Two U-M Mechanical Engineering PhD students were awarded 2025-26 Rackham Predoctoral Fellowships
Each year, the University of Michigan Rackham Graduate School awards at least 85 Rackham Predoctoral Fellowships to doctoral candidates at U-M. Approximately 240 students are nominated for these fellowships each year, representing PhD programs from across the University.
Fellowship awardees are doctoral students who have achieved candidacy and are actively working on dissertation research and writing. The Fellowship seeks to support students working on dissertations that are unusually creative, ambitious, and impactful. Recipients are selected based on a number of factors, including the quality of their research and excellence in graduate teaching, pedagogy, mentoring, or professional leadership and service.
This year, two Mechanical Engineering PhD students were named recipients of Rackham Predoctoral Fellowships! Congratulations!
Rachel Silcox
During my PhD, my work develops and validates a novel electrochemical method for carbon dioxide (CO2) removal from ocean water, while functioning as energy storage. By leveraging ocean water, a key CO2 sink affected by ocean acidification, my researched method has the potential to operate continuously despite renewable energy intermittency. Using a cyclic pH-swing process with proton-coupled reactions, I minimize energy use and cost through modeling and testing a lab scale reactor. I optimize the reactor’s performance to enhance mass transport and reduce costs via design and operational parameters.
My results indicate improvements in fouling management, cost savings, and integration with renewable energy systems. I seek to address scale-up challenges by interviewing industry experts and exploring uses for the extracted CO2, such as converting it to methanol. This comprehensive approach combines modeling, lab experiments, and a scalability analysis to accelerate the uptake of carbon removal technologies and safeguard the environment from the impacts from climate change.
I’m honored to receive this fellowship and I am excited to use it to shine a light on the investments of time and funding needed to scale renewable energy technologies today. Scaling these technologies is the critical missing step to ensure the competitiveness of renewable technologies in the market tomorrow.
Advised by Rohini Bala Chandran.
Archie Yao
The effort to electrify transportation is currently supported by lithium-ion (Li-ion)batteries. However, further electrification of transportation and other major economic sectors demands batteries with higher energy density and improved safety. As a promising post-Li-ion battery energy storage solution, all-solid-state batteries (ASSBs) offer benefits by alleviating safety concerns by replacing the flammable liquid electrolyte with nonflammable solid electrolytes and have the potential to increase the energy density when pairing the lithium-metal anode with high-energy-density cathodes.
Despite the achievements so far, ASSBs still face various challenges including, but not limited to, Li-ion transportation and interfacial contact. Collaborating with characterization and experimental teams, my research has focused on identifying critical phenomena in ASSBs and determining the relevant physical mechanisms that dominate the phenomenon.
On the cathode side of ASSBs I resolved a long-standing problem of open-circuit voltage models in literature violating the second law of thermodynamics, and proposed one that is second-law-consistent. Additionally, I pointed out the limitation of effective medium theory for tortuosity modeling in ASSB cathodes and modeled cathode tortuosity using flux-based simulation. For anode-separator interface, a contact area model was developed consistent with the Mullins-Sekerka approach. Integrating these contributions, I constructed a pseudo-2D model for ASSBs, which provided a roadmap for achieving 350 Wh/kg specific energy at practical discharge rates and thus enabled real-world application of ASSBs.
Advised by Venkat Viswanathan.Â