Defect Engineering in hBN Micropowder for Electrochemistry and Energy Storage*

Hexagonal boron nitride (hBN) is a chemically and structurally stable wide–band gap insulator (≈5–6 eV), but its poor electronic conductivity limits its use in energy applications. Previous studies show that defect engineering can modify the electronic structure of hBN, creating states that reduce the band gap and increase conductivity. Here, we explore the viability of commercial hBN micropowder by introducing and identifying defect states as a pathway toward reducing the band gap to ~2 eV, with the long-term goal of enabling electrochemical applications in energy storage. Samples were annealed at high temperature to introduce defects, which were tracked using Raman spectroscopy of the E₂g mode near 1366 cm⁻¹, sensitive to shifts and broadening from lattice disorder and defect states. This work represents an initial step in defect engineering of hBN micropowders, establishing an approach to tune their band gap as a pathway toward sustainable electrochemical energy storage applications.