Aqueous Electrochemical Memristor Based on Reversible Insulating-Layer Dynamics Emulating Neuromorphic Functions

Solid-state memristors and nanochannel-based ionic memristors both have received increasing attention in the field of brain-like computing. However, solid-state memristors (e.g., metallic-insulator-metallic structure) rely on electron dynamics, which results in limited tuning diversity and poor biocompatibility. Ionic memristors function with ion dynamics under solution conditions, while they confront challenges such as complex structures and limited memory capacities. Here, we report an ion transport coupled electron transfer-based "electrochemical memristor" in an aqueous electrolyte, which simply consists of two electrodes. This memristor is based on the reversible formation and depletion of the insulating layer on the electrode surface, resulting in an ON/OFF ratio exceeding 1000 and a memory retention time larger than 7 days. The excellent properties allow this electrochemical memristor to realize various neuromorphic functions, including the remembering and forgetting of information, the chemical modulation of synaptic activities, and the localized and global manipulation of neural network dynamics. This research highlights the potential of electrochemical memristors for constructing high-performance neuromorphic computing architectures.