About

Kent Griffith is an Assistant Professor in the Program in Materials Science and Engineering at the University of California, San Diego. His research combines inorganic solid-state chemistry, electrochemistry, and advanced in-situ characterization techniques to understand reaction and degradation pathways in battery and other energy materials. His work involves a diverse range of synthetic approaches and expertise in solid-state NMR spectroscopy, X-ray/neutron diffraction and spectroscopy, DFT, and electrochemical characterization. Prof. Griffith’s research includes both fundamental and applied projects, with the latter conducted in close collaboration with industrial partners and standards. He holds a B.S. in Chemistry from Indiana University and a Ph.D. in Chemistry from the University of Cambridge.

Research topics

• Materials science
• Chemistry
• Physical chemistry
• Nanotechnology
• Thermodynamics
• Physics
• Crystallography
• Electrical engineering
• Inorganic chemistry
• Stereochemistry
• Engineering physics
• Engineering
• Optoelectronics
• Process engineering
• Organic chemistry
• Chemical engineering
• Metallurgy
• Computational chemistry
• Geology
• Chemical physics
• Composite material

Selected publications

• Crystallography and Defect Structure of Alkaline-Earth Hexaborides─CaB ₆ , SrB ₆ , and BaB ₆ ─Doped with Lithium

  Inorganic Chemistry · 2026-05-15

  articleCorresponding

  We explore the effects of lithium doping on the structure of three alkaline-earth hexaborides─CaB6, SrB6, and BaB6. Lithium incorporation was characterized using inductively coupled plasma mass spectrometry and X-ray diffraction analyses, demonstrating a systematic expansion of the cubic Pm3̅m lattice with increasing lithium concentration. Scanning and transmission electron microscopy revealed that lithium doping induces distinct surface pitting and localized lattice distortions. Solid-state 7Li nuclear magnetic resonance (NMR) spectroscopy provided deeper insight into the lithium coordination environments. One-dimensional NMR confirmed the ionic character of lithium and demonstrated the presence of minor side products, which were largely eliminated by acid treatment of the powders. Two-dimensional exchange spectroscopy NMR identified two distinct ionic lithium environments within the BaB6 lattice. The absence of cross-peaks with side-product signals confirmed spatial separation and chemical stability of lattice-confined lithium. Our analyses establish a foundational understanding of alkali metal doping behavior in boron-rich ceramics and highlight the structural role of lithium as a dopant in hexaboride systems, supporting future investigations into how lithium incorporation may influence electronic properties.

  PublisherDOI

• CSD 2496561: Experimental Crystal Structure Determination

  Open MIND · 2026-02-16

  datasetOpen accessSenior author

  An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  OA PDFDOI

• Lithium and Sodium Intercalation with Multielectron Redox in Vacancy Ordered and Vacancy Disordered Cation-Deficient Anti-NASICON Niobium(V) Phosphates

  Journal of the American Chemical Society · 2026-02-16

  articleSenior authorCorresponding

  Understanding structure–property relationships is of fundamental importance for the discovery and engineering of functional materials. In this work, two niobium(V) phosphate materials are studied for the first time as electroactive intercalation hosts after probing their crystal chemistry and defect structures with a combined high-resolution and wide-line NMR crystallography approach to resolve outstanding structural questions. The relatively rare niobyl group (Nb═O) gives an exceptionally distinct 93Nb NMR signature under the right experimental conditions, even in the presence of disorder, which should lead to its discovery and analysis in other phases. Nb5P7O30 and Nb2–xP3–yO12 provide an interesting model case study for comparative analysis because they are nearly isocompositional and both crystallize in the anti-NASICON structure, but they adopt different vacancy (dis)order patterns that lead to distinct space-group symmetries. As intercalation hosts, they both exhibit multielectron Nb5+/Nb3+ redox with lithium, with peak-to-peak separations on the order of 10 mV, and full one-electron Nb5+/Nb4+ redox with sodium. This latter observation is notable because the various niobium(V) oxide polymorphs, widely studied as battery electrode materials, are essentially inactive to sodium. Operando synchrotron diffraction with fine temporal resolution shows that Li5zNb5P7O30 undergoes a series of six minimal-strain displacive phase transitions during lithium insertion, while the lithiation of Li1.92zNb2–xP3–yO12 is purely bulk solid solution. The final volume change of Li5zNb5P7O30 to z = 1 is 1.3% and to z = 1.45 is 2.4%, while the expansion for Li1.92zNb2–xP3–yO12 to z = 1 is 3.5% and to z = 1.41 is 4.3%. Interstitial intercalation sites and percolation pathways are identified with bond valence site energy searching. Comparisons of the nonstoichiometric niobium(V) phases in this work are made to stoichiometric phases in the anti-NASICON system, as well as the effects of order and disorder in the lithium metal phosphate olivines.

