About

Bryan D. McCloskey is the Chair of Chemical and Biomolecular Engineering and the Warren and Katharine Schlinger Distinguished Professor in Chemical Engineering at the University of California, Berkeley. His research focuses on electrochemical energy storage, electrocatalysis, and molecular and ionic transport through polymers. His laboratory investigates fundamental processes occurring in electrochemical systems, with particular emphasis on batteries and electrocatalysis. McCloskey's work aims to address material challenges that limit the rechargeability and rate capability of high-energy battery chemistries such as lithium/oxygen and lithium/sulfur, with the goal of advancing practical energy storage solutions. He employs state-of-the-art techniques to characterize electrochemistry at multi-phase interfaces, providing insights for the development of improved energy storage, electrocatalysis, and corrosion-resistant materials. His contributions have significantly advanced understanding in these areas, and he has received numerous awards and honors for his research, including the NSF CAREER Award, the Charles W. Tobias Young Investigator Award, and the Tajima Prize.

Research topics

• Materials science
• Computer Science
• Chemistry
• Engineering
• Physics
• Chemical engineering
• Nanotechnology
• Physical chemistry
• Paleontology
• Engineering physics
• Library science
• Archaeology
• Organic chemistry
• Geography
• Psychology
• Geology
• Chemical physics
• Composite material
• Inorganic chemistry
• Nuclear physics
• Metallurgy
• Process engineering
• Thermodynamics

Selected publications

• WITHDRAWN

  ChemRxiv · 2026-03-05

  articleOpen accessSenior author

  Withdrawn because the content was an unintentional duplication of another ChemRxiv preprint (10.26434/chemrxiv.15000655/v1).

  PublisherDOI

• Tracing proton-lithium exchange and coincident surface contaminant decomposition upon heating of Li + -conductive garnet phase powders

  ChemRxiv · 2026-03-05

  articleOpen accessSenior author

  Garnet-phase Li7La3Zr2O12 (LLZO) is a promising solid-state electrolyte in lithium metal batteries, but suffers from contaminant formation upon exposure to ambient conditions. This work quantifies the impurities present in commercially synthesized and procured LLZO powder and characterizes the removal of these contaminants via heat treatment under argon. We identify 3 unique contaminant removal regimes, one of LiOH at lower temperatures (<350 ˚C) and two of Li2CO3 at intermediate (350-550 ˚C) and high (>550 ˚C) temperatures. Removal of LiOH and the intermediate Li2CO3 proceed through a mechanism involving beneficial H + /Li + exchange with the LLZO lattice, whereas high temperature Li2CO3 removal proceeds through the thermal decomposition mechanism of Li2CO3 to evolve CO2 and deposit solid Li2O. Heating to 800 ˚C allows for the removal of 97% of the Li2CO3 and 85% of the LiOH present in the as-given materials, and we observe that heat treatment in a stagnant atmosphere is less effective than treatment under active gas flow. We show that relithiation of the LLZO lattice improves Li + transport across the LLZO particle interface when immersed in a Li +-bearing organic electrolyte, and that the protonation of LLZO contributes more to slowing interfacial Li + transport than the presence of Li2CO3.

  PublisherOA PDFDOI

• Uniform pore structure enables negligible degradation in undoped and uncoated Ni-rich cathodes

  Nature Energy · 2026-03-02

  article
  PublisherDOI

• Key Parameters Controlling Energy Performance in Manganese Cathodes

  ChemRxiv · 2025-02-23

  preprintOpen access

  Ideal battery performance can be characterized by high energy density that remains stable over many charge-discharge cycles. While energy degradation is typically unavoidable as batteries age, we observed a unique phenomenon in cells using low-cost, high-manganese (Mn) disordered rocksalt-type cathodes: energy gains, accompanied by voltage stabilization during cycling—an effect linked to phase transformations. To understand and enhance this unconventional performance, we introduce a new methodology that identifies key Mn cathode parameters using newly proposed critical energy metrics, such as maximum energy density, total energy throughput, and energy degradation. Through a range of analytical techniques, we reveal how enhanced kinetics and facilitated phase transformations influence performance. Our analysis investigates cathode active material properties, including conductivity, particle morphology, length-dependent structure, chemical state distributions, and cathode reactivity under varying temperature, current, and voltage window. By mapping the interplay of these factors, our study provides a mechanistic understanding of the newly discovered phenomena that drive maximized energy density, along with strategies for materials engineering and electrochemical protocols to enhance battery efficiency and durability.

