Controlled synthesis of oxygen-doped rod-shaped boron nitride and its thermal conductivity enhancement properties

Abstract

In the problem of heat dissipation of electronic materials, the traditional heat dissipation technology cannot meet the current demand. The existing liquid-cooled thermal fluid has poor thermal conductivity, which limits its application. Among the methods to improve the thermal conductivity of nanofluids, selecting materials with high thermal conductivity as dispersants is a very effective method. Herein, we report the preparation of an oxygen-doped rod-shaped boron nitride (BN–O). Oxygen-doped rod-shaped boron nitride has a suitable aspect ratio to form an effective thermal conductivity network, which effectively improves the thermal conductivity of the matrix material. In addition, the hydroxyl groups formed after functionalization of the BN-O hydroxyl groups, can form van der Waals forces between the molecules of the water-ethylene glycol solution. This allows the thermally conductive filler to be stably present in the matrix material, thereby increasing the thermal conductivity. Thus BN-O has good thermal conductivity and dispersion, while the morphology of BN-O is regulated by the boron-to-nitrogen ratio of the reactants. Under the same reaction conditions, the BN has a rod-shaped morphology for a boron-to-nitrogen ratio close to 1. Notably, the test results show that the thermal conductivity of the water-ethylene glycol matrix is 0.43W/m·K. After adding the same amount of BN-1, BN-2, BN-3, BN-4, BN-O-1, BN-O-2, BN-O-3, and BN-O-4 as thermally conductive fillers, the thermal conductivity are 0.68 W/m·K, 0.61 W/m·K, 0.5 W/m·K, 0.52 W/m·K, 0.97 W/m·K, 0.81 W/m·K, 0.76 W/m·K, and 0.77 W/m·K, respectively. The thermal conductivity is increased by 56.69%, 41.48%, 16.27%, 20.93%, 122.23%, 87.15%, 75.48%, and 77.56% with the addition of thermally conductive filler compared with the matrix. Therefore, oxygen-doped rod-shaped boron nitride can be a competitive candidate for high thermal conductivity additives in water-based.