Extraction and usage of free electrons from alkali metals at room temperature

Extracting free electrons from metals is challenging but important for fundamental metal chemistry and future energy applications. The main challenges are electron extraction and stabilization for storage and use. While solvated electrons in liquid ammonia offer a promising approach, their preparation requires harsh conditions below −33.6 °C. Here, we report spontaneous alkali metal (AM) dissolution in tetrahydrofuran (THF) at room temperature, generating stable free-electron solutions. Li, Na, K, and Cs readily dissolve in THF—a widely used organic solvent—producing AM-solutions containing solvated electrons. Mass spectrometry reveals formation of [AM(THF)n]+ complexes (n = 4-10), while X-ray photoelectron spectroscopy confirms the presence of solvated electrons and oxidized metal cations. The favorable reduction potential of THF enables spontaneous AM oxidation, with THF simultaneously stabilizing both extracted electrons and metal cations. We successfully employed AM-solutions for C60 fullerene doping, producing superconducting phases and demonstrating practical utility for materials synthesis. This room-temperature approach overcomes the cryogenic limitations of ammonia-based systems, offering a straightforward method for generating and utilizing solvated electrons under ambient conditions. Extracting free electrons from metals is difficult yet vital for metal chemistry and energy applications. Here, the authors describe spontaneous dissolution of alkali metals in tetrahydrofuran at room temperature, generating stable free-electron solutions that are used for C₆₀ doping to yield superconducting phases and demonstrate their usefulness in materials synthesis.