Accelerating Electrolyte Design ProcessVijay Murugesan, Zimin Nie, Xiaoliang Wei, Aaron Hollas, Wei Wang & Vince Sprenkle

Electrochemical Materials & Systems Group,

Pacific Northwest National Laboratory,

Richland, WA 99352

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Objectives:

Ability to predict the solubility, stability, redox potential and

overall performance of redox flow battery electrolytes

Develop screening procedure using combined computational and

experimental methods to evaluate and identify the optimal solvents,

additives and redox active molecules

Designing vanadium based electrolytes:

Summary and Perspective:

Ion solvation study reveals, thermally activated precipitation of V5+

electrolyte can be suppressed through inhibiting deprotonation

process and/or perturbing the formation of higher order oligomers.

Acknowledgements

This work is supported by the U.S. Department of Energy (DOE) Office of Electricity

Delivery and Energy Reliability under contract No. 57558. PNNL is a operated by

Battelle Memorial Institute for the DOE under contract DE-AC05-76RL01830

Contact: Vijay Murugesan

Electrochemical Materials & Systems Group

Energy & Environmental Directorate

Pacific Northwest National Laboratory

Email: vijay@pnnl.gov

Tel: (509)-371-6540

References:

1. Advanced Energy Materials 1 (3), 394-400, 2011.2. Journal of Power Sources 196 (7), 3669-3672, 2011.3. Advanced Materials 26 (45), 7649-7653, 2014.4. Nature communications 6, 6303, 2015.5. ChemPlusChem 80 (2), 428-437, 2015.

Designing organic-aqueous electrolytes:

Vanadium solvation structure and ligand exchange dynamics dictates

the functional properties of electrolyte.

Designing bi-additives that can enable precise tuning of ion solvation

and subsequently optimal battery performance.

51V NMRTuning V5+ solvation – Bi-additives

[V.6H2O]+2 [V.6H2O]+3 [VO.5H2O]+2[VO2.2H2O]+1

Designing mixed acid flow battery electrolyte through inhibiting

deprotonation reaction of V5+ solvation with chloride substitution. Density functional theory (DFT) based computational screening method

is adopted to design optimal functional groups by predicting the

solubility and redox potential of organic redox molecules.

Adopting asymmetric molecular structure and charge distribution within

redox molecule through addition of functional groups can significantly

enhance the solubility of organic redox molecules . A vigorous DFT

based screening procedure is developed for optimal electrolyte design.

[VO2.2H2O]+1[VO2.Cl. 3H2O]+1 [VO2.PO4. 3H2O]-2

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Parent and Derivatives

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Solvation Energy

31P NMR

Composition of additive system is critical, as it dictates the rotational and

translational ion dynamics and subsequently solubility and viscosity .

Phosphate rotation Preferential solvation of NH4+

Columbic Potential

V5+ Oligomerization