  PublisherOA PDFDOI

• Understanding the Cathode Electrochemistry of Humidified Solid‐State Lithium‐Oxygen Batteries

  Advanced Energy Materials · 2025-10-29

  articleSenior authorCorresponding

  Abstract Lithium‐oxygen batteries (LOBs) possess a high theoretical energy density, making them potential candidates for next‐generation energy storage. However, challenges such as reactive oxygen species‐induced component degradation hinder their practical use. Inorganic solid‐state electrolytes offer an alternative to degradation‐prone aprotic electrolytes, while also protecting lithium anodes from potential atmospheric reactants. This study explores the cathode electrochemistry of solid‐state LOBs using humidified oxygen, which forms an aqueous catholyte during initial cycling, thereby improving cathode‐electrolyte contact. To quantitatively analyze the cathode electrochemistry, a ‘Humidity‐Incorporated’ Differential Electrochemical Gas Monitoring System (HiDEMS) is developed to control humidity and monitor gas consumption and evolution in real time. When studying a Li‐O 2 cell that employs a NASICON‐type Li 1.3 Al 0.3 Ti 1.7 (PO 4 ) 3 (LATP) solid electrolyte and a porous carbon cathode, a shift in discharge products from Li 2 O 2 to LiOH is observed over repeated cycles. While Li 2 O 2 evolves O 2 during charging, LiOH oxidation leads to minimal O 2 release and increased CO 2 production, originating from oxidation of carbon electrodes. Further, dissolution of Al and P from LATP is observed, likely driven by the formation of the alkaline catholyte. The findings highlight the need for carbon‐free cathode materials and more stable solid‐state conductors to minimize side reactions and improve rechargeability in humidified solid‐state Li‐O 2 batteries.

  PublisherDOI

• Disordered Rocksalts as High‐Energy and Earth‐Abundant Li‐Ion Cathodes

  Advanced Materials · 2025-05-06 · 20 citations

  reviewOpen access

  To address the growing demand for energy and support the shift toward transportation electrification and intermittent renewable energy, there is an urgent need for low-cost, energy-dense electrical storage. Research on Li-ion electrode materials has predominantly focused on ordered materials with well-defined lithium diffusion channels, limiting cathode design to resource-constrained Ni- and Co-based oxides and lower-energy polyanion compounds. Recently, disordered rocksalts with lithium excess (DRX) have demonstrated high capacity and energy density when lithium excess and/or local ordering allow statistical percolation of lithium sites through the structure. This cation disorder can be induced by high temperature synthesis or mechanochemical synthesis methods for a broad range of compositions. DRX oxides and oxyfluorides containing Earth-abundant transition metals have been prepared using various synthesis routes, including solid-state, molten-salt, and sol-gel reactions. This review outlines DRX design principles and explains the effect of synthesis conditions on cation disorder and short-range cation ordering (SRO), which determines the cycling stability and rate capability. In addition, strategies to enhance Li transport and capacity retention with Mn-rich DRX possessing partial spinel-like ordering are discussed. Finally, the review considers the optimization of carbon and electrolyte in DRX materials and addresses key challenges and opportunities for commercializing DRX cathodes.

  PublisherDOI

• pH-dependent Scaling Relations and Ion Insertion Promote Bifunctional Oxygen Electrocatalysis on MnO2

  ChemRxiv · 2025-10-14

  preprint

  Designing electrocatalysts that efficiently mediate both the oxygen evolution reaction (OER) and the oxygen reduction reaction (ORR) remains a central challenge in electrochemical energy conversion and storage. Most catalysts exhibit activity for one reaction at the expense of the other due to adsorbate scaling relations. Here, we report that 𝛼-KxMnO2 defies this trade-off, exhibiting simultaneous improvements for both OER and ORR with increasing electrolyte pH. Using rotating ring disk electrochemistry (RRDE), high-resolution transmission electron microscopy (HRTEM), and operando X-ray and infrared spectromicroscopies, we rule out morphological changes and site blocking as causes of this unusual pH effect. Instead, grand-canonical DFT shows that a pH-dependent interfacial electric field strengthens the adsorption of key intermediates at high pH, leading to non-Nernstian shifts towards lower overpotentials. Simultaneously, electrochemical K+ (de)insertion promotes high bifunctional activity by stabilizing Mn3+ sites for ORR and Mn4+ sites for OER. These mechanistic findings establish a generalizable strategy for breaking conventional catalytic trade-offs by coupling electrolyte engineering and ion insertion to enhance electrocatalytic performance.

  PublisherDOI

• Quantifying Phase Contributions to Ion Transport in Organic–Inorganic Composite Electrolytes

  Journal of the American Chemical Society · 2025-12-08 · 3 citations

  articleSenior authorCorresponding

  Polymer-ceramic composite electrolytes represent a promising strategy for realizing solid-state batteries. However, ion transport in such organic–inorganic hybrid systems remains poorly understood. Here, we reveal the mechanism of ion transport in model hybrid electrolytes composed of Li1.3Al0.3Ti1.7P3O12 (LATP) particles and various highly concentrated liquid electrolytes with conductivities similar to those of polymer electrolytes. By comparing the impedance responses of LATP particles suspended in Li+ electrolytes and in K+ electrolytes, where LATP particles are not DC-conductive, we accurately quantify the contribution of LATP to the overall hybrid electrolyte conductivity. This further allows calculation of particle interfacial resistances and overall hybrid electrolyte transference numbers. Our study indicates that solvent’s Li+ solvation strength, Li+ transference number in the organic phase, and inorganic particle size are critical factors governing Li+ conductivity of hybrid electrolytes, suggesting single-ion conducting polymer matrices, in combination with large inorganic particles and plasticizers facilitating Li+ desolvation, are favored when designing polymer-ceramic composite electrolytes.

