Boosting Ion Transport in LiBO₂ via Defects Induced by Thermal Neutron Irradiation

Lithium metaborate (LiBO₂) has emerged as an effective cathode coating of Li-ion batteries. Understanding how lattice defects influence its ionic transport is key to optimizing performance. Our previous first-principles calculations predicted that boron vacancies reduce the Li-ion migration barrier, enhancing the ionic mobility. Here, we report experimental evidence supporting this prediction. Thermal neutron irradiation was employed to introduce boron vacancies in LiBO₂, and electrochemical impedance spectroscopy (EIS) reveals enhanced ionic conductivity in a dose-dependent manner, while x-ray diffraction shows no detectable changes in the crystal structure. Scanning electron microscopy (SEM) further confirms dose-dependent microstructural modifications consistent with neutron-induced defect formation. These results demonstrate a clear correlation between irradiation dosage, defect concentration, and ionic transport behavior. Therefore, neutron irradiation presents a viable approach to defect engineering in solids, improving Li-ion conductivity and guiding the design of next-generation protective coatings for battery applications.