IMG_3174 2.HEIC
Josh Zak
NSF Graduate Research Fellow
About Me


I am an electrochemist and materials characterization expert with 5+ years of experience in Li-ion battery research. But how did I get here?

My introduction to research came in middle school when my family moved to the small beachside neighborhood of Glenelg outside of Adelaide, the capital of South Australia. My school there took us on a week-long trip to an environmental field station on Kangaroo Island where we spent a week catching and tagging marron (a species of small crayfish) in ponds, measuring the effect of the intensity of the sun on the behavior of different species of endemic ants, and searching for echidnas in the bush. Continuing the Australian theme to my education back in the States, my high school chemistry teacher, who happened to be Australian, transformed my developing scientific curiosity into a passion. I was immediately fascinated by the way chemistry takes the fundamental properties of matter and applies those principles to solve real-world problems.

As an undergraduate at Carnegie Mellon, I studied chemistry and worked with Prof. Stefan Bernhard to synthesize and characterize the photophysics of a series of fluorinated iridium complexes with strong potential in photocatalytic applications. I also studied materials science, leading me to a NSF-funded REU at the University of Puerto Rico, Mayagüez studying reconfigurable and soft materials. My intersectional interests in chemistry and materials engineering (along with a short course in energy storage materials) drove me to join the group of Prof. Kimberly See upon matriculating to Caltech for my doctorate work. At Caltech, I marry chemistry and materials science by focusing on uncovering the fundamental structure-property relationships that dictate performance and reversibility in Li-rich cathode materials for next-generation batteries.

Outside the lab, I enjoy hiking, concerts and music festivals, and advocating for LGBTQ+ representation and support in STEM.

Curriculum Vitae​




2017 - present, California Institute of Technology, Pasadena, CA

Doctor of Philosophy, Chemistry; Cumulative GPA: 3.85/4.00

Thesis: Complex Charge Compensation Mechanisms in Lithium-Rich Chalcogenide Cathodes

Advisor: Prof. Kimberly A. See

2013 - 2017, Carnegie Mellon University, Pittsburgh, PA

Bachelor of Science, Chemistry; Cumulative GPA: 3.80/4.00

Science and Humanities Scholar

Concentration: Materials Chemistry

Minor: Japanese Studies (Language and Culture)

Research Experience

2017 - present, California Institute of Technology, Pasadena, CA

Division of Chemistry and Chemical Engineering

Graduate Research Assistant, lab of Prof. Kimberly A. See

  • Determined charge compensation mechanisms in high-capacity Li-rich sulfide materials, successfully leading efforts to find definitive spectroscopic evidence of reversible anionic contributions to redox

  • Controlled effects of metal-anion covalency and determined local structure response to anion oxidation in a series of Li-rich chalcogenide cathodes to uncover relationships to reversibility and performance

  • Initiated development of in-house operando Raman spectroscopy capabilities and investigated local structural consequences of a dynamically changing redox mechanism in a mixed metal Li-rich oxide

  • Contributed spectroscopic and electrochemical expertise to cross-cutting efforts within the SCALAR DOE Energy Frontiers Research Center in collaboration with groups from 5 other institutions

2014 - 2017, California Institute of Technology, Pasadena, CA

Deparment of Chemistry

Undergraduate Research Assistant, lab of Prof. Stefan Bernhard

  • Led a project to synthesize photostable iridium metal complexes with long-lived excited states for use as catalysts for hydrogen evolution and other industrially relevant small molecule transformations

  • Awarded ACS Undergraduate Award in Inorganic Chemistry for excellence in inorganic coursework and research

Techniques and Skills

Electrochemistry: cyclic voltammetry, galvanostatic cycling, galvanostatic intermittent titration technique, electrochemical impedance spectroscopy

Materials Science: solid-state synthesis, X-ray diffraction, ex situ and operando synchrotron X-ray experiments (X-ray absorption spectroscopy, total scattering pair distribution function, hard X-ray photoelectron spectroscopy, resonant inelastic X-ray scattering), Raman spectroscopy, scanning electron microscopy

Computer: Demeter suite (XANES and EXAFS analysis), GSAS-II (XRD and PDF analysis), Biologic (EC-Lab) and MACCOR electrochemical testing software, LaTeX, Mathematica, Microsoft Office

Languages: English (native speaker), Japanese (conversational)

