Initial-Capacitance-Regulated Iontronic Pressure Sensor with Pressure-Activated Interfacial EDL Reconstruction for Wearable Voice Interaction

Iontronic pressure sensors (IPSs) have attracted considerable attention for low-pressure detection owing to the large interfacial capacitance generated by electrical double-layer (EDL) formation. However, the inherent wettability of ionic media often causes the device to form a relatively high initial capacitance ( C 0 ) under pressure-free conditions, which limits the achievable sensitivity. Herein, a hierarchical fibrous network strategy was proposed to regulate C 0 and activate pressure-triggered EDL reconstruction. C 0 was effectively reduced by limiting the initial ionic medium/electrode contact area, while pressure-induced pore compression enlarges the effective interfacial area and rapidly enhances EDL capacitance. Thus, a flexible pressure sensor composed of a PVDF-HFP nanofiber membrane and ionogel (PNMI) was ultimately developed with an ultrahigh sensitivity of 179.44 kPa –1 over 0–15 kPa. Thus, it enabled accurate pressure signal detection. Assisted by random forest, a highly accurate recognition of seven voice commands was achieved, with an accuracy of 98.5%, demonstrating its potential for wearable human–machine interfaces.