Single‐Source‐Precursor Synthesis of Novel BCN and HfBCN Nanocomposites for Energy Conversion Application

Multicomponent M BCN ceramics, where M represents a transition metal, are garnering increased interest due to their multifunctionality and ultrahigh‐temperature stability. Currently, research on M BCN primarily focuses on its preparation and application in the form of thin films. In this article, we prepared monolithic BCN and HfBCN nanocomposites using a single‐source precursor approach and explored their potential application as thermoelectric materials for energy conversion. Cubic HfB _x C _y N _{1– x – y} nanocrystallites ranging from 10 to 200 nm were formed in situ within amorphous HfBCN materials after sintering at 1600°C. Furthermore, the presence of turbostratic BC _x N _{1– x} phase within the matrix, significantly surpassing the percolation threshold, contributes to both BCN and HfBCN nanocomposites, exhibiting exceptionally high electrical conductivity exceeding 100 S cm ^–1 just at room temperature. A power factor of approximately 40 μW m ^–1 K ^–2 was achieved in HfBCN‐based nanocomposites, setting a record high among polymer‐derived ceramics.