A Sandwich-Structured Piezoelectric Elastomer Containing a Porous Core Layer for Improving Output Performance

Driven by the rapid development of portable and miniaturized electronics, flexible polymer-based piezoelectric nanogenerators (PENGs) have attracted significant attention for stable energy harvesting and self-powered sensing. However, developing materials that simultaneously combine high elasticity with superior piezoelectric output remains fundamentally challenging, owing to the intrinsic trade-off between mechanical compliance and electromechanical coupling. Herein, we demonstrated a sandwich-structured piezoelectric elastomer (STPPE) featuring a porous thermoset polyurethane (TSPU)/P(VDF-TrFE)/PZT core (TPP) and solid TSPU/P(VDF-TrFE) skin layers through a combined approach of physical foaming and laminated structural engineering. By tuning the foaming agent content and curing temperature, the porous morphology can be effectively modulated to optimize the porosity, electroactive phase (β-phase) content, and mechanical properties. The STPPE exhibited a substantially enhanced piezoelectric performance, achieving a V_oc of 62.1 V, a Q of 11.6 nC, a sensitivity of 3.82 V·kPa^-1 under 13 N. At 100 N, the output surged to 80.1 V and 44.7 nC, respectively. A power density of 2.6 µW·cm^-2 was achieved, alongside a highly stable electrical output over 10 000 cycles, demonstrating the promising potential for practical applications. This work presents a robust strategy for fabricating high-performance, lightweight, and elastic piezoelectric composites for next-generation wearable electronics and self-powered sensors.