Publications (Google Scholar) *indicates co-first authorship

3. Martinolich, A. J.*; Zak, J. J.*; Kim, S. S.; Bashian, N. H.; Irshad, A.; Agyeman-Budu, D.; Narayan, S.; Melot, B. C.; Nelson Weker, J.; See, K. A. Controlling Covalency and Anion Redox Potentials through Anion Substitution in Li-rich Chalcogenides. Chem. Mater. 2021, 33, 378­–391. [doi]

2. Bashian, N. H.; Preefer, M. B.; Milam-Guerrero, J.; Zak, J. J.; Sendi, C.; Ahsan, S.; Vincent, R.; Haiges, R.; See, K. A.; Seshadri, R.; Melot, B. C. Understanding the Role of Crystallographic Shear on the Electrochemical Behavior of Niobium Oxyfluorides. J. Mater. Chem. A. 2020, 8, 12623. [doi]

1. Hansen, C. J.*; Zak, J. J.*; Martinolich, A. J.; Ko, J. S.; Bashian, N. H.; Kaboudvand, F.; Van der Ven, A.; Melot, B. C.; Nelson Weker, J.; See, K. A. Multielectron, Cation and Anion Redox in Lithium-Rich Iron Sulfide Cathodes. J. Am. Chem. Soc. 2020, 142, 6737­–6749. [doi]

Manuscripts in Preparation/Review

4. Zak, J. J.; Zuba, M.; Lebens-Higgins, Z. W.; Huang, H.; Crafton, M. J.; McCloskey, B. D.; Piper, L. F. J., See, K. A. Irreversible Anion Redox and Dynamically Changing Charge Compensation in Low-Ru Li-rich Cathode Li2Ru0.3Mn0.7O3. In preparation.

3. Zak, J. J.; Kim, S. S.; Laskowski, F. A. L.; See, K. A. From Intercalation to Conversion and the Hybrid Mechanisms Between: An Exploration of Sulfur Redox in Li Cathodes. In preparation.

2. Kim, S. S.; Agyeman-Budu, D. N.; Zak, J. J.; Dawson, A.; Yan, Q.; Cában-Acevedo, M.; Yao, Y.; Irshad, A.; Narayan, S. H.; Luo, J.; Nelson Weker, J.; Tolbert, S. H.; See, K. A. Promoting Reversibility of Multielectron Redox in Alkali-Rich Sulfide Cathodes through Cryomilling. In review, Jan 2022.

1. Wyckoff, K. E.; Kaufman, J. L.; Baek, S. W.; Dolle, C.; Zak, J. J.; Bienz, J.; Kautzch, L.; Vincent, R. C.; Zohar, A.; See, K. A.; Eggeler, Y. M.; Pilon, L.; Van der Ven, A.; Seshadri, R. Metal-Metal Bonding as an Electrode Design Principle in the Low-Strain Cluster Compound LiScMo3O8. In review, Nov 2021.

Selected Presentations

Oral, Materials Research Society, “Controlling Covalency and Anion Redox Potentials through Anion Substitution in Li-rich Chalcogenides.” 2021


Oral (invited), Queer Me Out LGBTQIA+ Short Talk Series (Caltech). 2020

Oral (invited), Stanford Synchrotron Radiation Lightsource Monthly Seminar, “Tunable Multielectron Redox in Lithium-Rich Iron Chalcogenide Cathodes.” 2020

OralGray-Hill Seminar (Caltech and Occidental College), "Building the Batteries of the Future: Tunable Multielectron Redox in Lithium-Rich Iron Chalcogenide Cathodes." 2020

Oral, Energy Frontiers Research Center Principal Investigator Meeting, “Investigating the Redox Activity and Lithiation of Boron Icosahedra in the Solid State.” 2019

Honors & Awards

Fellow, National Science Foundation Graduate Research Fellowship Program, 2019-present

Poster Award, Caltech Division of Chemistry and Chemical Engineering Seminar Day, 2019

Team Science Award, Office of Basic Energy Sciences, U.S. Department of Energy, 2018

Student Service Award, Carnegie Mellon Alumni Association, 2017 (highest university award for service)

Scholar, Andrew Carnegie Society, 2017 (given to 40 graduating seniors in a class of 1600)

Selected Community Involvement

Student Representative, Chemistry Graduate Studies Committee, Caltech, 2019-present

Founding Member & Junior Branch Advisor, CISV International, Southern California Chapter, 2019-present

Student Leader, PRISM/oSTEM, Caltech, 2018-present

Student Representative, LGBTQ+ Working Group, Caltech, 2018-present

Orientation Leader, Graduate Studies Office/Office of Residential Experience, Caltech, 2018, 2020, 2021