A method of fabricating a solid polymeric electrolyte having a pattern includes mixing constituents including a liquid electrolyte, a photo-crosslinking agent, and inorganic particles to form an electrolyte paste; dispersing together the constituents of the electrolyte paste; coating the electrolyte paste on a substrate; pressing the electrolyte paste with a patterned mold having a shape to copy the shape of the patterned mold onto the electrolyte paste and provide said pattern; and illuminating an ultraviolet light onto the electrolyte paste to induce a photo-crosslinking reaction and cure the photo-crosslinking agent of the electrolyte paste, wherein said solid polymeric electrolyte includes a polymer matrix having a mesh structure, the polymer matrix being formed of the cured photo-crosslinking agent; inorganic particles distributed in the polymer matrix; and a lithium salt and an organic solvent impregnated between the polymer matrix and the inorganic particles.