Energetics of silica lithiation and its applications to lithium ion batteries

LENER, G.; OTERO, M.; BARRACO, D.E.; LEIVA, E.P.M.

ELECTROCHIMICA ACTA

PERGAMON-ELSEVIER SCIENCE LTD

Año: 2018 vol. 259 p. 1053 - 1058

0013-4686

Silica based materials are important candidates as anodes for lithium ion batteries due to their highspecific capacity, low production and material cost and abundance in the earth crust. Silica lithiationleads to reversible and irreversible reactions to produce silicon, lithium oxide and lithium silicates. Thefinal composition of these products confers a variety of electrochemical performances, particularlyconcerning their specific capacity and stability/cyclability of the electrodes. Knowledge on the thermochemistryof these reactions is relevant to analyze the thermodynamic stability and potential occurrenceof the different phases. In this work, the free energy of reaction for the lithiation of silica is calculated fordifferent products. The present first principles studies indicate that the formation of products is a highlyexothermic and endergonic process in all cases. In the case of SiO2 lithiation, the free energy shows thatthe reaction to form Li2Si2O5 is highly exothermic, having the greatest probability of formation. Thelithiation potentials and stability of different products are analyzed in the context of experimental resultsfrom the literature.