Volumetrically Accessible Ion-Electron Transduction for High-Fidelity Bioelectronics.

Wearable bioelectronics are essential for continuous health monitoring and rehabilitation, yet existing soft electrodes often lose signal fidelity during prolonged dynamic wear because surface-confined ion-electron transduction offers limited electrochemically addressable volume and charge-buffering capacity. Here, we report a mixed ionic-electronic transduction layer (PGWL) that addresses these limitations through volumetric charge compensation. By maintaining ionic accessibility and electronic continuity within the mixed-conducting network, PGWL supports a stable bulk-engaged ion-electron transduction mode, thereby lowering interfacial impedance while enhancing charge-buffering capability against perturbations. Integrated with a body-temperature-activated biogel for adaptive viscoelastic adhesion and a breathable nanofibrous substrate, the electrode preserves signal integrity under sweat and mechanical interference, achieving a signal-to-noise ratio (SNR) of 30-36 dB with signal variations within 5%. We demonstrate high-fidelity surface electromyography for monitoring weak neuromuscular signals during post-stroke rehabilitation and long-term electrocardiography (ECG) monitoring, establishing PGWL as a modular transduction layer for functionally integrated, high-fidelity wearable bioelectronics.