Simultaneously realizing ultra-high energy density and discharge efficiency in PVDF composites loaded with highly aligned hollow MnO2 microspheres

Enhancing the energy density and discharge efficiency of dielectric poly(vinylidene fluoride) (PVDF) has long been a challenging task to realize their practical application as advanced electrostatic capacitors. Herein, in this work, we demonstrated a facile yet effective approach to simultaneously strengthen the energy density and discharge efficiency of PVDF through the synergy of optimized fabrication process and introduction of aligned MnO2 hollow spheres. First, using a nonequilibrium manufacturing approach involving electrospinning, hotpressing and hot-rolling, reduced ferroelectric loss and improved breakdown strength was achieved in PVDF, which were advantageous to enhance the energy density and discharge efficiency. By further introducing oriented MnO2 microspheres, one could boost the discharge energy density up to 36 J/cm(3) while maintain the high discharge efficiency of 73% (500MV/m) due to the enhanced interfacial coupling effect and suppressed conduction loss. This work provides a new paradigm to explore high performance PVDF based composites as viable dielectrics for electrostatic capacitors.