Analysis on the Formation of Li 4 SiO 4 and Li 2 SiO 3 through First Principle Calculations and Comparing with Experimental Data Related to Lithium Battery

Abstract

The formation of Li-Si-O phases, Li4SiO4 and Li2SiO3 from the starting materials SiO and Li2O are analyzed using Vienna Ab-initio Simulation (VASP) package and the total energies of Li-Si-O compds. are evaluated using Projector Augmented Wave (PAW) method and correlated the structural characteristics of the binary system SiO-Li2O with exptl. data from electrochem. method. Despite Li2SiO3 becomes stable phase by virtue of lowest formation energy calcd. through VASP, the exptl. method shows presence of Li4SiO4 as the only product formed when SiO and Li2O reacts during slow heating to reach 550°C and found no evidence for the formation of Li2SiO3. Also, higher d. of Li4SiO4(2.42 g ml-1) compared to the compositional mixt. 1SiO2-2Li2O (2.226 g ml-1) and better cycle capacity obsd. through expt. proves that Li4SiO4 as the most stable anode supported by better cycleability for lithium ion battery remains as paradox from the point of view of VASP calcns. [on SciFinder(R)]