  PublisherDOI

• Alternative Solid‐State Synthesis Route for Highly Fluorinated Disordered Rock‐Salt Cathode Materials for High‐Energy Lithium‐Ion Batteries

  Advanced Energy Materials · 2025-04-08 · 7 citations

  articleOpen access

  Abstract Fluorination has been identified as a key element for enabling the stable cycling of earth‐abundant manganese‐based disordered rock salt (DRX) cathodes. However, fluorination in the DRX bulk remains a challenge for scalable solid‐state synthesis. In this study, a tailored reaction pathway is proposed to synthesize a highly fluorinated DRX. It is demonstrated for the first time that the unconventional precursors, Li 6 MnO 4 , MnF 2 , and TiO 2 , can avoid the formation of Mn‐based intermediates (such as Li 2 (Mn,Ti)O 3, LiMnO 2 , and Mn 3 O 4 ), which, once formed, persist until the synthesis temperature reaches close to or above that required for fluorine volatility. Therefore, this method can form a highly fluorinated DRX with a composition of Li 1.23 Mn 0.40 Ti 0.37 O 2−y F y ( y = 0.29–0.34) at a low temperature (800 °C) relative to that required for conventional DRX solid‐state reactions (≥900 °C). Li 1.23 Mn 0.40 Ti 0.37 O 2−y F y ( y = 0.29–0.34) delivers a specific capacity above 300 mAh g −1 and a specific energy of 980 Wh kg −1 at 30 °C. Detailed characterization reveals that this DRX phase reversibly utilizes Mn 2+/3+ redox in the low‐voltage region and Mn 3+/4+ redox in the middle‐voltage range, whereas reversible oxygen redox is observed at high potentials.

  PublisherOA PDFDOI

• Mechanistic Studies of Oxidative Degradation in Diamine-Appended Metal–Organic Frameworks Exhibiting Cooperative CO ₂ Capture

  Journal of the American Chemical Society · 2025-07-10 · 5 citations

  articleOpen access

  Understanding the impact of O2 during a carbon capture process is vital for designing robust, cost-effective materials for carrying it out. However, mechanistic studies of the O2-induced degradation of materials are not easily undertaken owing to the complex sequential reaction pathways that arise. Here, we report comprehensive mechanistic investigations of the O2-induced degradation of diamine-appended metal–organic frameworks (MOFs) exhibiting cooperative CO2 adsorption. Oxygen exposure experiments were performed on seven different diamine-appended MOFs, including e-2–Mg2(dobpdc) (e-2 = N-ethylethylenediamine, dobpdc4– = 4,4′-dioxidobiphenyl-3,3′-dicarboxylate), under various temperatures and O2 pressures. These experiments show that diamine degradation inhibits CO2 chemisorption and that the degradation rate is significantly influenced by the diamine structure. In contrast, the parent frameworks remain essentially intact upon O2 exposure. Detailed characterization of O2-exposed e-2–Mg2(dobpdc) revealed the formation of various degradation products, including acetaldehyde, carbon dioxide, water, ethylamine, and other aldehyde- and imine-containing species. Together, these observations suggest that diamine degradation occurs via C–N bond cleavage through pathways involving C-centered radicals. Furthermore, computational evaluation of the initiation and propagation pathways for amine degradation in diamine-appended MOFs indicates that (i) degradation is likely initiated by OH•, (ii) carbon-centered radicals generated via radical transfer reactions react with O2, leading to amine degradation, and (iii) the rate-limiting step of the degradation reactions likely involves O–O bond cleavage. Overall, these mechanistic insights could inform strategies for mitigating O2-induced amine degradation in next-generation carbon capture technologies.

  PublisherDOI

Recent grants

• Collaborative Research: Understanding ion solvation effects in nonaqueous oxygen electroreduction reactions

  NSF · $202k · 2016–2019

• CAREER: Novel redox-active electrolyte additives to enhance efficiency and direct product selectivity in electroreduction reactions

  NSF · $504k · 2017–2023

Frequent coauthors

• Joseph K. Papp

  University of California, Berkeley

  88 shared

• A. C. Luntz

  SLAC National Accelerator Laboratory

  65 shared

• Elizabeth R. Corson

  65 shared

• Matthew J. Crafton

  University of California, Berkeley

  61 shared

• Tzu‐Yang Huang

  Institute of Chemistry, Academia Sinica

  60 shared

• Sara E. Renfrew

  University of California, Berkeley

  58 shared

• Jeffrey J. Urban

  Lawrence Berkeley National Laboratory

  57 shared

• Kara D. Fong

  University of Cambridge

  56 shared

Awards & honors

• Mellichamp Distinguished Lectureship, Georgia Tech (2017)
• Advanced Energy Storage Scialog Fellow (2017)
• NSF CAREER Award (2017-2022)
• VW/BASF Science Award Electrochemistry (2015)
• Early Career Analytical Electrochemistry Prize of the Intern…