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(abstract)Developing high energy density lithium-air batteries (LABs) with sufficient cycle life is challenging due to the oxidative degradation of various battery components during charging. Lithium nitrate (LiNO3) has been commonly used as the electrolyte salt, both to protect the lithium anode and to generate NO2- anions that function as the redox mediator (RM) to reduce the charging voltage. However, this RM effect only minimally improves cycling performance because only a low NO2- concentration is produced. The use of lithium nitrite (LiNO2) as the supporting electrolyte salt could overcome this limitation. In the present study, 1 M solutions of LiNO3 or LiNO2 were prepared in tetraethylene glycol dimethyl ether (TEGDME) or N-methyl-2-pyrrolidone (NMP) as LAB electrolytes. Walden plots of these electrolytes established a higher degree of dissociation in the NMP, which had a greater dielectric constant, thus enhancing ionic conductivity. Electrochemical impedance spctroscopy determined that a LAB cell incorporating the LiNO2/NMP electrolyte exhibited reduced diffusion resistance during discharge-charge cycling as a consequence of the RM effect of NO2- anions. Microscopic observation and pore distribution analysis of cathodes confirmed that the clogging of pores was minimized with the LiNO2/NMP electrolyte. As a result, the LAB cell using this system showed the best performance, more than doubling the cycle life. Based on these data, LiNO2 is considered to be an effective electrolyte salt for use in LABs.
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Keyword: Li-Air Battery
Date published: 2024-04-11
Publisher: PERGAMON-ELSEVIER SCIENCE LTD
Journal:
- ELECTROCHIMICA ACTA (ISSN: 00134686) vol. 489 144261
Funding:
Manuscript type: Author's version (Accepted manuscript)
MDR DOI: https://doi.org/10.48505/nims.4486
First published URL: https://doi.org/10.1016/j.electacta.2024.144261
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Updated at: 2024-04-19 17:23:53 +0900
Published on MDR: 2026-04-12 08:21:21 +0900