Understanding LiOH Formation in a Li-O2 Battery with LiI and H2O Additives
Journal article, 2019

LiI-promoted LiOH formation in Li-O2 batteries with wet ether electrolytes has been investigated by Raman, nuclear magnetic resonance spectroscopy, operando pressure tests, and molecular dynamics simulations. We find that LiOH formation is a synergistic effect involving both H2O and LiI additives, whereas with either alone Li2O2 forms. LiOH is generated via a nominal four-electron oxygen reduction reaction, the hydrogen coming from H2O and the oxygen from both O2 and H2O, and with fewer side reactions than typically associated with Li2O2 formation; the presence of fewer parasitic reactions is attributed to the proton donor role of water, which can coordinate to O2- and the higher chemical stability of LiOH. Iodide plays a catalytic role in decomposing H2O2/HO2- and thereby promoting LiOH formation, its efficacy being highly dependent on the water concentration. This iodide catalysis becomes retarded at high water contents due to the formation of large water-solvated clusters, and Li2O2 forms again.

Author

Tao Liu

University of Cambridge

Gunwoo Kim

University of Cambridge

Erlendur Jonsson

Chalmers, Physics, Condensed Matter Physics

University of Cambridge

Elizabeth Castillo-Martínez

University of Cambridge

Israel Temprano

University of Cambridge

Yuanlong Shao

University of Cambridge

Javier Carretero-González

Instituto de Ciencia & Tecnologia de Polimeros

University of Cambridge

Rachel N. Kerber

University of Cambridge

C. P. Grey

University of Cambridge

ACS Catalysis

2155-5435 (eISSN)

Vol. 9 1 66-77

Graphene Core1. Graphene-based disruptive technologies (Graphene Flagship)

European Commission (Horizon 2020), 2016-04-01 -- 2018-03-31.

Subject Categories

Inorganic Chemistry

Materials Chemistry

Other Chemical Engineering

DOI

10.1021/acscatal.8b02783

More information

Latest update

2/12/2019