Sicolo, Sabrina ; Fingerle, Mathias ; Hausbrand, René ; Albe, Karsten (2017):
Interfacial instability of amorphous LiPON against lithium: A combined Density Functional Theory and spectroscopic study.
In: Journal of Power Sources, 354, pp. 124-133. ISSN 03787753,
[Article]

Abstract

The chemical instability of the glassy solid electrolyte LiPON against metallic lithium and the occurrence of side reactions at their interface is investigated by combining a surface science approach and quantum-mechanical calculations. Using an evolutionary structure search followed by a melt-quenching protocol, a model for the disordered structure of LiPON is generated and put into contact with lithium. Even the static optimization of a simple model interface suggests that the diffusion of lithium into LiPON is driven by a considerable driving force that could easily take place under experimental conditions. Calculated reaction energies indicate that the reduction and decomposition of LiPON is thermodynamically favorable. By monitoring the evolution of the LiPON core levels as a function of lithium exposure, the disruption of the LiPON network alongside the occurrence of new phases is observed. The direct comparison between UV photoelectron spectroscopy measurements and calculated electronic densities of states for increasing stages of lithiation univocally identifies the new phases as Li_2O, Li_3P and Li_3N. These products are stable against Li metal and form a passivation layer which shields the electrolyte from further decomposition while allowing for the diffusion of Li ions.

Interfacial instability of amorphous LiPON against lithium: A combined Density Functional Theory and spectroscopic study. Available from: https://www.researchgate.net/publication/316112203_Interfacial_instability_of_amorphous_LiPON_against_lithium_A_combined_Density_Functional_Theory_and_spectroscopic_study [accessed May 16, 2017].

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