Mechanistic Study of the Li–Air Battery with a Co₃O₄ Cathode and Dimethyl Sulfoxide Electrolyte

Journal Article · Tue Oct 05 00:00:00 UTC 2021 · Journal of Physical Chemistry. C

DOI: https://doi.org/10.1021/acs.jpcc.1c07619 · OSTI ID:1867822

Jiang, Zhen  ^[1]; Rappe, Andrew M.  ^[2]

---

1. Univ. of Pennsylvania, Philadelphia, PA (United States); University of Pennsylvania
2. Univ. of Pennsylvania, Philadelphia, PA (United States)

The lithium–air battery, a powerful competitor to replace the traditional lithium-ion battery, has attracted increasing attention due to its extremely high theoretical energy density. However, its development is limited by the cathode and electrolyte properties, which should include high stability, conductivity, and electrocatalytic properties in oxygen-rich environments. Here, we employ a systematic first-principles study of Li–O₂ discharge and charge reactions on the Co₃O₄-based cathode with the assistance of dimethyl sulfoxide (DMSO) electrolyte. The structure, stability, and electronic properties of different surface reconstructions of the Co₃O₄(100) facet are investigated. In addition, the mechanisms and thermodynamic overpotentials of multi-step reactions between Li⁺/e^– and O₂ are provided, where lithium suboxide products (Li₂O₂ or Li₃O₂) are formed on the different Co₃O₄(100) terminations. The solvation shell of Li⁺ components in explicit DMSO solvent is investigated through ab initio molecular dynamics simulations. In general, we find that the Co₃O₄(100)-O (oxidized) surface is the most stable one under standard conditions, and the stable Li⁺ solvation structure is found in a tetrahedral Li(DMSO)₄⁺ shell in the DMSO-based electrolyte. Moreover, in the system of the Co₃O₄(100)-O cathode and DMSO electrolyte, the solution model pathway is energetically favorable for the Li–O₂ discharge reaction. It provides a low constant overpotential of 0.17 V during a long-term discharging process, thus causing the final toroid Li₂O₂ formation on the cathode. During the charging process, an overpotential of 0.36 V is required to rapidly decompose Li₂O₂.

• Research Organization: University of Pennsylvania, Philadelphia, PA (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: SC0019281
• OSTI ID: 1867822
• Journal Information: Journal of Physical Chemistry. C, Journal Name: Journal of Physical Chemistry. C Journal Issue: 40 Vol. 125; ISSN 1932-7447
• Publisher: American Chemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English