Collaborated with Prof. Pei Dong and her student, Boshen Xu, from George Mason University, we recently have one review paper titled with “Surface Reconstruction of Versatile Perovskites via In Situ Nanoparticle Engineering for Solid Oxide Cells” to be published by Chem Catalysis.
Dr. Jiufeng Ruan, our postdoc researcher, is the equal first author together with Boshen.
This review discusses the atomic-scale surface reconstruction of perovskite oxides via in situ exsolution. It emphasizes the fundamental mechanisms, strategies for precise process control, and the recent progresses of advanced techniques for in situ explorative characterizations. These insights provide guidance for designing durable and efficient perovskite catalysts in solid oxide cells.
Congratulations, everyone! The paper link will be provided soon.
Hybridizing Electrode Interface Structures in Protonic Ceramic Cells for Durable, Reversible Hydrogen and Power Generation
Protonic ceramic electrochemical cells (PCECs) represent a transformative sustainable technology for hydrogen production and power generation, offering an efficient means of energy cycling between electrical and chemical forms. Operating at intermediate temperatures, PCECs utilize proton-conducting ceramic electrolytes, achieving high efficiency, reduced material degradation, and seamless integration with renewable energy systems. These advantages position PCECs as a key component of future sustainable energy solutions. However, a significant challenge remains at the oxygen electrode, where sluggish reaction kinetics and limited active sites hinder overall performance. To address these limitations, we present a hybrid oxygen electrode featuring a PrNi0.7Co0.3O3–δ (PNC) backbone infused with oxygen vacancy-rich praseodymium oxide (PrOx) nanoparticles. This design leverages the interplay between surface and bulk properties to enhance oxygen adsorption, diffusion, and catalytic kinetics. The PrOx nanoparticles introduce abundant oxygen vacancies and modulate the d-band center for optimal adsorption energy, while the PNC backbone provides robust proton conduction and stabilizes reaction intermediates. Electrochemical full cells incorporating this hybrid electrode demonstrate a peak power density of 1.56 W cm-2 at 600°C in fuel cell mode and a current density of 2.25 A cm-2 at 1.30 V in electrolysis mode. Faradaic and energy efficiencies reach 96.8% and 89.9%, respectively, with exceptional thermal cycling stability and reduced polarization resistance (0.079 Ω cm2). By integrating oxygen vacancy engineering with proton-conducting frameworks, this study highlights a scalable approach to overcoming fundamental limitations in PCEC design. The results underscore the potential of advanced electrode architectures to significantly enhance the efficiency, durability, and applicability of PCECs in renewable energy systems.
The growing demand for clean energy and the urgent need to reduce carbon emissions have accelerated the development of alternative energy solutions, with solid oxide electrochemical cells standing out due to their efficiency in energy conversion between renewable energies and hydrogen. However, slow reaction kinetics of its oxygen electrode, particularly at intermediate temperatures, imposes a significant obstacle to optimizing their performance, reversibility, and durability. To address these challenges, this study introduces a new A-site deficient perovskite oxide as a potential electrode material for reversible protonic ceramic electrochemical cells. The cation deficiency could effectively trigger the formation of oxygen vacancies and proton defects after hydration to facilitate multiple charge carrier conduction for enhancing electrode activity. By investigating the effects of cationic deficiency in praseodymium nickel cobaltite perovskite (Pr1-xNi0.7Co0.3O3-) on structure and electrode polarization in symmetric cell configuration, the optimal composition is confirmed and used for integrating into full cells. The electrochemical performances in both fuel cell and electrolysis modes were studied and the reversible operation and short-term stability were carried out to understand the improved behaviors, providing the pathway of creating excessive proton conductivity for enhancing reaction activity on oxygen electrode.
With the material system operating at lower temperatures, protonic ceramic electrochemical cells (PCECs) can offer high energy efficiency and reliable performance for both power generation and hydrogen production, making them a promising technology for reversible energy cycling. However, PCEC faces technical challenges, particularly regarding electrode activity and durability under high current density operations. To address these challenges, we present a scalable nano-architecture ultra-porous oxygen electrode with triple conductivity, designed to enhance catalytic activity and interfacial stability through a self-assembly approach. Electrochemical cells incorporating this advanced electrode have demonstrated robust performance, achieving a peak power density of 1.50 W cm⁻2 at 600 °C in fuel cell mode and a current density of 5.04 A cm-2 at 1.60 V in electrolysis mode, with enhanced stability on transient operations and thermal cycles. The underlying mechanisms are closely related to the improved surface activity and mass transfer due to the dual features of the electrode structure. Additionally, the enhanced interfacial bonding between the oxygen electrode and electrolyte contributes to increased durability and thermomechanical integrity. This study underscores the critical importance of optimizing electrode microstructure to achieve a balance between surface activity and durability.
