Session: 10-01 Hydrogen Energy, Alternative Fuels, Bioenergy, and Biofuels

Paper Number: 106683

106683 - Control of Bubble Dynamics for Enhancing Performance of Hydrogen Electrolyzers 

US Department of Energy is targeting an 80% reduction in the cost of green H₂ production by 2030. Currently, the top technology for producing green H₂ involves electrolysis, with the electricity supplied from wind/solar installations. In addition to the relatively high cost of renewables-based electricity, cost of electrolyzers is one of the biggest barriers to achieving DoE’s target. This study details avenues for reducing electrolyzer costs by enhancing electrolyzer H₂ yields (per unit size) dramatically by optimizing bubble dynamics associated with H2 generation. All H₂ produced in an electrolyzer starts as bubbles (nanoscale to millimeter scales); however indiscriminate bubble formation covers surface of catalyst layer, blocks ion conduction pathways and results in overpotentials, which reduce effectiveness and efficiency.

Key objective of this study is to maximize H₂ yield per unit surface area (or volume). In addition to electrochemical considerations, H₂ bubble dynamics depends on: i) bubble nucleation rate, ii) bubble growth rate, iii) bubble departure frequency and size. Each of these phenomena can be controlled by surface engineering (manipulation of surface texture and chemistry). Importantly, all surface engineering concepts need to be compatible with process electrochemistry.

This study details first principles-based analysis of various aspects of bubble dynamics to quantify potential increases in H2 yields of electrolyzers. This involves first principles-study of isolated, electrochemically generated bubbles, which is then expanded to account for bubble interactions. This analysis borrows concepts from the field of boiling heat transfer, where surface engineering has been successfully used to enhance heat transfer and delay the onset of the boiling crisis (surface starved of liquid). The vast body of knowledge about thermally-generated bubbles can be translated to electrochemically generated bubbles for H₂ production. Results of this analysis highlight the potential of pursuing surface engineering as an option for performance enhancement and cost reduction of H2 electrolyzers.

Presenting Author: Vaibhav Bahadur The University of Texas at Austin

Presenting Author Biography: Vaibhav Bahadur (VB) is an Associate Professor and Carl J. Eckhardt Fellow in Mechanical Engineering at UT Austin. His research interests are in the areas of thermal-fluids sciences, materials chemistry, machine learning and micro-nanofabrication. His group conducts fundamental and applied research in these areas with applications in energy-water systems, carbon capture and sequestration, hydrogen and thermal management.

Prof. Bahadur has a PhD in Mechanical Engineering from Purdue University and a Postdoc from Harvard University. Additionally, he has 4 years industry R&D experience in GE Global Research and Baker Hughes. Prof. Bahadur is the recipient of the NSF CAREER Award (2017), the SPE Petroleum Engineering Young Faculty Award (2015), the ASME ICNMM Outstanding Early Career Award (2018), the Google Faculty Research Award (2018), and the ACS Doctoral New Investigator Award (2014). He is the winner of the Society of Petroleum Engineer’s R&D Competition at SPE Annual Technical Conference and Exhibition (2014). Heat pipe technology developed in his lab was tested on the International Space Station in 2017.

Prof. Bahadur has authored 60 journal articles (h-index of 27), 35 articles in conference proceedings, 1 book chapter, and has 10 patents issued or pending. His research has been featured on the cover of ASME’s Mechanical Engineering magazine, cover of journals (ACS Nano, Advanced Optical Materials) and in R&D magazine. His research has been highlighted in multiple international news media. He teaches courses in the areas of heat transfer and fluid mechanics.