A5040196078- Advancements in Battery Materials
- Advanced Battery Materials and Technologies
- Advanced Battery Technologies Research
- Extraction and Separation Processes
- Advanced battery technologies research
- Supercapacitor Materials and Fabrication
- CO2 Reduction Techniques and Catalysts
- Electrocatalysts for Energy Conversion
- Semiconductor materials and devices
- Molecular Junctions and Nanostructures
- Advanced Photocatalysis Techniques
- Ionic liquids properties and applications
- Chalcogenide Semiconductor Thin Films
- Thermal Expansion and Ionic Conductivity
- Fuel Cells and Related Materials
- Molten salt chemistry and electrochemical processes
- Catalytic Processes in Materials Science
- Polyoxometalates: Synthesis and Applications
- Electron and X-Ray Spectroscopy Techniques
- Advancements in Solid Oxide Fuel Cells
- Carbon Dioxide Capture Technologies
- Electrophoretic Deposition in Materials Science
- Solid-state spectroscopy and crystallography
- Fiber-reinforced polymer composites
University of Delaware
2019-2024
Argonne National Laboratory
2017-2021
Massachusetts Institute of Technology
2011-2016
The O2electrode in Li–O2cells was shown to exhibit gravimetric energy densities (considering the total weight of oxygen electrode discharged state) four times that LiCoO2 with comparable power. discharge rate capability Au-catalyzed Vulcan carbon and pure (VC) as studied range 100 2000 mA gcarbon−1. voltage capacity Li−O2 cells were decrease increasing rates. Unlike propylene carbonate based electrolytes, tested 1,2-dimethoxyethane found not be limited by transport electrolyte. X-Ray...
Understanding the thermal stability of major reaction products, Li2O2 (space group P63/mmc) and Li2O ) is critical to improve safety characteristics Li-air batteries. The changes in crystal structure surface chemistry were examined as a function temperature via situ X-ray diffraction (XRD) photoelectron spectroscopy (XPS). Significant decreases lattice parameters c/a ratio found at 280°C higher. These structural can be attributed transformation Li2O2-δ, which supported by density functional...
Battery performance is strongly correlated with electrode microstructural properties. Of the relevant properties, tortuosity factor of electrolyte transport paths through microstructure pores important as it limits battery maximum charge/discharge rate, particularly for energy-dense thick electrodes. Tortuosity however, difficult to precisely measure, and thus its estimation has been debated frequently in literature. Herein, three independent approaches have applied quantify lithium-ion The...
Abstract Due to the high lithium capacity of silicon, composite (blended) electrodes containing silicon (Si) and graphite (Gr) particles are attractive alternatives all‐Gr used in conventional lithium‐ion batteries. In this Communication, lithiation delithiation Si Gr a 15 wt% electrode is quantified for each component using energy dispersive X‐ray diffraction. This quantification important as components cycle different potential regimes, interpretation cycling behavior complicated by...
Spatial distribution of lithium cations in the graphite electrode a lithium-ion battery is quantified using <italic>operando</italic> energy dispersive X-ray diffraction.
Abstract Electrochemical processes in lithium–oxygen (Li–O 2 or Li–air) batteries are complex, with chemistry depending on cycling conditions, electrode materials and electrolytes. In non‐aqueous Li–O cells, reversible lithium peroxide (Li O ) irreversible parasitic products (i.e., LiOH, Li CO 3 , O) common. Superoxide intermediates (O − LiO contribute to the formation of these species transiently stable their own right. While characterization techniques like XRD, XPS FTIR have been used...
Galvanostatic intermittent titration technique (GITT) – a popular method for characterizing kinetic and transport properties of battery electrodes is predicated on the proper evaluation electrode active area. LiNi0.5044Co0.1986Mn0.2970O2 (NCM523) material exhibits complex morphology in which sub-micron primary particles aggregate to form secondary particle agglomerates. This work proposes new area formulation primary/secondary agglomerate materials better mimic NCM532 electrodes. then...
Understanding the oxygen reduction reaction kinetics in presence of Na ions and formation mechanism discharge product(s) is key to enhancing Na–O2 battery performance. Here we show NaO2 as only product from cells with carbon nanotubes 1,2-dimethoxyethane X-ray diffraction Raman spectroscopy. Sodium peroxide dihydrate was not detected discharged electrode up 6000 ppm H2O added electrolyte, but it ambient air exposure. In addition, that sizes distributions can be highly dependent on rate,...
