Fast Li-Ion Transport in Amorphous Li2Si2O5: An Ab Initio Molecular Dynamics Simulation

The present study reports an ab-initio molecular dynamics (AIMD) simulation of ionic diffusion in the amorphous Li2Si2O5 in a temperature range of 573-823 K. The results show that the amorphous Li2Si2O5 is primarily a Li+ conductor with negligible O-2 and Si4+ contributions. The obtained activation energy of 0.47 eV for Li+ diffusion is higher than Na+ in the analogue amorphous Na2Si2O5, but close to other types of Li+ conductors. The predicted Li+ conductivity is on the order of 10(-2) S . cm(-1) at 623-823 K. Our simulations also reveal that Li+ in the amorphous Li2Si2O5 diffuses via a hopping mechanism between the nearest sites in the channels formed by two adjacent SiO4 layers. (C) The Author(s) 2016. Published by ECS. All rights reserved.