A General Strategy for Exceptionally Robust Conducting Polymer-Based Bioelectrodes with Multimodal Capabilities Through Decoupled Charge Transport Mechanisms

Abstract

Bioelectrodes function as a critical interface for signal transduction between living organisms and electronics. Conducting polymers (CPs), particularly poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), are among the most promising materials for bioelectrodes, due to their electrical performance, high compactness, and ease of processing, but often suffer from degradation or de-doping even in some common environments (e.g., electrical stimulation, chemicals, and high temperatures). This instability therefore severely undermines their reliability in practical application. To resolve this critical issue, a novel strategy of separating electron transfer from electron-ion transduction is proposed. Specifically, chemically derived holey graphene (HG), serving as an ultra-stable mixed ion-electron conductor, is introduced into the CP matrix. The HG can restore the CP's destructed conductive pathways, whilst its porosity and its intercalation by the CP synergically preserve fast ionic and molecular diffusion. The resulting bioelectrode therefore exhibits excellent low impedance, high charge injection capacity, electrochemical activity, and outstanding resilience to various harsh conditions, outperforming HG, reduced graphene oxide, CP, or graphene-coated CP electrodes. Furthermore, this strategy also exhibits broad compatibility with various processing techniques and proves adaptable to other electrode systems, such as stretchable electrodes, paving the way for practical applications in electrophysical capture, neuron modulation, and biochemical analysis.