About

Chris Dames is the Chair of the Department of Mechanical Engineering at UC Berkeley and holds the Howard Penn Brown Chair in Mechanical Engineering. He received his Ph.D. in Mechanical Engineering from the Massachusetts Institute of Technology in 2006, and his B.S. and M.S. degrees from UC Berkeley in 1998 and 2001, respectively. Prior to joining UC Berkeley in 2011, he was a faculty member at UC Riverside from 2006 to 2011 and has also worked as a research engineer for Solo Energy Corp. His research emphasizes fundamental studies of heat transfer and energy conversion at the nanoscale, utilizing both theoretical and experimental methods. His interests include graphene, nanocrystalline materials, mean free path distributions, thermoelectrics, biological systems, and highly anisotropic and nonlinear transport phenomena such as thermal rectification. His work has been recognized with awards including a DARPA Young Faculty Award in 2009 and an NSF CAREER award in 2011.

Research topics

• Composite material
• Optics
• Optoelectronics
• Thermodynamics
• Materials science
• Physics
• Condensed matter physics

Selected publications

• A size-dependent ideal solution model for liquid–solid phase equilibria prediction in aqueous organic solutions

  Proceedings of the National Academy of Sciences · 2025-02-21 · 2 citations

  articleOpen access

  Predictive synthesis of aqueous organic solutions with desired liquid-solid phase equilibria could drive progress in industrial chemistry, cryopreservation, and beyond, but is limited by the predictive power of current solution thermodynamics models. In particular, few analytical models enable accurate liquidus and eutectic prediction based only on bulk thermodynamic properties of the pure components, requiring instead either direct measurement or costly simulation of solution properties. In this work, we demonstrate that a simple modification to the canonical ideal solution theory accounting for the entropic effects of dissimilar molecule sizes can transform its predictive power. Incorporating a Flory-style entropy of mixing term that includes both the mole and volume fractions of each component, we derive size-dependent equations for the ideal chemical potential and liquidus temperature, and use them to predict the binary phase diagrams of water and 10 organic solutes of varying sizes. We show that size-dependent prediction outperforms the ideal model in all cases, reducing average error in the predicted liquidus temperature by 59% (to 5.6 K), eutectic temperature by 45% (to 9.7 K), and eutectic composition by 43% (to 4.7 mol%), as compared to experimental data. Furthermore, by retaining the ideal assumption that the enthalpy of mixing is zero, we demonstrate that, for aqueous organic solutions, much of the deviation from ideality that is typically attributed to molecular interactions may in fact be explained by simple entropic size effects. These results suggest an underappreciated dominance of mixing entropy in these solutions, and provide a simple approach to predicting their phase equilibria.

  PublisherOA PDFDOI

• Domain-Wall Enhanced Pyroelectricity

  Physical Review X · 2025-03-18 · 7 citations

  articleOpen access

  Ferroelectric domain walls are not just static geometric boundaries between polarization domains; they are, in fact, dynamic and functional interfaces with the potential for diverse technological applications. While the roles of ferroelectric domain walls in dielectric and piezoelectric responses are better understood, their impact on pyroelectric response remains underexplored. Here, the pyroelectric response of (001)-, (101)-, and (111)-oriented epitaxial heterostructures of the tetragonal ferroelectric <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mrow><a:msub><a:mrow><a:mi>PbZr</a:mi></a:mrow><a:mrow><a:mn>0.2</a:mn></a:mrow></a:msub><a:msub><a:mrow><a:mi>Ti</a:mi></a:mrow><a:mrow><a:mn>0.8</a:mn></a:mrow></a:msub><a:msub><a:mrow><a:mi mathvariant="normal">O</a:mi></a:mrow><a:mrow><a:mn>3</a:mn></a:mrow></a:msub></a:mrow></a:math> is probed. These differently oriented heterostructures exhibit the same type of 90° ferroelastic domain walls, but their geometry and density vary with orientation. In turn, piezoresponse force microscopy and direct pyroelectric measurements reveal that (111)-oriented heterostructures exhibit both the highest density of domain walls and pyroelectric coefficients. By varying the thickness of these (111)-oriented heterostructures (from 100 to 280 nm), the density of domain walls can be varied, and a direct correlation between domain-wall density and pyroelectric coefficients is found. Molecular-dynamics simulations confirm these findings and reveal a novel domain-wall contribution to pyroelectric response in that the volume of the material in or near the domain walls exhibits a significantly higher pyroelectric coefficient as compared to the bulk of the domains. Analysis suggests that the domain-wall material has a higher responsivity of the polarization to both external fields and temperature. This study sheds light on the microscopic origin of domain-wall contributions to pyroelectricity and provides a pathway to controlling this effect.