  PublisherDOI

• CSD 2496563: Experimental Crystal Structure Determination

  The Cambridge Structural Database · 2026-02-16

  datasetOpen accessSenior author

  An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

  PublisherDOI

• Superionic Surface Li-Ion Transport in Carbonaceous Materials

  Nano Letters · 2025-08-15 · 5 citations

  articleOpen access

  Unlike Li-ion transport in the bulk of carbonaceous materials, little is known about Li-ion diffusion on their surface. In this study, we have discovered an ultrafast Li-ion transport phenomenon on the surface of carbonaceous materials with limited reversible Li insertion capacity and high surface area. An ionic conductivity of 18.1 mS cm–1 at room temperature is observed in lithiated Ketjen black (KB), far exceeding those of most solid-state ion conductors. Theoretical calculations reveal low diffusion barriers for the surface Li species. As a result, lithiated KB functions effectively as an interlayer between Li and solid-state electrolytes (SSEs) to mitigate dendrite growth. Further, lithiated KB acts as a high-performance mixed ionic–electronic conductor and replaces solid electrolytes to enhance graphite anode performance, demonstrating full utilization with ∼85% capacity retention over 300 cycles. The discovery of this surface-mediated ultrafast Li-ion transport mechanism provides new directions for the design of solid-state ion conductors and solid-state batteries.

  PublisherOA PDFDOI

• Extreme Defect Tolerance for Electrochemical Intercalation in Wadsley–Roth Structures Demonstrated by Metastable NaNb ₇ O ₁₈

  Journal of the American Chemical Society · 2025-02-03 · 2 citations

  articleOpen accessSenior authorCorresponding

  Careful control over the defect chemistry of crystalline compounds is typically critical to transport phenomena (ion, electron, phonon). In one-dimensional (1D) ion conductors, even small concentrations of defects in the diffusion pathway can be pernicious. Wadsley–Roth block phases are 1D ion conductors with high redox capacity and among the highest diffusivity of any battery electrode materials. The origin of their high-rate transport has been attributed to parallel tunnels that could impart defect tolerance, but direct evidence is limited. Herein, a new lithium-ion battery negative electrode material, NaNb7O18, is described that exhibits extreme defect tolerance. Multimodal characterization combining neutron diffraction, 23Na solid-state NMR spectroscopy, and DFT calculations reveals that more than half of the Na+ in NaNb7O18 is in diffusion tunnel-blocking cuboctahedral environments (similar to the perovskite A-site). Despite the high point-defect concentration, NaNb7O18 can reversibly lithiate to Li7NaNb7O18 and cycle 200 mAh·g–1 in 10 h and 100 mAh·g–1 in 3 min in large 4–23 μm (D10–D90) particles. Operando synchrotron diffraction shows an anisotropic and asymmetric lithiation/delithiation process with two first-order phase transitions including one with nearly zero volume change. LixNaNb7O18 also exhibits evidence for reversible Nb–Nb bond formation. From the same operando diffraction measurements, Nb–Nb distances between edge-sharing octahedra at the block peripheries vary from ca. 3.4 to 2.8 and back to 3.4 Å over one lithium insertion/extraction cycle, in quantitative agreement with the Nb–Nb bond formation charge storage mechanism recently proposed from the computational lithiation of several different Wadsley–Roth compounds.

  PublisherOA PDFDOI

• Lithium and Sodium Intercalation with Multi-electron Redox in Vacancy Ordered and Vacancy Disordered Cation-Deficient Anti-NASICON Niobium(V) Phosphates

  ChemRxiv · 2025-10-28

  articleSenior author

  Understanding structure–property relationships is of fundamental importance for the discovery and engineering of functional materials. In this work, two niobium(V) phosphate materials are studied for the first time as electroactive intercalation hosts after probing their crystal chemistry and defect structures with a combined high-resolution and wideline NMR crystallography approach to resolve outstanding structural questions. The relatively rare niobyl group (Nb=O) gives an exceptionally distinct 93Nb NMR signature under the right experimental conditions, even in the presence of disorder, which should lead to its discovery and analysis in other phases. Nb5P7O30 and Nb2–xP3–yO12 provide an interesting model case study for comparative analysis because they are nearly isocompositional and both crystallize in the anti-NASICON structure, but they adopt different vacancy (dis)order patterns that lead to distinct space-group symmetries. As intercalation hosts, they both exhibit multi-electron Nb5+/Nb3+ redox with lithium, with peak-to-peak separations on the order of 10 mV, and full one-electron Nb5+/Nb4+ redox with sodium. This latter observation is notable because the various niobium(V) oxide polymorphs, widely studied as battery electrode materials, are essentially inactive to sodium.

