Efficient exfoliation and functionalization of hexagonal boron nitride using recyclable ionic liquid crystal for thermal management applications

•The simultaneous exfoliation and functionalization of BNNS was achieved by ILC-assisted.•Free ILC can be recycled after exfoliation and used to exfoliate the new h-BN.•The functionalized BNNS exhibited remarkable dispersion stability in water and organic liquids.•Multifunctional flexible BNNS/ANF composite papers was prepared via vacuum-assisted filtration.•The paper showed excellent thermally conductive, mechanical properties, flame resistance.