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Evaluation of cobalt oxides for calcium battery cathode applications
Evaluación las aplicaciones de óxidos de cobalto como cátodo en baterías de calcio

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Torres, Arturo and Barde, F. and Arroyo de Dompablo, Elena (2019) Evaluation of cobalt oxides for calcium battery cathode applications. Solid State Ionics, 340 (115004). ISSN 0167-2738

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Official URL: https://doi.org/10.1016/j.ssi.2019.115004



Abstract

The identification of potential cathode materials is a requirement for the development of a rechargeable calcium based battery technology. In this work, we use Density Functional Theory (DFT) calculations to explore the electrode characteristics of three ternary calcium cobalt oxides with distinct CoeO dimensionality: 3D-Ca2Co2O5 (brownmillerite type structure), 2D-Ca3Co4O9 (a misfit compound) and 1D-Ca3Co2O6 (K4CdCl6 structural type).
For the three compounds calculations predict Co3+/Co4+ voltages in the 3–4 V range, with a volume variation below 8% upon Ca deinsertion. Further Co4+ oxidation is predicted at too high voltages not reachable in practice. The maximum specific capacities are therefore 192 mAh/g (Ca2Co2O5), 165 mAh/g (Ca3Co4O9) and 160 mAh/g (Ca3Co2O6). The potential application of Ca2Co2O5 is discarded based on a large energy barrier for Ca diffusion (1.3 eV). With energy barriers for Ca diffusion of 0.9 eV, the 2D and 1D oxides are appealing as low rate cathode materials. To complete a previous experimental investigation, we have analyzed the reversibility of the Ca deinterclation reaction of 1D-Ca3Co2O6. It is found that a phase transformation takes place upon decalciation driven by the change in the electronic configuration of Co ions (from High Spin-trigonal prismatic Co3+ to octahedral Low Spin-Co4+) and involving the Ca diffusion pathways.

Resumen (otros idiomas)

Estudio computacional sobre las prestaciones de diversos óxidos de Co como electrodo positivo en baterías recargables de Calcio.

Item Type:Article
Uncontrolled Keywords:Calcium battery; Intercalation; Ca2Co2O5; Ca3Co4O9; Ca3Co2O6
Subjects:Sciences > Chemistry > Crystallography
Sciences > Chemistry > Materials
Sciences > Chemistry > Chemistry, Inorganic
ID Code:60303
Deposited On:18 May 2020 07:18
Last Modified:18 May 2020 08:44

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