About

Regina García-Méndez is an Assistant Professor in the Department of Materials Science and Engineering at Johns Hopkins University, having joined the institution in September 2023. Her research program focuses on advanced materials characterization, materials chemistry, and materials processing science, with the goal of understanding materials' behavior through multi-scale characterization to address energy and environmental challenges. She aims to develop scalable energy storage and electrocatalysis technologies for producing renewable fuels, drawing inspiration from a multidisciplinary approach that includes materials science, chemical engineering, mechanical engineering, and chemistry. García-Méndez specializes in synthesizing and functionalizing inorganic materials in the solid state and leverages various advanced characterization tools such as X-ray and neutron scattering, electron and scanning probe microscopy, and molecular and chemical analysis techniques to unravel the mysteries of materials at multiple scales. Her academic background includes a bachelor’s in chemical engineering from UVG in Guatemala, a master’s in materials science and engineering from Michigan State University, and a PhD in Materials Science and Engineering from the University of Michigan. She also completed a post-doctoral research fellowship at Cornell University, where she focused on materials and interphase design for highly reversible, long-duration, cost-effective aluminum batteries. García-Méndez has been recognized with several awards, including a Fulbright fellowship, a community engagement award from the Society of Hispanic Professional Engineers, and a postdoctoral fellowship from the Cornell Energy Systems Institute. She currently serves as Chair of the Early Career Researcher Board for Oxford Open Energy and as an Associate Editor for the Journal of the American Ceramic Society. Her vision extends to training the next generation of engineers and scientists to develop low-carbon energy solutions, and her research group is dedicated to pushing the boundaries of knowledge to shape a sustainable and cleaner energy future.

Research topics

• Materials science
• Chemical engineering
• Nanotechnology
• Inorganic chemistry
• Composite material

Selected publications

• AI agents for solid electrolytes: opportunities, challenges, and future directions

  AI Agent · 2025-12-31 · 3 citations

  articleOpen access

  Artificial intelligence (AI) and autonomous agents are transforming the discovery and optimization of solid electrolytes, a class of materials crucial to the safety and performance of next-generation batteries. This review summarizes recent progress in integrating machine learning, molecular dynamics, and density functional theory within closed-loop or semi-autonomous workflows that accelerate the evaluation of ionic conductivity, electrochemical and chemical stability, and processability. Data-driven frameworks now accelerate the screening of sulfides, oxides, and halides, while phase-field and multiscale models have provided mechanistic insight into dendrite formation, interfacial degradation, and chemo-mechanical coupling. Autonomous laboratories that combine robotic synthesis, in situ characterization, and Bayesian optimization further enable closed-loop experimental discovery. Despite this progress, challenges remain in data quality, model interpretability, and the limited autonomy of current systems. Future development will rely on five key directions: (1) constructing interoperable multiscale databases, (2) developing explainable and data-efficient algorithms, (3) tightly integrating computation with experiment, (4) exploring new solid-electrolyte chemistries via agent-driven optimization, and (5) fostering coordinated global collaboration among open AI agents. Together, these developments mark a transition from empirical discovery to an integrated, self-improving research paradigm, where AI evolves from a predictive assistant into an active collaborator that learns, reasons, and supports materials innovation alongside human researchers.

  PublisherDOI

• Engineering stable interphases with multi-salt electrolytes

  Joule · 2025-03-01 · 1 citations

  article1st authorCorresponding
  PublisherDOI

• Solid-state polymer-particle hybrid electrolytes: Structure and electrochemical properties

  Science Advances · 2024-07-05 · 40 citations

  articleOpen access

  Solid-state electrolytes (SSEs) are challenged by complex interfacial chemistry and poor ion transport through the interfaces they form with battery electrodes. Here, we investigate a class of SSE composed of micrometer-sized lithium oxide (Li 2 O) particles dispersed in a polymerizable 1,3-dioxolane (DOL) liquid. Ring-opening polymerization (ROP) of the DOL by Lewis acid salts inside a battery cell produces polymer-inorganic hybrid electrolytes with gradient properties on both the particle and battery cell length scales. These electrolytes sustain stable charge-discharge behavior in Li||NCM811 and anode-free Cu||NCM811 electrochemical cells. On the particle length scale, Li 2 O retards ROP, facilitating efficient ion transport in a fluid-like region near the particle surface. On battery cell length scales, gravity-assisted settling creates physical and electrochemical gradients in the hybrid electrolytes. By means of electrochemical and spectroscopic analyses, we find that Li 2 O particles participate in a reversible redox reaction that increases the effective CE in anode-free cells to values approaching 100%, enhancing battery cycle life.

