Ionic Conductivity in Li-doped Functionalized hBN

Covalently functionalized and doped two-dimensional materials have attracted attention due to their tunable chemical and physical properties and broad technological applicability, such as energy storage. Hexagonal boron nitride (hBN) is of special interest for functionalization due to its mechanical and thermal stability and compatibility with current Li-battery technologies; however, chemical inertness makes functionalization challenging. Using mechanochemical methods, we prepared lithium oxalate–functionalized hBN doped with additional Li. I present the investigation of transport properties with frequency and temperature-dependent impedance spectroscopy. This technique -- enabling the separation of the contributions of different conduction mechanisms -- revealed that the material is a solid-state ionic conductor and an electronic insulator. Furthermore, we observed a second, low-temperature ionic regime, where the conductance is strongly humidity-dependent.