On Transferability of Performance Metrics for Redox-Active Molecules

Journal Article · 13 June 2019 · Journal of Physical Chemistry. C

DOI: https://doi.org/10.1021/acs.jpcc.9b02230 · OSTI ID:1559934

Silcox, Benjamin ^[1]; Zhang, Jingjing  ^[2]; Shkrob, Ilya A.  ^[2]; Thompson, Levi ^[1]; Zhang, Lu  ^[2]

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1. Argonne National Lab. (ANL), Argonne, IL (United States); Univ. of Michigan, Ann Arbor, MI (United States)
2. Argonne National Lab. (ANL), Argonne, IL (United States)

Because of their lower material costs, redox-active organic molecules (ROMs) are increasingly used in flow cells. Quantification of their electrochemical stability is important for choosing between different battery chemistries. Ad hoc performance metrics such as cycle numbers have been used to guide materials discovery, but it is unclear whether such metrics are suitable for the intended use. Here, we suggest a kinetic model allowing a narrower definition of cyclability by interpreting it through intrinsic parameters. Using this model, we examine systematic data on cycling and calendar stabilities for dialkoxyarene ROMs in stationary cells. Even for these closely related ROMs, the cycling numbers strongly depend on minor changes in test protocols and structure, which argue against the universality and transferability of these commonly used metrics. Recommendations regarding the standardization of testing protocols are suggested in light of these findings.

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1559934
• Journal Information: Journal of Physical Chemistry. C, Vol. 123, Issue 27; ISSN 1932-7447
• Publisher: American Chemical SocietyCopyright Statement
• Country of Publication: United States
• Language: English