  PublisherOA PDFDOI

• Recent progress and challenges for manufacturing and operating solid-state batteries for electric vehicles

  MRS Bulletin · 2024-06-11 · 14 citations

  articleSenior author
  PublisherDOI

• WITHDRAWN

  ChemRxiv · 2024-03-11 · 1 citations

  preprintOpen access

  This content was removed at the authors' request due to an error in the submission information. A corrected version is now available: 10.26434/chemrxiv-2024-d0j6v-v2

  PublisherOA PDFDOI

• Mechanistic Understanding of Long Duration Fast Charge Aqueous Zinc Batteries Using Physically Adsorbed Oligomers as Interphases

  ACS Applied Materials & Interfaces · 2024-10-30 · 2 citations

  article

  Polymers have been used as additives in the liquid electrolytes typically used for secondary batteries that utilize metals as anode. Such additives are conventionally argued to improve long-term anode performance by suppressing morphological and hydrodynamic instabilities thought to be responsible for out-of-plane and dendritic metal deposition during battery charging. More recent studies have reported that the polymer additives provide even more fundamental mechanisms for stabilizing metal electrodeposition through their ability to regulate metal electrodeposit crystallography and, thereby, morphology. Few studies explore how polymers carried in a liquid electrolyte achieve these functions, and fewer still provide rules for choosing among the various polymer types, the additive polymer molecular weight (Mw), and concentration in the electrolyte. Here, we investigate how these generally easy-to-control variables influence electrochemical interphase formation inside battery cells and their impact on the morphology and reversibility of Zn electrodes in aqueous electrolytes. We focus on aqueous Zn-iodine electrochemical cells containing linear polyethylene glycol (PEG) chains as additives and find that in electrolytes where the polymer concentration is maintained in the dilute solution regime there is an optimum polymer molecular weight (Mw ≈ 1000 Da), above which beneficial effects of polymers on Zn electrode reversibility and Zn–I2 battery lifetime are progressively lost. By means of optical ellipsometry and theoretical calculations, we show that the optimal Mw is associated with saturation of the thickness of a physiosorbed PEG coating on the Zn metal electrode. Electron microscopy and X-ray photoelectron spectroscopy analysis of Zn electrodeposits formed in such electrolytes reveal that the physiosorbed polymer coating has two primary effects─it regulates the deposit morphology and suppresses parasitic reactions between the electrode and electrolyte components. The parasitic reactions produce species like ZnO, which are known to passivate the Zn electrode and promote nonuniform deposition. Galvanostatic cycling measurements in aqueous Zn–I2 cells containing the PEG additives at the optimal Mw show that the cells maintain very high Coulombic efficiencies (≥99%) at current densities as high as 50 mA/cm2─close to the maximum values permissible across the Celgard separator membranes used in our studies.

  PublisherDOI

• Correlation between mechanical properties and ionic conductivity of polycrystalline sodium superionic conductors: A relative density-dominant relationship

  Materials Today Energy · 2024-07-04 · 26 citations

  articleOpen access

  Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their correlation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summarizes recent literature on the sintered polycrystalline NASICON solid electrolyte Na1+xZr2SixP3-xO12 (NZSP, 0≤x ≤ 3), focusing on its mechanical properties and ionic conductivity, and identifies a positive correlation between these properties at ambient temperatures. Microstructural analysis reveals that a range of factors, including relative density, grain size, secondary phases, and crystal structures significantly influence the properties of NZSP. Notably, an increase in relative density uniquely contributes to simultaneous enhancements in both hardness and ionic conductivity. Consequently, future research should prioritize enhancing the relative density of NZSP, potentially by employing advanced sintering techniques such as spark plasma sintering (SPS) and microwave-assisted sintering. The correlation between mechanical properties and ionic conductivity observed in NZSP is also evident in other oxide solid electrolytes, such as garnet Li7La3Zr2O12 (LLZO). This investigation not only suggests a potential linkage between these crucial properties but also guides subsequent strategies for refining polycrystalline oxide solid electrolytes for advanced battery technologies.

