A solid state battery is a type of battery that uses solid electrolytes instead of liquid or gel electrolytes. The solid electrolyte is usually a solid polymer, such as polyethylene or polypropylene. Solid state batteries have many advantages over traditional batteries, including higher energy density, longer life, and better safety. However, solid state batteries are not yet commercially available.How does a solid state battery work? What are the advantages and disadvantages of solid state batteries? What are the challenges to commercializing solid state batteries?