AN OVERVIEW OF SOLID ELECTROLYTES FOR LITHIUM-ION BATTERIES BASED ON NASICON MATERIALS

Abstract

Lithium-ion solid electrolyte batteries have attracted great attention to replacing liquid electrolytes due to their cycling electrochemical properties, durable stability and safety. Numerous studies have been investigated to increase the performance of ionic-conductivity and enhance the stability of solid-state electrolytes, and its commercialization is broadly spread. This review article highlights the progress in developing NASICON-type solid electrolytes, which are made by solid-state reactions and wet-chemical procedures. Initially, researchers focused on the crystal structure, strength, and electrochemical properties of LiZr2(PO4)3, but recent studies have shifted towards investigating the electrical conductivity, crystal structure and its compatibility with Li metal. Also, the indigenous research on LiTi2(PO4)3 was pivoted on densification of the solid electrolyte to improve ionic conductivity by partial substitution of Ti4+ with Al3+ or B3+ now yields a promising ionic conductivity. LiGe2(PO4)3 is yet another Li-based NASICON electrolyte that, from the early stage, received extensive research majoring on the partial substitution of Al3+ with Ge4+ with the formula Li1+xAlxGe2-x(PO4)3 to stabilize the crystal structure following experimental and computational analysis. Improved ionic conductivity currently increasing as a result of improved Li intensity affected by aliovalent Al3+ substitution. Numerous research efforts have been explored to improve the ionic conductivity and elevate the electrochemical and thermal stabilities of NASICON-type electrolytes. It deems it fit to bring forth a cascade of promising results that so far have been recorded in both the early and the current research efforts in improving the suitability of NASICON-type electrolytes.