Solid-state activation of Li<sub>2</sub>O<sub>2</sub> oxidation is mediated by chemical conversion with slow kinetics to a lithium metal oxide generally faster kinetics.
Reducing the energy loss associated with Li2O2 electrochemical oxidation is paramount to development of efficient rechargeable lithium–oxygen (Li–O2) batteries for practical use. The influence a series perovskites different eg filling on kinetics was examined using Li2O2-prefilled electrodes. While LaCrO3 inactive oxygen evolution upon water in alkaline solution, it found provide highest specific current towards among all examined. Further exploration Cr-based catalysts showed that Cr...
Redox mediators hold significant promise in reducing the large overpotentials pervasive upon charging of lithium–oxygen (Li–O2) cells. Cobalt bis(terpyridine) (Co(Terp)2) was investigated as a mediator Li–O2 reaction using electrochemical, XRD, and mass spectrometry measurements benchmarked against tetrathiafulvalene (TTF). Significant reductions reversible potential versus Li+/Li are measured for Co(Terp)2 TTF from diglyme to Pyr14TFSI:diglyme Pyr14TFSI, attributable upward shift electrode,...
Charging kinetics and reversibility of Na-O2 batteries can be influenced greatly by the particle size NaO2 formed upon discharge, exposure time (reactivity) to electrolyte. Micrometer-sized cubes at high discharge rates were charged smaller overpotentials compared nanometer-sized counterparts low rates.
Rapid charging of lithium-ion batteries being developed for electric vehicles is a formidable challenge. Electrochemical polarization cells during fast favors deposition metallic Li onto the surface graphite electrode, and this plating compromises safety accelerates performance degradation. Observing onset nucleation essential elucidation mechanisms defining conditions favoring plating, but presently available methods are not sufficiently sensitive selective while also allowing satisfactory...
Galvanostatic intermittent titration experiments were performed in three-electrode cells to characterize the effect of C/2, 2-C and 4-C charge rates on observed lithium diffusion coefficient. As part data analysis process, we compared classic Weppner-Huggins polarization with a newer (Wang et al.) method for depolarization data. At low values x LixC6, both methods showed same general trend apparent coefficient, > C/2. The two techniques differed magnitude estimated coefficient by about...
The cycling of next-generation, high-capacity silicon (Si) anodes capable 3579 mAh·g-1 is greatly hindered by the instability solid-electrolyte interphase (SEI). large volume changes Si during (de)lithiation cause continuous cracking SEI and its reconstruction, leading to loss lithium inventory extensive consumption electrolyte. formed in situ cell mostly composed molecular fragments oligomers, structure which difficult tailor. In contrast, ex formation a synthetic provides greater...
In this study Cu, Sn, and bimetallic CuSn x nanoparticles were synthesized evaluated as electrocatalysts for CO 2 reduction using zero gap membrane electrode assemblies. Results show with Sn contents above 10% yield formate a primary product Faradaic Efficiencies near 70% at 350 mA cm −2 . Cu-Sn less than current densities below relatively lower cell potentials. When the low-Sn content in alkaline anolytes , ethanol was recorded (FE = 48.5% E ≥ 3.0 V). We propose enhanced C activity...
Lithium sulfur (Li–S) batteries have received significant attention as one of the energy storage systems with excellent prospects for emerging applications due to their high density and low-cost. However, there are fundamental challenges impeding commercialization Li–S batteries. Notorious among those is “polysulfide shuttle” consisting dissolution into electrolyte solvent subsequent crossover anode long-chain lithium polysulfides. Sparingly solvating electrolytes been exploited an approach...
This Cover Feature highlights how Raman spectroscopy is an essential tool for studying product chemistry and mechanisms in situ Li–O2 battery systems. More details can be found the Minireview by A. D. Taylor et al. on page 1446 Issue 10, 2015 (DOI: 10.1002/celc.201500218).
The silicon solid electrolyte interphase (SEI) faces cyclical cracking and reconstruction due to the ∼350% volume expansion. Understanding SEI dynamic morphology chemistry evolution from delithiated lithiated states is thereby paramount engineering a stable Si anode. Fluoroethylene carbonate (FEC) preferred additive with widely demonstrated enhancement of cycling. Thus, insights into dynamics FEC-SEI may provide hints toward interface. Herein, complementary ATR-FTIR, AFM, tip IR, XPS probing...
The capacity retention of high-capacity cobalt-free LiNiO 2 can be doubled by surface α -LiGaO .