Understanding LiOH Formation in a Li-O2 Battery with LiI and H2O Additives

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.

Kim, GunwooUniversity Of Cambridge (författare)
Jonsson, Erlendur,1983Chalmers tekniska högskola,Chalmers University of Technology,University Of Cambridge(Swepub:cth)erlendur (författare)
Castillo-Martínez, ElizabethUniversity Of Cambridge (författare)
Temprano, IsraelUniversity Of Cambridge (författare)
Shao, YuanlongUniversity Of Cambridge (författare)
Carretero-González, JavierUniversity Of Cambridge,Instituto de Ciencia & Tecnologia de Polimeros (författare)
Kerber, Rachel N.University Of Cambridge (författare)
Grey, C. P.University Of Cambridge (författare)
University Of CambridgeChalmers tekniska högskola (creator_code:org_t)

Av författaren/redakt...: Liu, Tao; Kim, Gunwoo; Jonsson, Erlendu ...; Castillo-Martíne ...; Temprano, Israel; Shao, Yuanlong; visa fler...; Carretero-Gonzál ...; Kerber, Rachel N ...; Grey, C. P.; visa färre...

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