Integrating CoNi nanoparticles encapsulated by few-layer h-BN with excellent thermal conductivity and thermal stability

CoNi nanoparticles (NPs) encased within few-layered h-BN (CoNi@h-BN) were successfully synthesized via annealing freshly prepared metal ammine complexes and KBH4 with flowing nitrogen gas at 900 °C for 2 h. The present method achieved synchronous synthesis of few layer h-BN (c.a. 5-15 layers) and in-situ reduction of metal nanoparticles with defined size. The obtained composites were tested as potential, low-cost thermal conductivity materials, thermostability and magnetic materials. Notably, CoNi@h-BN with thermal conductivity of 205.7 W m−1 K−1 show remarkable chemical inertness even under high temperature up to 481 °C, indicating potential solution for the thermal management of chip-level or package-level. Additionally, metal nanoparticles encased by h-BN behave as a soft magnetic material. Combined with DSC-TG analysis and physicochemical characterization result, a possible formation mechanism of CoNi@h-BN was proposed, and the synthesis strategy may also profit catalysts in the fields of fuel cells, metal-air batteries and electrochemical sensors.