  PublisherOA PDFDOI

• Solid-state batteries enabled by ultra-high-frequency self-heating

  Joule · 2025-06-10 · 6 citations

  articleOpen access
  PublisherOA PDFDOI

• Achieving Over 2000 Stable Cycles in Srcl₂/Graphene Composites for Building Thermal Energy Storage Via Optimized Synthesis Pathways

  SSRN Electronic Journal · 2025-01-01

  preprintOpen access
  PublisherDOI

• A needle-form 3-omega sensor for thermal conductivity measurements of soft materials and biological tissues

  Scientific Reports · 2025-11-28

  articleOpen accessSenior author

  Soft materials, liquids, and biological tissues are of increasing interest as thermal materials for applications in energy storage, electrical/electrochemical systems, and cryopreservation, but thermal characterization of these materials can be challenging experimentally. Here, we extend the robust 3-omega method, which is traditionally based on a planar form factor with external sample contact, to a microfabricated needle-form sensor that can be plunged directly into a sample. We further demonstrate the reusability of this sensor, the ability to easily make thermal contact by plunging the sensor into the center of a sample, and the ability to sample systems undergoing phase transformations. We do so via application to solid ice as well as 4 representative materials at room temperature: water, glycerol, paraffin, and chicken liver, thereby demonstrating the sensor's utility for liquids, soft solid materials, and phase change materials. Data analysis is conducted by fitting to a three dimensional numerical model of the sensor and sample. These experiments show very good agreement of within 3% of literature values for thermal conductivity for the explored materials, which range in thermal conductivity from approximately 0.3 W/mK to 2.3 W/mK.

  PublisherOA PDFDOI

• An Exact Closed-Form Solution for the 2ω Method for an Arbitrarily Anisotropic Substrate

  ASME Journal of Heat and Mass Transfer · 2025-06-23 · 1 citations

  articleSenior author

  Abstract The 2ω method, in which the temperature sensing line is separate from the heater line, and the closely related 3ω method, with a heater line that is its own temperature sensor, are popular electrothermal techniques for measuring the thermal conductivity. For the 2ω method, Ordonez-Miranda et al. (2023, “Analytical Integration of the Heater and Sensor 3ω Signals of Anisotropic Bulk Materials and Thin Films,” J. Appl. Phys., 133(20), p. 205104) recently obtained an analytical solution for its thermal model for a substrate with differing in-plane and out-of-plane thermal conductivities. Here, we further generalize the 2ω thermal model by deriving an exact closed-form solution for a substrate of arbitrarily aligned thermal conductivity. The derivation builds on a Green's function from Mishra et al. (2015, “A 3 Omega Method to Measure an Arbitrary Anisotropic Thermal Conductivity Tensor,” Rev. Sci. Instrum., 86(5), p. 054902), and the resulting 2ω expression is shown to maintain a similar Meijer G-function form as the known analytical solution of the 3ω method.

  PublisherDOI

• Thermal-EIS: Depth Resolved Thermo-Electrochemical Impedance Analysis of Lithium-Ion Batteries and Beyond

  ECS Meeting Abstracts · 2025-11-24

  article

  Motivation: To further advance battery energy density, safety, and longevity, it is crucial to develop more non-intrusive and operando diagnostic tools to understand battery kinetics and interfacial phenomena. The current state-of-the-art non-intrusive diagnostic method, electrochemical impedance spectroscopy (EIS), offers rich information on battery performance by decoupling contributions from bulk ion transport, interface resistances, kinetically controlled charge transfer, and ion diffusion. However, one of the key limitations of EIS is its lack of resolution in depth; for example, conventional EIS gives the total charge transfer resistance (Rct) but cannot distinguish the individual contributions from the anodic and cathodic sides. Similarly, separating the interface resistance from the solid electrolyte interface (SEI) versus the cathode electrolyte interface (CEI) could be challenging. To address this issue we are developing localized thermal metrologies to help provide some degree of depth-resolved information about a battery’s electrochemical impedance. Methodology and Approach: This work is built on the deep analogy between electrochemical and thermal transport, with their respective resistances of ionic/electrical conductivity vs. thermal conductivity, and capacitances from electrochemical vs. thermal energy storage properties. Here extending this analogy to EIS, the essence of thermal EIS is to apply a sinusoidal thermal forcing to a battery and observe the resulting thermal response, which then elucidates the internal electrochemical and thermal transport properties of the cell itself. Thermal EIS also offers one important advantage over traditional EIS, in that any thermal wave traveling into a solid remains relatively localized within a characteristic thermal penetration depth δ = α/ω , where α is thermal diffusivity and ω is angular frequency. This frequency-dependent localization enables depth-resolved studies: at higher frequencies (small δ), the response depends only on the properties of the near-surface battery layers, while lower frequencies (large δ) are sensitive to the properties of deeper regions as well. Lastly, the measured thermal responses could be linked to key electrochemical properties, such as internal heat generation due to poor interfacial contact. With frequency sweeping, this approach may help identify each interface's contribution to the total resistance in ion and thermal transport. Results : This talk will first introduce our recent work using these ideas for battery analysis, such as characterizing interface degradation in solid-state batteries [1], detecting lithiation in a graphite anode during fast charging [2], and developing Multi-harmonic ElectroThermal Spectroscopy (METS) [3] to infer depth-resolved heat generation during battery operation. We will then present ongoing thermal EIS work in solid-state batteries (Li | LAGP | Li and Li | LLZO | Li) using thermo-electrochemical coupled metrologies. We will further highlight how interface and charge transfer resistances evolve throughout cycling, demonstrating the potential of this approach to track degradation in real-time. Significance: Thermal EIS provides a valuable complement to traditional EIS by revealing depth-resolved information on the battery’s internal resistance and heat sources, thereby opening new doors for both commercial battery health monitoring and fundamental studies of next-generation battery chemistries. References [1] Chalise, D. et al . Using thermal interface resistance for noninvasive operando mapping of buried interfacial lithium morphology in solid-state batteries. ACS Appl. Mater. Interfaces (2023). https://doi.org/10.1021/acsami.2c23038 [2] Zeng, Y., Shen, F., Zhang, B. et al. Nonintrusive thermal-wave sensor for operando quantification of degradation in commercial batteries. Nat Commun (2023). https://doi.org/10.1038/s41467-023-43808-9 [3] Chalise, D. et al . Depth-resolved measurement of solvation entropy, interfacial transport and charge-transfer kinetics of practical lithium-ion batteries. arXiv (2024). https://arxiv.org/abs/2411.10920

