| Analysis on the Formation of Li4SiO4 and Li2SiO3 through First Principle Calculations and Comparing with Experimental Data Related to Lithium Battery |
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Chil-Hoon Doh, Angathevar Veluchamy, Min-Wook Oh, Byung-Chan Han |
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Korea Electrotechnology Research Institute;Central Electrochemical Research Institute;Department of Energy Systems Engineering, DGIST;Department of Energy Systems Engineering, DGIST; |
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| Abstract |
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The formation of Li-Si-O phases, $Li_4SiO_4$ and $Li_2SiO_3$ from the starting materials SiO and $Li_2O$ are analyzed using Vienna Ab-initio Simulation (VASP) package and the total energies of Li-Si-O compounds are evaluated using Projector Augmented Wave (PAW) method and correlated the structural characteristics of the binary system SiO-$Li_2O$ with experimental data from electrochemical method. Despite $Li_2SiO_3$ becomes stable phase by virtue of lowest formation energy calculated through VASP, the experimental method shows presence of $Li_4SiO_4$ as the only product formed when SiO and $Li_2O$ reacts during slow heating to reach $550^{circ}C$ and found no evidence for the formation of $Li_2SiO_3$. Also, higher density of $Li_4SiO_4$(2.42 g $ml^{-1}$) compared to the compositional mixture $1SiO_2-2Li_2O$ (2.226 g $ml^{-1}$) and better cycle capacity observed through experiment proves that $Li_4SiO_4$ as the most stable anode supported by better cycleabilityfor lithium ion battery remains as paradox from the point of view of VASP calculations. |
| Key Words:
Silicon monoxide, Graphite, $Li_4SiO_4$, $Li_2SiO_3$, Li-Si-O, VASP |
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