A gelable system is formed by mixing lithium salts and small-molecule ether compounds such as cyclic ether compounds or straight-chain ether compounds, optionally added with inorganic nanoparticles, additives, other solvents and/or electrolytes; a gel system or solid system is formed by interaction between them (such as the formation of new complexes or self-assembly, etc.), and by ring-opening polymerization or polycondensation of the small-molecule cyclic ether compounds, or by addition-fragmentation chain transfer polymerization of the small-molecule straight-chain ether compounds, etc. The gel system or solid system not only has better safety in use than common gel systems or solid systems, but also better adjustability of strength. The strength of the formed gel can be improved from the source by changing composition and type of raw materials. The improvement in the strength enables the gel system to be expanded into the solid system, thereby further extending the application range of the gel system.