Title

Electroactive-Zone Extension In Flow-Battery Stacks

Keywords

efficiency; flow battery; mixed-conductor; semi-solid suspension; slurry electrode

Abstract

Flowable suspensions that conduct both electrons and ions can enable the use of energy-dense electroactive species in flow batteries [M. Duduta et al., Adv. Energy Mater., 1, 511 (2011); Z. Li et al., Phys. Chem. Chem. Phys., 15, 15,833 (2013); F. Fan et al., Nano Lett., 14, 2210 (2014)]. In comparison with conventional flow batteries where electrochemical reactions are confined to a fixed current-collector region, electronically conductive flow electrodes permit electrochemical reactions to extend outside of the physical confines of the stack. We have measured and modeled how mixed-conduction enables an electroactive zone (EAZ, in which electrochemical reactions occur) that is of greater spatial extent than current collectors, the extension being termed side zone, SZ. Electrochemical reactions in SZs can reduce coulombic and energetic efficiency. Here we show that for realistic suspension properties and operating conditions, the added inefficiency is small in practice, and can be further mitigated by using appropriate operating conditions and/or materials choices. For the specific example of a non-aqueous Li4Ti5O12 suspension, we show that EAZ extension contributes less than 1% additional efficiency loss at C/10 rates for current collectors greater than 20 mm long.

Publication Date

1-1-2014

Publication Title

Electrochimica Acta

Volume

147

Number of Pages

460-469

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1016/j.electacta.2014.09.108

Socpus ID

84908011232 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/84908011232

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