Will Gent received his BA in Chemistry from Cornell in 2013, where he worked with Prof. Geoff Coates to develop new polymer electrolytes for lithium ion batteries. He received his MS and PhD from Stanford in 2019, where he worked with Prof. Will Chueh using advanced X-ray and electrochemical techniques to study redox and degradation mechanisms in lithium ion battery cathode materials. Will is now a staff scientist within the Stanford StorageX initiative, an industrial affiliates program that coordinates interdisciplinary, application-driven research in energy storage. He currently leads several research projects aimed at improving the performance and cost of lithium ion batteries through materials engineering and the use of data-driven approaches to accelerate testing, optimization, and validation of new energy storage concepts.
Phys Sci Res Assoc, Materials Science and Engineering
PhD, Stanford University, Chemistry (2019)
MS, Stanford University, Chemistry (2019)
BA, Cornell University, Chemistry (2013)
- High Reversibility of Lattice Oxygen Redox Quantified by Direct Bulk Probes of Both Anionic and Cationic Redox Reactions JOULE 2019; 3 (2): 518–41
Metal-oxygen decoordination stabilizes anion redox in Li-rich oxides.
Reversible high-voltage redox chemistry is an essential component of many electrochemical technologies, from (electro)catalysts to lithium-ion batteries. Oxygen-anion redox has garnered intense interest for such applications, particularly lithium-ion batteries, as it offers substantial redox capacity at more than 4V versus Li/Li+ in a variety of oxide materials. However, oxidation of oxygen is almost universally correlated with irreversible local structural transformations, voltage hysteresis and voltage fade, which currently preclude its widespread use. By comprehensively studying the Li2-xIr1-ySnyO3 model system, which exhibits tunable oxidation state and structural evolution with y upon cycling, we reveal that this structure-redox coupling arises from the local stabilization of short approximately 1.8A metal-oxygen pi bonds and approximately 1.4A O-O dimers during oxygen redox, which occurs in Li2-xIr1-ySnyO3 through ligand-to-metal charge transfer. Crucially, formation of these oxidized oxygen species necessitates the decoordination of oxygen to a single covalent bonding partner through formation of vacancies at neighbouring cation sites, driving cation disorder. These insights establish a point-defect explanation for why anion redox often occurs alongside local structural disordering and voltage hysteresis during cycling. Our findings offer an explanation for the unique electrochemical properties of lithium-rich layered oxides, with implications generally for the design of materials employing oxygen redox chemistry.
View details for PubMedID 30718861
- Coupling between oxygen redox and cation migration explains unusual electrochemistry in lithium-rich layered oxides NATURE COMMUNICATIONS 2017; 8
Persistent State-of-Charge Heterogeneity in Relaxed, Partially Charged Li1- x Ni1/3 Co1/3 Mn1/3 O2 Secondary Particles.
2016; 28 (31): 6631-6638
Ex situ transmission X-ray microscopy reveals micrometer-scale state-of-charge heterogeneity in solid-solution Li1- x Ni1/3 Co1/3 Mn1/3 O2 secondary particles even after extensive relaxation. The heterogeneity generates overcharged domains at the cutoff voltage, which may accelerate capacity fading and increase impedance with extended cycling. It is proposed that optimized secondary structures can minimize the state-of-charge heterogeneity by mitigating the buildup of nonuniform internal stresses associated with volume changes during charge.
View details for DOI 10.1002/adma.201601273
View details for PubMedID 27187238
Effects of Particle Size, Electronic Connectivity, and Incoherent Nanoscale Domains on the Sequence of Lithiation in LiFePO4 Porous Electrodes
2015; 27 (42): 6591-?
High-resolution X-ray microscopy is used to investigate the sequence of lithiation in LiFePO4 porous electrodes. For electrodes with homogeneous interparticle electronic connectivity via the carbon black network, the smaller particles lithiate first. For electrodes with heterogeneous connectivity, the better-connected particles preferentially lithiate. Correlative electron and X-ray microscopy also reveal the presence of incoherent nanodomains that lithiate as if they are separate particles.
View details for DOI 10.1002/adma.201502276
View details for Web of Science ID 000364700200004
View details for PubMedID 26423560
- Dichotomy in the Lithiation Pathway of Ellipsoidal and Platelet LiFePO4 Particles Revealed through Nanoscale Operando State-of-Charge Imaging ADVANCED FUNCTIONAL MATERIALS 2015; 25 (24): 3677-3687