Optimal Galvanic Cell Design for Powering Ingestible Devices in Varying Gastrointestinal Conditions

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KITCHEN-THESIS-2025.pdf (2.52 MB)
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Kitchen, Camden
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Daniel Guggenheim School of Aerospace Engineering
The Daniel Guggenheim School of Aeronautics was established in 1931, with a name change in 1962 to the School of Aerospace Engineering
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https://hdl.handle.net/1853/78685
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Energy harvesting using galvanic cells in the gastrointestinal (GI) tract can provide supplementary power and prolong the service life of ingestible devices. This work explores the impact of electrode type, dimension, and varying GI conditions on the performance of galvanic cells for powering ingestible devices. In vitro experiments were conducted with varying cathode and anode combinations in synthetic gastric fluid (SGF) under a load resistance sweep to measure the voltage of the galvanic cell. 23 tests assessed the peak power, energy capacity, and longevity of each electrode pair. Galvanic cell performance was also evaluated under simulated GI conditions, (including varying pH, salt concentration, added foreign substances, and simulated intestinal conditions), varying electrode dimensions, and varying set load resistances. Platinum (Pt) and palladium (Pd) cathodes showed the highest peak power and energy capacity, while molybdenum (Mo) was cost-effective for transient electronics applications. Magnesium (Mg) was optimal for short-term use, while zinc (Zn), the AZ31B Mg alloy, or the Zn-Mg 'hybrid' were preferred for long-term applications. Energy generation decreased with increasing pH but improved with higher salt concentration. Large particulate matter in gastric fluid hindered performance, and energy generation in intestinal fluids was less efficient. Larger cathode-to-anode size ratios increased efficiency, while larger anodes provided greater longevity. Efficiency was observed to be highest for Pt-Zn and Pt-AZ31 when the internal resistance was equal to the load resistance, but was higher for Pt-Mg as the load resistance increased. This study successfully characterized the effects of electrode combinations, GI conditions, and dimensions on the performance of galvanic cells, offering insight into the design of supplementary power sources for ingestible devices. These findings aid the development of galvanic cells for short-term and long-term applications in ingestible devices.
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2025-07-23
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