BaTiO3-assisted exfoliation of boron nitride nanosheets for high-temperature energy storage dielectrics and thermal management

Abstract Currently, massive preparation of boron nitride nanosheets (BNNSs) towards large-size and good structural integrity via ball milling remains a key challenge, limiting its extensive applications in thermal management and energy storage. Low-cost and recyclable BaTiO3 nanoparticles with good piezoelectric effect can concurrently act as collision buffers and strong reductants to suppress the in-plane crystal structure damage and surface oxidation triggered by high-energy mechanical impact. Herein, an environmentally friendly, simple to operate and easy to realize industrial production method, referred to as BaTiO3-assisted ball milling (BTABM), is demonstrated to prepare high quality few-layered BNNSs with an average lateral size of 0.56 μm and a high yield of 91.2%. This milling process involves the synergetic effects of mechanical shear and mechanochemical peeling provided by deformed BaTiO3. The incorporation of the prepared BNNSs into the P(VDF-CTFE) matrix by BTABM effectively improved simultaneously the dielectric properties and breakdown strength of the ternary P(VDF-CTFE)/BaTiO3/BNNS nanocomposites as well as their thermal management capability, due to the formation of 3D BNNS networks. This novel method provides a guidance for not only scalable exfoliation of other layered 2D materials but also massive fabrication of polymeric nanocomposites applied in high-temperature energy storage devices.