Lithium metal batteries (LMBs) have emerged as promising next-generation energy storage systems owing to their exceptionally

high theoretical capacity (3860 mAh g−

1) and low electrochemical potential (− 3.04 V vs. SHE). However, practical

implementation of LMBs remains severely limited by unstable lithium interfaces, dendrite formation, and parasitic reactions

associated with liquid electrolytes. Herein, we developed a stabilized gel polymer electrolyte by incorporating boron nitride

nanotubes (BNNTs) into a poly(vinylidene fluoride-co-hexafluoropropylene) matrix. The resulting BNNT-reinforced gel polymer

electrolyte (BNGPE) exhibited enhanced electrolyte wettability, reduced interfacial resistance, a wide electrochemical

stability window (~ 5.4 V), and outstanding thermal durability (up to 200 °C). Symmetric Li/BNGPE/Li cells demonstrated

stable cycling performance with uniform lithium deposition, effectively suppressing dendrite formation over 5500 h without

short-circuiting. Moreover, full-cell testing employing a LiFePO₄ cathode and lithium metal anode delivered a stable, high

specific capacity (~ 163 mAh g−

1) and superior rate performance, especially under elevated-temperature conditions. These

results clearly indicate that optimized BNNT-enhanced gel electrolytes effectively address critical limitations of conventional

electrolyte systems, significantly improving safety, interfacial stability, and electrochemical performance. Thus, this study

presents a viable pathway toward commercializing advanced, high-energy–density, and thermally resilient lithium metal

battery technologies.