CNT array-based aluminum bipolar electrode iontronic memristors

Iontronics has emerged as a compelling platform for neuromorphic computing, where ions serve as functional charge carriers for information processing. Iontronic memristors hold particular promise due to their ability to emulate synaptic signal transmission through history-dependent ion transport. However, most existing devices rely on delicate control of nanochannel geometry and surface chemistry to induce ionic hysteresis, posing challenges for tunability and scalable materials design. Here, we introduce an alternative route to ionic memristive behavior based on asymmetric electrochemical reactions occurring at the poles of a bipolar electrode (BPE). In this system, a carbon nanotube array (ACNT) membrane selectively regulates cation transport on one side of an aluminum BPE, dynamically modifying local reaction environments and producing voltage-dependent enhancement or suppression of the redox current. This coupling between ion-selective nanochannels and reaction kinetics yields pronounced rectification and hysteretic current-voltage responses without requiring precise adjustment of nanoscale confinement. The ACNT-based-aluminum device further mimics short-term synaptic plasticity, demonstrating its capability for neuromorphic emulation. This electrochemically driven strategy establishes a versatile materials framework in which diverse redox chemistries and ion-regulating layers can be combined to construct tunable, solution-operable iontronic memristors.