Formation of Hexagonal Boron Nitride by Metal Atomic Vacancy-Assisted B–N Molecular Diffusion

Because of the low solubility of N atoms in metals, hexagonal boron nitride (h-BN) growth has explained by surface reaction on metal rather than by penetration/precipitation of B and N atoms in metal. Here, we present an impressive pathway of h-BN formation at the interface between Ni and oxide substrate based on B–N molecular diffusion into Ni through individual atomic vacancies. First-principles calculations confirmed the formation energies of the h-BN layers on and under the metal and the probability of B–N molecular diffusion in metal. The interface growth behavior depends on the species of metal catalysts, and these simulation results well support experimental results

Bi-Morphological Form of SiO₂ on a Separator for Modulating Li-Ion Solvation and Self-Scavenging of Li Dendrites in Li Metal Batteries

The lithium (Li) metal anode is highly desirable for high-energy density batteries. During prolonged Li plating–stripping, however, dendritic Li formation and growth are probabilistically high, allowing physical contact between the two electrodes, which results in a cell short-circuit. Engineering the separator is a promising and facile way to suppress dendritic growth. When a conventional coating approach is applied, it usually sacrifices the bare separator structure and severely increases the thickness, ultimately decreasing the volumetric density. Herein, we introduce dielectric silicon oxide with the feature of bi-morphological form, i.e., backbone-covered and backbone-anchored, onto the conventional polyethylene separator without any volumetric change. These functionally vary the Li+ transference number and the ionic conductivity so as to modulate Li-ion solvation and self-scavenging of Li dendrites. The proposed separator paves the way to maximizing the full cell performance of Li/NCM622 toward practical application