The emerging applications of steam electrolysis and electrochemical synthesis at 300-600 oC set stringent requirements on the stability of protonic ceramic cells, which cannot be met by Ce-rich electrolytes. A promising candidate is Ce-free BaZr0.8Y0.2O3−δ (BZY), yet its usage has long been denied due to sinterability conundrum in protonic devices. Here we resolved the issue by a renovated co-sintering process, in which the shrinkage stress of a readily sinterable support layer helps densify pure BZY electrolyte membrane at record low temperatures. It eliminates Ce and harmful sintering aids in zirconate cells and enhances Faraday efficiency and electrochemical stability, especially under harsh operation conditions. The protonic zirconate cells have exceptional performance and demonstrate stable high-steam-pressure electrolysis up to 0.7 atm steam pressure, −2 A cm−2 current density, and over 800 hours of dynamic operation at 600 oC. Our processing breakthrough enables stabilized protonic cells in demanding applications in future energy infrastructure.
This work was completed by multiple institutions including Idaho National Laboratory, New Mexico State, OU, Georgia Tech, Tsinghua University, and MIT.
Reducing the energy and carbon intensity of the conventional chemical processing industry can be achieved by electrochemically transforming natural gases into higher-value chemicals with higher efficiency and near-zero emissions.
In this work, the direct conversion of methane to aromatics and electricity has been achieved in a protonic ceramic electrocatalytic membrane reactor through the integration of a proton-conducting membrane assembly and a trimetallic Pt–Cu/Mo/ZSM-5 catalyst for the nonoxidative methane dehydro-aromatization reaction. In this integrated system, a remarkable 15.6% single-pass methane conversion with an 11.4% benzene yield has been demonstrated, while a peak power density of 276 mW cm–2 is obtained at 700 °C. The enhanced 15.7% increase in conversion and 16.0% improvement in the yield are observed when compared with the thermochemical process, which is attributed to the shift of reaction equilibrium by the removal of hydrogen through the protonic membrane. Concurrently, the faster H2 removal at a higher electrical current gave rise to a higher methane conversion and benzene yield. Furthermore, the catalyst can be efficiently regenerated by eliminating carbon deposition. A stable cell potential is maintained for 45 h under a constant current load of 0.13 A cm–2. The dual production of aromatics and electricity in the electrocatalytic membrane reactor has been demonstrated to be an attractive approach for decarbonizing chemical processing.
Our new PhD students Anshu and Yuqi are joining us to pursue exciting research on energy conversion and storage. They will focus on developing advanced energy materials for solid oxide cells to achieve high-efficient and durable power generation and hydrogen production.
We recently published a paper in Nature Communications entitled with “Direct conversion of methane to aromatics and hydrogen via a heterogeneous trimetallic synergistic catalyst“. In this work, a new catalyst was developed to improve non-oxidative methane dehydrogenase-aromatization reaction kinetics for more efficiency methane conversion to aromatics with high selectivity. We worked together with George Mason University, Idaho National Laboratory, and Kansas State University to deliver this fantastic paper. If you are interested, please download to read via this link:
On March 13, 2024, the U.S. Department of Energy (DOE) announced the selection of our project “Development of Readily Manufactured and Interface Engineered Proton-Conducting Solid Oxide Electrolysis Cells with High Efficiency and Durability” for funding with $3.1 million, which will focus on interface engineering and optimization to improve proton-conducting solid oxide electrolyzer performance and durability. This effort builds off recent successful interfacial optimization work and incorporates additional activities focused on high-efficiency and long lifetime stacks designed for scalable manufacturing. We will work with Dr. Bilge Yildiz at Massachusetts Institute of Technology (MIT), Dr. Chuancheng Duan at Kansas State University, and Chemtronergy LLC in Salt Lake City, to deliver the efficient and durable high-temperature electrolysis technology.
This announcement represents the first phase of implementation of two provisions of the Bipartisan Infrastructure Law, which authorizes $1 billion for research, development, demonstration, and deployment (RDD&D) activities to reduce the cost of clean hydrogen produced via electrolysis and $500 million for research, development, and demonstration (RD&D) of improved processes and technologies for manufacturing and recycling clean hydrogen systems and materials. These projects will directly produce more than 1,500 new jobs, along with thousands of additional jobs indirectly generated through regional economic activity. Additionally, these projects will provide support to 32 disadvantaged communities.
Together with the Regional Clean Hydrogen Hubs (H2Hubs), tax incentives in the President’s historic Inflation Reduction Act, and ongoing research, development, and demonstration in the DOE Hydrogen Program, these investments will help DOE achieve its ambitious Hydrogen Shotgoal of reducing the cost of producing clean hydrogen to $1 per kilogram. These projects will also support the long-term viability of the H2Hubs and other emerging commercial-scale deployments by helping to solve the underlying technical barriers to cost reduction that can’t be overcome by scale alone.
For more details, please refer to this link: https://www.energy.gov/eere/fuelcells/bipartisan-infrastructure-law-clean-hydrogen-electrolysis-manufacturing-and-0
