Date of Graduation

Spring 2018

Document Type

Honors Research Project

Degree Name

Bachelor of Science

Major

Chemical Engineering - Cooperative Education

Research Sponsor

Dr. Zhenmeng Peng

First Reader

Jiahua Zhu

Second Reader

Edward Evans

Abstract

Vanadium flow batteries (VFB) are a type of battery that has potential as a grid-scale energy storage solution. An original design for a lab-scale VFB is presented herein, along with a procedure for electrolyte preparation from V2O5 using oxalic acid. The flow cell is constructed from Delrin, Teflon, Kynar, Santoprene, Nafion, graphite plate, and porous carbon. Two diaphragm pumps along with polyethylene, PVC, and Santoprene tubing are used. The active area is 58 cm2. The battery was charged using a DC power supply at a constant current of 4 A with corresponding initial voltage of 5.88 V for 2 h, and subsequently at a constant voltage of 1.6 V with corresponding initial current of 0.120 A for 12 h. A final open circuit potential of 0.75 V was observed. Colors changed from blue (VO2+) to purple (V2+), and green (V3+), indicating unexpected charging behavior. Polarization curves demonstrate a peak discharge power of 28.4 mW/m2 at current density 517 mA/m2 and potential 54.9 mV. Longer discharge tests predict a discharge time of 341 h. This battery did not perform as expected, never reaching a full state of charge due to current densities far below expected values of 10-100 mA/cm2.

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