Solid polymer electrolytes: materials designing and all-solid-state battery applications: an overview

Polymer electrolytes are promising materials for electrochemical device applications, namely, high energy density rechargeable batteries, fuel cells, supercapacitors, electrochromic displays, etc. The area of polymer electrolytes has gone through various developmental stages, i.e. from dry solid polymer electrolyte (SPE) systems to plasticized, gels, rubbery to micro/nano-composite polymer electrolytes. The polymer gel electrolytes, incorporating organic solvents, exhibit room temperature conductivity as high as ∼10⁻³ S cm⁻¹, while dry SPEs still suffer from poor ionic conductivity lower than 10⁻⁵ S cm⁻¹. Several approaches have been adopted to enhance the room temperature conductivity in the vicinity of 10⁻⁴ S cm⁻¹ as well as to improve the mechanical stability and interfacial activity of SPEs. In this review, the criteria of an ideal polymer electrolyte for electrochemical device applications have been discussed in brief along with presenting an overall glimpse of the progress made in polymer electrolyte materials designing, their broad classification and the recent advancements made in this branch of materials science. The characteristic advantages of employing polymer electrolyte membranes in all-solid-state battery applications have also been discussed.