Room-temperature fabricated boron nitride ceramics with superior thermal conductivity

Thermally conductive ceramics represented by boron nitride (BN) are the enabling materials for thermal management in modern electronics. However, their sintering processes are typically energy-intensive, involving ultrahigh sintering temperatures (generally >1700 °C), limiting practical applications. Herein, we introduce an energy-efficient preparation method that rapidly densifies hexagonal BN ceramics at room temperature within minutes. This approach drastically reduces energy consumption—by two orders of magnitude lower than that of traditional high temperature sintering methods, while maintaining the high density. The utilization of boric acid and water clusters facilitates plastic deformation and enhances mass transfer under hydrostatic pressure, significantly lowering the densification activation energy. Consequently, the room-temperature prepared BN ceramics achieve an exceptional thermal conductivity of 62 W m −1  K −1 , outperforming current low-temperature sintered ceramics. These densified bulk BN ceramics have been prototyped in electronic devices for efficient heat conduction, demonstrating great advantages for energy saving and sustainable production in next-generation electronics.