Defect-Engineered Hexagonal Boron Nitride Enables Ionic Conduction for Lithium Metal Batteries

The practical implementation of lithium metal anodes has been hindered by uncontrollable dendrite formation and interfacial instability. This study presents a defect engineering of multiplayer hexagonal boron nitride (h-BN) that enhances ionic conductivity through argon ion irradiation. A cell-level demonstration was performed using commercially available, large-area CVD-grown h-BN films subjected to industrial-scale argon ion implantation. Direct evidence was provided by integration of these exfoliated flakes into a hybrid microfluidic-microelectronic chip, confirming that controlled vacancy defects transform h-BN into an efficient lithium-ion conductor while preserving its intrinsic electrical insulation. The results confirmed improved lithium-metal anode stability, achieving dendrite-free cycling with Li plating/stripping Coulombic efficiencies exceeding 99.5% for about 1000 cycles. Further assembly of irradiated h-BN in lithium-sulfur batteries effectively mitigates the polysulfide shuttle effect, sustaining over 97% specific capacity around 300 cycles. These results establish a robust, scalable interface engineering route for next-generation lithium metal batteries that combine high ionic transport with excellent electrical insulation.