Electrochromic device including lithium-rich anti-perovskite material

A method of making an electrochromic (EC) device, comprising:

• providing a light transmissive first substrate;
• providing a precursor mixture comprising at least one lithium salt of a lithium-rich anti-perovskite (LiRAP) precursor material and transition metal oxide nanostructures in a solvent on the first substrate;
• annealing the precursor mixture to form a working electrode on the first substrate;
• providing a light transmissive second substrate;
• forming a counter electrode on the second substrate;
• and
• forming a solid state electrolyte including a polymer material between the counter electrode and the working electrode.