Carbon and TiO2 based electrodes with metal alloy electrode for self-powered detection of water
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Date
2023-09-27
Authors
Teo, Jarren Kai Jun
Advisor
Zhou, Norman
Mayer, Michael
Mayer, Michael
Journal Title
Journal ISSN
Volume Title
Publisher
University of Waterloo
Abstract
Self-powered devices are an emerging research field that could be leveraged into many
devices that ordinarily are cost-prohibitive or otherwise high maintenance to utilize. The
emergence of self-powered devices that do not rely on transient sources of power such as
solar or wind further expands the possibilities of such devices. Currently, while many such
devices are theoretically possible, the actual implementation and useable self-generated
sources are experimental at best using proof-of-concept ideas rather than any functioning
and reliable prototyping data. One of these ideas is the concept of using low-cost Metal
alloy and carbon-based electrodes to form a power generating device when exposed to
water. This thesis takes this idea and expands upon it by thoroughly characterizing and
optimizing the different possible electrode material combinations such that it could be used
in a functional device. A carbon-based material, graphite, was chosen based on preliminary
experiments for one of the electrodes. The metal alloy determined to be optimal for
characterization was Magnesium Alloy MgAZ31. The goal to characterize the chosen
material in a power-generating device by measuring its voltage-current curve was achieved
to a level required for informed optimization of a workable device. From the characteristic
curves, optimal global or local power maximums were found when subjected to changes
in electrode dimensions or ambient conditions. These characteristic curves can be useful
in future development of an integrated water detection sensor system. Additionally, the
optimized sensor material was further tested in proof-of-concept level experiments to
detect water-borne additives such as NaCl and phosphate salts as well as water pH level.
This could further broaden the potential capabilities of the material and allow future
development of a water leak sensor to be multi-functional. This work was achieved by
developing a standardized methodology for production of a fixed dimension sensor as well
as creating cross-comparable testing systems for obtaining the characteristic curves of the
sensor. It was found that the graphite when force-pressed serves as the most cost-effective
and most efficient sensor material for producing the voltages and power requirements
needed for the bluetooth low energy (BLE) technology currently. Recommendations for
the diameter, thickness, densities and operating conditions of the sensor were found using
similar testing methodologies and used as a baseline for manufacturing of a BLE water
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sensor. When measured at the most optimal dimensions and ambient conditions, the base
graphite sensor was shown to be the most consistent for high power generation at an output
voltage of ≈1.6V. It was also discovered that the graphite sensor could also be used to sense
other differences such as pH level without discerning acidity or alkalinity as well as some
salts such as phosphate and NaCl. The thesis also indicates the characteristic curves of the
same graphite sensor under varying dimensions, conditions and timespans which can prove
useful for further exploration of other variables associated with the device.