Triarylmethyl cation redox mediators enhance Li–O2 battery discharge capacities
Journal Article
·
· Nature Chemistry
- Univ. of Illinois, Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States); SLAC
- SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Argonne National Laboratory (ANL), Argonne, IL (United States)
- Univ. of Illinois, Chicago, IL (United States); Argonne National Laboratory (ANL), Argonne, IL (United States)
A major impediment to Li–O2 battery commercialization is the low discharge capacities resulting from electronically insulating Li2O2 film growth on carbon electrodes. Redox mediation offers an effective strategy to drive oxygen chemistry into solution, avoiding surface-mediated Li2O2 film growth and extending discharge lifetimes. As such, the exploration of diverse redox mediator classes can aid the development of molecular design criteria. Here, in this work, we report a class of triarylmethyl cations that are effective at enhancing discharge capacities up to 35-fold. Surprisingly, we observe that redox mediators with more positive reduction potentials lead to larger discharge capacities because of their improved ability to suppress the surface-mediated reduction pathway. This result provides important structure–property relationships for future improvements in redox-mediated O2/Li2O2 discharge capacities. Furthermore, we applied a chronopotentiometry model to investigate the zones of redox mediator standard reduction potentials and the concentrations needed to achieve efficient redox mediation at a given current density. We expect this analysis to guide future redox mediator exploration.
- Research Organization:
- Argonne National Laboratory (ANL), Argonne, IL (United States); SLAC National Accelerator Laboratory (SLAC), Menlo Park, CA (United States)
- Sponsoring Organization:
- National Science Foundation (NSF); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Office of Sustainable Transportation. Vehicle Technologies Office (VTO); USDOE Office of Science (SC)
- Grant/Contract Number:
- AC02-06CH11357; AC02-76SF00515
- OSTI ID:
- 1996583
- Journal Information:
- Nature Chemistry, Journal Name: Nature Chemistry Journal Issue: 9 Vol. 15; ISSN 1755-4330
- Publisher:
- Nature Publishing GroupCopyright Statement
- Country of Publication:
- United States
- Language:
- English
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