Session: 16-01-01: Government Agency Student Poster Competition

Paper Number: 149926

149926 - Electrochemical Performance of Aqueous Zinc-Ion Battery Cathodes at Diverse Temperatures 

Fossil fuels, though easy to control and store for electricity generation, are unsustainable and have severe environmental impacts. More renewable sources like wind and solar have fluctuating generation cycles, which necessitate grid-level energy storage to make them viable replacements. Battery installations have the potential to smooth out these short-term grid-level fluctuations, but cost and sustainability have limited their widespread adoption. Lithium-ion batteries have high capacity and round-trip energy efficiency, but they are expensive, contain flammable organic electrolytes, suffer severe capacity degradation at low temperatures, and are not environmentally friendly. Research into economically and environmentally sustainable alternative battery chemistries is critical to enabling the complete transition to renewable energy sources.  An aqueous zinc-ion battery (AZIB) presents one such potential alternative.

The zinc metal anode has a high theoretical capacity of 820 mAh/g and can be used in an aqueous electrolyte, eliminating many safety concerns and offering the added benefit of being inexpensive and abundant. Current cathode materials for AZIBs which demonstrate both high experimental capacity and reversibility are very limited, however. Transition metal oxides such as vanadium pentoxide (V2O5) and manganese dioxide (MnO2) have often been explored in literature for their high theoretical capacities of 589 mAh/g and 617 mAh/g respectively. These are still inexpensive materials in comparison to the nickel, cobalt, and lithium used in lithium-ion battery cathodes, but the observed capacity is often around half the theoretical capacity, partially due to insufficient understanding of the mechanisms [1]. A better understanding of the charge storage and degradation mechanisms could allow these cost-effective cathode materials to reach closer to their theoretical capacity, retaining the value proposition of an AZIB. This project aims to provide insights into the mechanisms of degradation and charge storage by analyzing AZIBs over a range of temperatures.

We conducted a series of experiments using cyclic voltammetry (CV) to analyze the electrochemical performance of V2O5 cathodes at temperatures from 0°C to 50°C. CV was chosen for the depth of insight it offers into the redox processes beyond the standard galvanostatic measurements performed in literature studies of AZIBs at different temperatures. To prepare the cathode material, a slurry of ball-milled V2O5, conductive carbon, and PVDF binder in a 7:2:1 ratio was applied on an aluminum current collector. A Swagelok-type cell was assembled using a zinc anode, glass fiber separator saturated with a constant amount of 2M ZnSO4 electrolyte, and the cathode material. CV was performed while the cell was held at temperature in an environmental chamber; comparisons between voltammograms from cells run at different temperatures allow us to compare rates of reactions, contributions of different redox processes, and to analyze degradation mechanisms. Preliminary CV results show temperature-dependent redox behavior in V2O5 cathodes. Further investigation and analysis will help us understand the mechanisms affected by temperature and their impact on the electrochemical performance of V2O5 as a cathode material.

1. Fang, G., Zhou, J., Pan, A., and Liang, S., 2018, "Recent Advances in Aqueous Zinc-Ion Batteries," ACS Energy Letters, 3(10), pp. 2480-2501. DOI: 10.1021/acsenergylett.8b01426.

Presenting Author: Hunter Maclennan Oregon State University

Presenting Author Biography: Hunter Maclennan is an undergraduate researcher entering his senior year as a chemistry major at Oregon State University. He has worked with Dr. David Ji at OSU on researching iron-anodes for aqueous batteries and with Dr. Özgür Çapraz at UMBC on aqueous zinc-ion battery cathode materials. After graduation, he plans to pursue a PhD. While his current focus is on aqueous battery systems, his other research interests include the chemistry of aerogels, electrolytic hydrogen production, and f-block chemistry.

Authors:

Hunter Maclennan Oregon State University
Bret Marckx University of Maryland, Baltimore County
Özgür Çapraz University of Maryland, Baltimore County