  PublisherDOI

• What is Mechanical Engineering?

  Mechanical Engineering · 2024-07-29

  articleOpen access

  Abstract In a World of Diverse Challenges, Mechanical Engineers are Developing the Solutions. Their Contributions Have Never Been as Valuable As They are Today. “Almost everyone comes into contact with the products of mechanical engineering on a daily basis, but very few people—including some engineers themselves—can provide a succinct explanation of what mechanical engineering is. ”

  PublisherDOI

• A Size-Dependent Ideal Solution Model for Liquid-Solid Phase Equilibria Prediction in Aqueous Organic Solutions

  arXiv (Cornell University) · 2024-11-27

  preprintOpen access

  Predictive synthesis of aqueous organic solutions with desired liquid-solid phase equilibria could drive progress in industrial chemistry, cryopreservation, and beyond, but is limited by the predictive power of current solution thermodynamics models. In particular, few analytical models enable accurate liquidus and eutectic prediction based only on bulk thermodynamic properties of the pure components, requiring instead either direct measurement or costly simulation of solution properties. In this work, we demonstrate that a simple modification to the canonical ideal solution theory accounting for the entopic effects of dissimilar molecule sizes can transform its predictive power, while offering new insight into the thermodynamic nature of aqueous organic solutions. Incorporating a Flory-style entropy of mixing term that includes both the mole and volume fractions of each component, we derive size-dependent equations for the ideal chemical potential and liquidus temperature, and use them to predict the binary phase diagrams of water and 10 organic solutes of varying sizes. We show that size-dependent prediction outperforms the ideal model in all cases, reducing average error in the predicted liquidus temperature by 59\%, eutectic temperature by 45\%, and eutectic composition by 43\%, as compared to experimental data. Furthermore, by retaining the ideal assumption that the enthalpy of mixing is zero, we demonstrate that for aqueous organic solutions, much of the deviation from ideality that is typically attributed to molecular interactions may in fact be explained by simple entropic size effects. These results suggest an underappreciated dominance of mixing entropy in these solutions, and provide a simple approach to predicting their phase equilibria.

  PublisherOA PDFDOI

• Corner- and edge-mode enhancement of near-field radiative heat transfer

  Nature · 2024-04-17 · 24 citations

  articleSenior authorCorresponding
  PublisherDOI

Recent grants

• CAREER: Mean Free Path Spectroscopy - Experimental determination of the mean free path distribution in solids

  NSF · $287k · 2013–2016

• The 8th Japan-U.S. Joint Seminar on Nanoscale Transport Phenomena, July 13-16, 2014 in Santa Cruz, California

  NSF · $23k · 2014–2015

• GOALI: Nanoparticle Luminescence Thermometry with 10 nm Resolution for Challenging Environments

  NSF · $320k · 2015–2019

• Measuring the thermal conductivity of graphene

  NSF · $315k · 2009–2012

• CAREER: Mean Free Path Spectroscopy - Experimental determination of the mean free path distribution in solids

  NSF · $405k · 2011–2014

Frequent coauthors

• John C. Bischof

  University of Minnesota

  72 shared

• Harishankar Natesan

  Boston Scientific (United States)

  70 shared

• Junqiao Wu

  Lawrence Berkeley National Laboratory

  62 shared

• Xiang Zhang

  Shanghai Jiao Tong University

  53 shared

• Wyatt Hodges

  Sandia National Laboratories

  53 shared

• Ying Li

  Zhejiang University

  51 shared

• Cheng‐Wei Qiu

  National University of Singapore

  51 shared

• Asa H. Barber

  City, University of London

  49 shared

Education

• Ph.D., Mechanical Engineering

  University of California, Berkeley

  2000

• M.S., Mechanical Engineering

  University of California, Berkeley

  1996

• B.S., Mechanical Engineering

  University of California, Berkeley

  1994

Awards & honors

• DARPA Young Faculty Award (2009)
• NSF CAREER award (2011)