ions by fixing ions to form the electric double-layer electret, in which an electric charge can retain its semi-permanent charge [1].

Recently, we have discovered that ions can be controlled by cross-correlation energies such as light, mechanical force, and magnetic field, seemingly unrelated to ion control. In these phenomena, by applying cross-correlated energy from mechanical, optical, and magnetic fields to the electric double layer of ionic liquids, 1) the molecular structures of the positive and negative ions that form the ionic liquid or the aggregates of the ionic liquid, change "rapidly" and "softly" 2) the distribution of positive and negative ions forming the electric double layer changes, leading to variations in ionic density, which in turn alters the capacitance of the electric double layer. In this talk, we will show the novel functionality of ions and their application using the cross-correlation energies of ions.

1. S. Ono, The Chemical Record 23(8), 2023, e202300045.

If you would like to meet with Shimpei during his visit, please contact Mareike Neitzel.