  PublisherDOI

• Tailoring Chloride Solid Electrolytes for Reversible Redox

  Journal of the American Chemical Society · 2025-05-28 · 19 citations

  articleOpen accessCorresponding

  Solid-state electrolytes enable next-generation batteries that can theoretically deliver higher energy densities while improving device safety. However, when fabricating cathodes for all-solid-state batteries, solid-state electrolytes must be combined with the active materials in high weight fractions in order to achieve sufficient ionic percolation within the cathode composite. This requirement drastically hinders the practicality of solid-state batteries as the solid-state electrolyte is conventionally designed to be electrochemically inactive and is effectively electrochemical “dead weight”, lowering both the gravimetric and volumetric energy density of the cell. In this work, a well-known solid-state electrolyte, Na2ZrCl6, is modified by aliovalent substitution of inactive Zr4+ cations with redox-active M5+ (M = Nb or Ta) cations to create a series of Na2–xMxZr1–xCl6 solid solutions that possess both high ionic conductivities and active sites for Na+ storage. The Na+ intercalation mechanisms of these solid-solution materials, in addition to those of the NaMCl6 end-member materials, are elucidated in this work. It was discovered that both the niobium- and tantalum-containing chlorides exhibit rather high electrochemical potentials (2.2–2.8 V vs Na9Sn4), making them ideal catholytes to pair with commonly used oxide cathode materials like NaCrO2. This synergistic pairing leads to a cathode composite with an 83–102% increase in energy density and 39–81% improvement in areal discharge capacity compared to a redox-innocent solid electrolyte. This approach highlights the benefits of designing and employing redox-active solid-state electrolytes that can reversibly intercalate charge-carrying cations, opening up a broad new avenue for solid-state electrolyte discovery and solid-state battery design.

  PublisherDOI

• Structural Evolution during Chemical and Electrochemical Intercalation Reactions Probed with X-rays, Neutrons, and RF Pulses

  Structural Dynamics · 2025-09-01

  articleOpen accessSenior author

  Electrochemical energy storage is an enabling technology for personal and industrial electronics, adoption of intermittent renewable energy, and the electrification of transportation. From a fundamental solid-state chemistry perspective, and in the context of batteries, it is interesting to explore new mixed ionic–electronic conductors that can withstand large changes in composition and electronic configuration over ∼1000 charge– discharge cycles to function as electrode materials and to explore new pure ion conductors with extremely low electronic conductivities that could function as solid electrolytes or interfacial coatings. Understanding the mechanisms that facilitate ion and/or electron transport or induce material degradation are the keys to discovering and engineering the next generation of battery materials. Relatively few unique crystal structures underpin most battery materials. We are particularly interested in novel complex oxides that might offer new insights into structure–property relationships or even new performance characteristics. This talk will focus on recent examples from our lab: (i) defects, electrochemistry, and metal–metal bonding in NaNb7O18 and NaNb13O33 framework structures (Wadsley–Roth derivatives) with tunnel-blocking defects, and (ii) new lithium-rich “layered” structures, Li3MO4 (M = Nb, Ta) synthesized via instantaneous ion exchange in a molten salt flux. Both families of materials are characterized with an ‘NMR crystallography’ approach that combines X-ray and neutron diffraction with DFT-supported solid-state NMR spectroscopy.

  PublisherDOI

• Metastable Sodium closo-Hydroborates for Low Temperature All-Solid-State Battery with Thick Cathode

  ChemRxiv · 2025-02-21

  preprintOpen access

  All-solid-state batteries featuring a thick cathode layer paired with a high-capacity alloy anode offer enhanced energy density1,2 and reliable performance, even at subzero temperatures, can outperform their liquid-based counterparts. Enabling such technology requires a solid electrolyte with high ionic conductivity, mechanical formability, and excellent electrochemical stability3. While non-close-packed frameworks offer lower symmetry and irregular coordination between mobile ions and anions due to distortion, resulting in higher ionic conductivity4,5, fast ionic diffusion in hydroborate chemistry is often associated with close-packed or cubic anion frameworks6-9. Here, we demonstrate that a metastable, non-close-packed orthorhombic Na3(B12H12)(BH4) phase possesses superionic conductivity of 4.6 mS cm−1 at 30 °C, three orders of magnitude improvement over its precursors, alongside excellent reduction stability. High-throughput molecular dynamic simulations reveal that the propensity for anion motion significantly enhances the population of highly mobile Na+ without affecting the activation energy. By leveraging its high conductivity across a wide temperature range, this material enables the development of all-solid-state sodium-ion batteries with ultra-thick cathodes, delivering reliable functionality at room temperature and in subzero environments. This study expands our understanding of hydroborate-based solid electrolytes, highlighting their potential for high ionic conductivity and broad electrochemical stability windows in next-generation energy storage systems.

  PublisherOA PDFDOI

Frequent coauthors

• Kenneth R. Poeppelmeier

  Northwestern University

  62 shared

• Clare P. Grey

  University of Cambridge

  60 shared

• Gerbrand Ceder

  University of California, Berkeley

  32 shared

• David O. Scanlon

  28 shared

• Yunyeong Choi

  27 shared

• Justin C. Hancock

  Northwestern University

  27 shared

• Andrew J. Morris

  University of Birmingham

  23 shared

• Warda Rahim

  University College London

  22 shared

Education

• B.S.

  Indiana University

• Ph.D.

  University of Cambridge