Enhanced energy density for 3D BaTiO3/MF/PVDF nanocomposites in low electric strength

•3D BT/MF/PVDF nanocomposites were prepared and investigated first via combining with an in suit topological reaction and solvothermal reaction.•The electric displacement different of BT/MF/PVDF nanocomposites can reach 1.5309 μC/cm2 at 100 KV/cm under 3 cycle number. The large dmax-dr value is a significant reason to realize the high energy density in low breakdown electric strength.•The 3D structure achieves a huge enhancement of energy density (25.69 times increased) compared with neat PVDF at 100 KV/cm.