Leveraging Electrochemical Diversity in Engineering Liquid‐State Ionic Devices for Neuromorphic Computing

Implementing the brain's electrochemical principles in liquid-state ionic devices for neuromorphic computing has gained notable momentum. A unique advantage of such devices is the abundance of ions and molecular species available for electrochemical signaling. In this work, we demonstrate that electrochemical diversity translates into functional diversity within the barrier-limited transport regime, a phenomenon not captured by classical diffusion transport. Using molecular dynamics simulations, we investigate multi-ionic transport through Ångström-scale pores and reveal diverse behaviors, including voltage-inactivated transport, electrochemical pulse generation, and synaptic potentiation. The resulting design space scales exponentially with the number of ion species, as <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:semantics><mml:msup><mml:mn>2</mml:mn> <mml:msub><mml:mi>N</mml:mi> <mml:mtext>ion</mml:mtext></mml:msub> </mml:msup> <mml:annotation>$2^{N_{\text{ion}}}$</mml:annotation></mml:semantics> </mml:math> , yielding an astronomically large number given the existence of more than 100 known ionic species. Our work highlights an extensive, unexplored design space of electrochemical computing devices occurring in the barrier-limited transport regime.