  PublisherDOI

• Li-stuffed garnet solid electrolytes: Current status, challenges, and perspectives for practical Li-metal batteries

  Energy storage materials · 2024-12-20 · 23 citations

  articleOpen access

  Solid-state Li-metal batteries have gained considerable attention for next-generation energy storage because of their potential high energy densities and improved safety. Solid electrolytes are critical to the development of solid-state Li-metal batteries. While various solid electrolytes exhibit fast-ion conductivity, garnet-type oxides are among the few that show good chemical stability against Li metal. In addition, their high oxidation stability allows the use of high-voltage cathodes. However, the practical application of garnet solid electrolytes faces severe challenges: 1) difficulty in sintering thin and large-area garnet solid electrolytes, 2) large interfacial resistance between garnet electrolytes and electrode materials, and 3) Li dendrite growth. This review summarizes recent advances in garnet-type solid electrolytes and emphasizes the key challenges hindering their practical application in Li-metal batteries. Based on a comprehensive literature survey and our studies, the optimization of crystal structure and ionic conductivity in Li 7 La 3 Zr 2 O 12 (LLZO) is nearly complete. The focus of the field is shifting from high-temperature sintered thick pellets to low-temperature processed thin and flexible LLZO-based organic/inorganic sheet electrolytes, which are more promising for commercialization. Additional research is needed to fully understand the mechanics, interface behavior, Li-ion pathway, and manufacturability of castable LLZO-based sheet electrolytes. In terms of cell energy density, the gravimetric energy density of polycrystalline LLZO-based all-solid-state Li-metal pouch cells is estimated to reach only 272 Wh kg -1 under ideal conditions.

  PublisherDOI

• Correlation between mechanical properties and ionic conductivity of sodium superionic conductors: a relative density-dependent relationship

  ChemRxiv · 2024-03-12 · 1 citations

  preprintOpen access

  Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their interrelation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summarizes recent literature on NASICON solid electrolytes Na1+xZr2SixP3-xO12 (NZSP, 0≤x≤3), highlighting the mechanical properties and ionic conductivity, and identifies a positive correlation between mechanical strength, in particular hardness, and ionic conductivity at ambient temperatures. Microstructural analysis reveals that a range of factors, including relative density, grain size, secondary phases, and crystallographic structures, significantly influence material properties. Notably, an increase in relative density uniquely contributes to simultaneous enhancements in both ionic conductivity and mechanical strength. Consequently, future research should prioritize enhancing the relative density of NASICON solid electrolytes, possibly employing advanced techniques, including sol-gel process, spark plasma sintering (SPS), and microwave-assisted sintering. The correlation between mechanical properties and ionic conductivity observed in NASICON solid electrolytes extends to other high-temperature sintered oxide electrolytes like Li7La3Zr2O12 (LLZO). This investigation not only suggests a potential linkage between these crucial properties but also guides subsequent strategies for refining solid electrolytes for advanced battery technologies.

  PublisherOA PDFDOI

• Correlation between mechanical properties and ionic conductivity of sodium superionic conductors: a relative density-dominant relationship

  ChemRxiv · 2024-06-24 · 1 citations

  preprintOpen access

  Sodium superionic conductors (NASICON) are pivotal for the functionality and safety of solid-state sodium batteries. Their mechanical properties and ionic conductivity are key performance metrics, yet their correlation remains inadequately understood. Addressing this gap is vital for concurrent enhancements in both properties. This study summarizes recent literature on the sintered polycrystalline NASICON solid electrolyte Na1+xZr2SixP3-xO12 (NZSP, 0≤x≤3), focusing on its mechanical properties and ionic conductivity, and identifies a positive correlation between these properties at ambient temperatures. Microstructural analysis reveals that a range of factors, including relative density, grain size, secondary phases, and crystal structures, significantly influence the properties of NZSP. Notably, an increase in relative density uniquely contributes to simultaneous enhancements in both hardness and ionic conductivity. Consequently, future research should prioritize enhancing the relative density of NZSP, potentially by employing advanced sintering techniques such as spark plasma sintering (SPS) and microwave-assisted sintering. The correlation between mechanical properties and ionic conductivity observed in NZSP is also evident in other oxide solid electrolytes, such as garnet Li7La3Zr2O12 (LLZO). This investigation not only suggests a potential linkage between these crucial properties but also guides subsequent strategies for refining polycrystalline oxide solid electrolytes for advanced battery technologies.

  PublisherOA PDFDOI

Frequent coauthors

• Jeff Sakamoto

  University of Michigan–Ann Arbor

  22 shared

• Jingxu Zheng

  The University of Texas at Austin

  14 shared

• Lynden A. Archer

  Cornell University

  13 shared

• Eric Kazyak

  University of Wisconsin–Madison

  12 shared

• Kenneth J. Takeuchi

  Stony Brook University

  8 shared

• Esther S. Takeuchi

  Stony Brook University

  8 shared

• Amy C. Marschilok

  Brookhaven National Laboratory

  8 shared

• Yue Deng

  Cornell University

  7 shared

Awards & honors

• Fulbright fellowship for her master’s studies
• community engagement award from the Society of Hispanic Prof…