Largely enhanced dielectric and thermal conductive properties of polypropylene composites by adding mixture of exfoliated boron nitride and liquid metal

•A simple strategy was proposed to exfoliate boron nitride (BN) by grinding it in liquid metal (LM).•The one-pot exfoliation product containing exfoliated BN and LM, is directly used as hybrid filler for preparing polypropylene (PP) composites to improve the polarization and heat transfer of composites.•A high dielectric constant of 3.5, high thermal conductivity of 1.9 W/m·K, and low dielectric loss of 0.005, low conductivity of 10−11 S/cm3 are achieved in PP/LM@BN composites.