Synergistic Trimodal Stimuli-Induced Impedance Matching in Polydopamine-Functionalized Magnetoelectric Nanogenerators: Toward Efficient Charge Generation and Hybrid Energy Harvesting

A trimodal piezo-pyro-magnetoelectric nanogenerator (PPyMENG) is introduced, comprising an electrospun poly(vinylidene fluoride) (PVF₂) nanofiber mat uniformly embedded with polydopamine-coated cobalt ferrite (PCFO) nanoparticles to integrate piezo-, pyro-, and magnetoelectric responses in a single compatible platform. In the PVPCF composite nanofiber mat, the electroactive β-crystalline phase provides coupled piezo- and pyroelectric functionality.

The magnetoelectric pathway arises from the coupling between the molecular ferroelectric dipoles of PVF₂ and the uniformly distributed magnetostrictive PCFO nanoparticles, establishing three parallel energy-conversion channels that collectively reshape the impedance-matching landscape. For instance, simultaneous mode activation reduces the internal resistance from 1.9 MΩ (under mechanical stimuli alone) to 700 kΩ under the combined excitation of mechanical, thermal, and magnetic stimuli, corresponding to a net decrease of 63%, accompanied by a 176% enhancement in output power density.