Ionic Transportation Induced Electric Field Modulation in Porous Ecoflex/PTFE with Confined Liquid for High-Performance Contact Electrification Power Generation

Flexible nanogenerators hold great potential for wearable electronics and self-powered sensing, but often suffer from limited stability in various surroundings. In this work, a porous Ecoflex/Polytetrafluoroethylene (PTFE) composite with encapsulated liquid is developed, and the working mechanism of electricity generation driven by ionic transportation induced by a changing electric field is investigated. The micrometer-sized PTFE particles and porous structure provide a large specific surface area that increases the transferred charges. The confined liquid within the porous Ecoflex/PTFE, protected by an outer Ecoflex encapsulation layer, ensures stable performance by isolating the device from ambient interference. The working mechanism is attributed to dynamic changes in pore volume and geometry during compression, which create ionic transportation and change non-uniform electric field distributions, leading to charge induction on the electrode. The optimized porous composite device with a volume of 4 cm³ during the pressing-releasing period achieves an open-circuit voltage of 12 V and the quantity of transferred charge of 4 nC—with stable electrical output over 10 000 mechanical pressing-releasing cycles. This device shows high linearity between compression depth/exerted force and output voltage, with excellent sensitivity reaching 0.315 V kPa⁻¹. Demonstrations in wearable sensing confirm reliable detection of finger bending and throat motions.