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

## TL;DR

This paper explores how using different ions in tiny pores can create diverse functions in ionic devices for brain-like computing.

## Contribution

The study reveals that electrochemical diversity in barrier-limited transport leads to functional diversity in ionic devices.

## Key findings

- Voltage-inactivated transport and electrochemical pulse generation are observed in multi-ionic transport.
- The design space for ionic devices scales exponentially with the number of ion species.
- Diverse behaviors like synaptic potentiation emerge from mixed-ion transport through small pores.

## Abstract

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 2Nion, 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.

Mixed‐ion transport through Å‐scale pores exhibits various functions, including voltage activation, voltage inactivation, nanopulse generation, and synaptic behavior. Our work reveals that one of the fundamental advantages of ionic computing over electronic computingthe diversity of charge carriersdirectly translates into functional diversity in the barrier‐limited regime.