Piezoelectric energy harvesters (PEHs) developed from electrospun polyvinylidene fluoride (PVDF) fibers offer flexibility and superior piezoelectric output, making them promising for self-powered systems and sensors. Nonetheless, the electromechanical conversion efficiency of conventional electrospun PVDF fibers is impeded by their limited pressure-strain range. Herein, elastic porous PVDF microspheres are introduced in-situ via electrospinning to craft a piezoelectric membrane with higher compressive strain. The PVDF microspheres are uniformly embedded between the fibers in a sandwich fashion, and their dimension is easily tunable by varying spinning solution's concentration. Moreover, the micropores on the PVDF microspheres created by removing pre-mixed SiO2 template not only elevates the beta crystal content of PVDF to 82.19%, but also improves the compressibility, significantly boosting the piezoelectric output. The microsphere alloyed PVDF PEH delivers a piezoelectric output of 33.0 V and a power density of 8 mu W/cm2, over 5.8 times that of conventional electrospun PVDF membrane, and can consistently charge lithium-ion batteries. Our research unveils a novel strategic path to modify fiber structured PEHs, advancing their applications in self-powered systems. image
