Interfacial engineering of lithium metal anodes via TEOS-derived artificial SEI and PVDF-HFP polymer layer

Lithium metal has attracted attention as a promising anode material for next-generation secondary batteries owing to its high theoretical capacity (3860 mAh g −1 ) and low electrochemical potential (3.04 V vs. SHE). However, rapid capacity decline and safety issues caused by unstable interfacial reactions and Li dendrite growth significantly limit its practical application. In this study, we proposed a dual protection strategy by forming an artificial solid electrolyte interphase (SEI) using tetraethyl orthosilicate (TEOS) and introducing a poly(vinylidene fluoride- co -hexafluoropropylene) polymer protective layer on the TEOS. The formed uniform organic-inorganic composite coating suppressed dendrite growth and reduced interfacial resistance, significantly enhancing chemical stability. The symmetric cell with dual-layer lithium (DL-Li) showed not only a low charge transfer resistance (50 Ω) but also a lower nucleation overpotential (66.7 mV) than pristine Li, demonstrating higher cycle stability and superior rate performance. Furthermore, the LiFePO 4 /DL-Li battery demonstrated excellent performance and capacity retention across all rates (0.2C, 0.5C, and 1C). These results demonstrate that the synergistic effect of an artificial SEI and a polymer protective layer can significantly enhance the stability of lithium metal electrodes, suggesting that the use of coatings combining organic and inorganic components is an effective strategy for commercialization of high-energy-density batteries. • Dual protection strategy for stable Li metal anode. • Artificial SEI and polymer layers suppress Li dendrite growth. • Dual layer reduces interfacial resistance and enhances Li + transport. • Dual layer Li anode exhibits improved cycling stability and rate capability.