Lithium rich phosphate glass: Crystallization kinetics, structural and conduction characteristics

Crystallization kinetic studies of Li+ ion conducting mol% 60Li2O–40P2O5 glass indicate a 2-dimensional crystal growth mechanism as compared to the 3-dimensional growth mechanism for LiPO3 glass (mol% 50Li2O–50P2O5). Spectroscopic studies reveal that the structures of these two glass compositions differ considerably resulting in different mechanisms for crystal growth. Isothermal ionic conductivity studies further support 2-dimensional crystallization in mol% 60Li2O–40P2O5 glass. Above the glass transition temperature the ionic conductivity deviates from the usual Arrhenian temperature dependence due to the additional effect of the movement of the phosphate polymeric chains in the glass network. The ionic conductivity of the glass ceramic corresponding to the mol% 60Li2O–40P2O5 glass behaves in an Arrhenian fashion with an activation energy of 1.21 eV, much higher than that of 0.77 eV for the glass. Further, it is established using canonical scaling that the mechanism for ionic conduction is temperature independent.