A rechargeable lithium–oxygen battery with dual mediators stabilizing the carbon cathode

Gao, Xiangwen; Chen, Yuhui; Johnson, Lee R.; Jovanov, Zarko P.; Bruce, Peter G.

Abstract

At the cathode of a Li–O2 battery, O2 is reduced to Li2O2 on discharge, the process being reversed on charge. Li2O2 is an insulating and insoluble solid, leading ultimately to low rates, low capacities and early cell death if formed on the cathode surface. Here we show that when using dual mediators, 2,5-Di-tert-butyl-1,4-benzoquinone [DBBQ] on discharge and 2,2,6,6-tetramethyl-1-piperidinyloxy [TEMPO] on charge, the electrochemistry at the cathode surface is decoupled from Li2O2 formation/decomposition in solution. Capacities of 2 mAh cmareal−2 at 1 mA cmareal−2 with low polarization on charge/discharge are demonstrated, and up to 40 mAh cmareal−2 at rates ≫1 mA cmareal−2 are anticipated if suitable gas diffusion electrodes can be devised. One of the major barriers to the progress of Li–O2 cells is decomposition of the carbon cathode. By forming/decomposing Li2O2 in solution and avoiding high charge potentials, the carbon instability is significantly mitigated ( < 0.008% decomposition per cycle compared with 0.12% without mediators).

Citation

Gao, X., Chen, Y., Johnson, L. R., Jovanov, Z. P., & Bruce, P. G. (2017). A rechargeable lithium–oxygen battery with dual mediators stabilizing the carbon cathode. Nature Energy, 2, Article 17118. https://doi.org/10.1038/nenergy.2017.118

• Journal Article Type: Article
• Acceptance Date: Jun 15, 2017
• Online Publication Date: Jul 31, 2017
• Publication Date: Sep 1, 2017
• Deposit Date: Jul 29, 2020
• Publicly Available Date: Jul 31, 2020
• Journal: Nature Energy
• Electronic ISSN: 1520-8524
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 2
• Article Number: 17118
• DOI: https://doi.org/10.1038/nenergy.2017.118
• Public URL: https://nottingham-repository.worktribe.com/output/3019940
• Publisher URL: https://www.nature.com/articles/nenergy2017118