NOVELTY - A nano-tube composite polymer electrolyte composition comprises a polymer substrate having main- and side-chains, which at least have an ether group, an acyl group, an amino group, a fluoro group or a Lewis base functional group; a metal salt comprising a metal cation and an anion; and a nano-tube modifier forming Lewis acid-base force with the substrate and the polymer salt complex. The metal salt and the substrate form a polymer salt complex.    USE - For high-energy lithium secondary cell or other electrochemical devices, e.g. super capacitors or sensors.    ADVANTAGE - The inventive nano-tube composite polymer electrolyte composition has excellent ionic conductivity, and good mechanical and process properties.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (A) a method for fabricating a nano-tube composite polymer electrolyte, comprising mixing a nano-tube modifier and an anhydrous solvent and adding a polymer substrate in the mixture, heating and completely stirring the nano-tube modifier and the polymer substrate for generating a polymer electrolyte, and putting the polymer electrolyte in a container and removing the solvent for forming a film;    (B) a method for fabricating a solid-state polymer electrolyte film comprising mixing a nano-tube modifier and an anhydrous solvent and adding a metal salt and a polymer substrate, heating and completely stirring the nano-tube modifier, the anhydrous solvent, the metal salt and the polymer substrate for generating a uniform solution, coating the uniform solution on a plate electrode, a container or a surface of an object, and removing the solvent for forming a polymer electrolyte film; and    (C) a method for fabricating a nano-tube titanium (IV) oxide (TiO2) comprising uniformly mixing a TiO2 powder and a strong base liquid, heating and cooling downing to room temperature for forming a solution with solid powder, and washing the solid powder with acid solution and washing the solid powder with de-ionized water until a solution pH value is near to neutral for generating nano-tube TiO2.    The stirring step is performed with the assistance of microwaves or ultrasonics.    DESCRIPTION OF DRAWING(S) - The figure is a relationship between temperature and conductivity of experiments 2, 15, 17 and 19.