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Banik, Stephen - PhD Dissertation.pdf (4.88 MB)

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Suppressing Dendritic Growth during Zinc Electrodeposition using Polyethylenimine as an Electrolyte Additive for Rechargeable Zinc Batteries

Banik, Stephen John, II
http://orcid.org/0000-0002-8473-6458
http://rave.ohiolink.edu/etdc/view?acc_num=case1459266964

Abstract Details

2016, Doctor of Philosophy, Case Western Reserve University, Chemical Engineering.
Energy storage devices, e.g., batteries, are central to the United States’ clean energy revolution. Load-leveling batteries are needed to store energy from intermittent renewable energy sources and high energy density batteries are required for electric vehicles and portable electronics. Zinc-air batteries are a promising alternative to the current state-of-the-art lithium-ion batteries. Zinc-air batteries offer high energy densities (about twice the energy density of lithium-ion batteries). The Zinc-air battery anode contains metallic zinc, which is an earth-abundant, environmentally benign metal. The use of aqueous electrolytes makes zinc-air batteries inherently cheaper and safer compared to lithium-ion batteries, which use expensive and flammable organic electrolytes. However, a major roadblock in the development of rechargeable zinc batteries is the dendritic morphology evolution during zinc electrodeposition (i.e., during battery charging). Zinc dendrites can detach from the electrode surface leading to capacity loss or pierce through the separator causing early cell failures. In the present work, polyethylenimine (PEI, M.W. = 800 g/mol) is employed as an electrolyte additive to suppress dendrite formation during zinc electrodeposition from typical alkaline electrolytes used in rechargeable zinc-air batteries. Dendrite suppression is characterized as a function of the PEI concentration in the bulk electrolyte using in situ optical microscopy. Steady-state and transient electrochemical polarization measurements on a rotating disk electrode, combined with electrochemical quartz crystal microgravimetry and scanning electron microscopy reveal the mechanism by which PEI suppresses dendrites. That is, PEI adsorbs on the zinc surface leading to suppression of the zinc electrodeposition kinetics, thereby suppressing activation-controlled dendrite growth. PEI is also effective in suppressing roughness evolution during charge-discharge cycling of zinc anodes. At current densities corresponding to typical zinc-air battery charging rates, PEI does not affect the zinc deposition current efficiency. Additive injection studies coupled with transport-kinetics modeling provides insights into the diffusion and surface-adsorption properties of PEI during zinc electrodeposition. At typical PEI concentrations required for zinc dendrite suppression, PEI adsorption on the electrode surface is limited by its diffusional transport and not by its surface adsorption kinetics. For branched PEI (M.W. = 800 g/mol) in alkaline media, the diffusion coefficient (D_PEI) was measured to be 1.87 x 10^-6 cm^2/s and the adsorption rate constant was estimated to be k_ads >= 0.1 cm/s.
Rohan Akolkar, Ph.D. (Advisor)
Uziel Landau, Ph.D. (Committee Member)
Chung-Chiun Liu, Ph.D. (Committee Member)
Mark De Guire, Ph.D. (Committee Member)
134 p.
Chemical Engineering; Energy
Zinc dendrites; zinc electrodeposition; dendrite suppression; polyethylenimine; additive adsorption; rechargeable zinc battery; zinc-air battery

Recommended Citations

Citations

  • Banik, II, S. J. (2016). Suppressing Dendritic Growth during Zinc Electrodeposition using Polyethylenimine as an Electrolyte Additive for Rechargeable Zinc Batteries [Doctoral dissertation, Case Western Reserve University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=case1459266964

    APA Style (7th edition)

  • Banik, II, Stephen. Suppressing Dendritic Growth during Zinc Electrodeposition using Polyethylenimine as an Electrolyte Additive for Rechargeable Zinc Batteries. 2016. Case Western Reserve University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=case1459266964.

    MLA Style (8th edition)

  • Banik, II, Stephen. "Suppressing Dendritic Growth during Zinc Electrodeposition using Polyethylenimine as an Electrolyte Additive for Rechargeable Zinc Batteries." Doctoral dissertation, Case Western Reserve University, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=case1459266964

    Chicago Manual of Style (17th edition)

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This open access ETD is published by Case Western Reserve University School of Graduate Studies and OhioLINK.