An ultrathin high-performance heat spreader fabricated with hydroxylated boron nitride nanosheets

An ultrathin, highly thermally conductive heat spreader has been fabricated by layer-by-layer stacking of hydroxylated boron nitride nanosheets (HBNNS) for the first time. HBNNS were prepared by a molten hydroxide-assisted liquid exfoliation from hexagonal boron nitride powder. The as-prepared heat spreader of HBNNS exhibits a high thermal conductivity of 51.1 W m−1 K−1 along the in-plane direction, and can be further enhanced 14% by annealing for de-hydroxylation. This heat spreader with 10–30 µm in thickness possessed excellent thermal stability with negligible weight loss at wide temperature range up to 700 °C, resulting in promising applications for heat dissipation in electronic components operated at high working temperature.