Gordon L. Graff's research while affiliated with Pacific Northwest National Laboratory and other places

Publications (91)

Article
The unstable interface of lithium (Li) metal in high energy density Li sulfur (Li-S) batteries raises concerns of poor cycling, low efficiency and safety issues, which may be addressed by using intercalation types of anode. Herein, a new prototype of Li-ion sulfur battery with high performance has been demonstrated by coupling a graphite anode with...
Article
High energy and cost-effective lithium sulfur (Li–S) battery technology has been vigorously revisited in recent years due to the urgent need of advanced energy storage technologies for green transportation and large-scale energy storage applications. However, the market penetration of Li–S batteries has been plagued due to the gap in scientific kno...
Patent
A tool for depositing multilayer coatings onto a substrate. In one configuration, the tool includes a includes an in-line organic material deposition station operating under at least one of a pressure or temperature controlled environment. In another, it further is of a hybrid design that incorporates both in-line and cluster tool features. In this...
Article
In recent years, the Li metal anode has regained a position of paramount research interest because of the necessity for employing Li metal in next-generation battery technologies such as Li-S and Li-O2. Severely limiting this utilization, however, are the rapid capacity degradation and safety issues associated with rechargeable Li metal anodes. A f...
Article
Functionalized graphene sheets (FGSs) comprise a unique member of the carbon family, demonstrating excellent electrical conductivity and mechanical strength. However, the detailed chemical composition of this material is still unclear. Herein, we take advantage of the fluorination process to semiquantitatively probe the defects and functional group...
Article
Full-text available
Lithium (Li) dendrite formation is one of the critical challenges for rechargeable Li metal batteries. The traditional method of suppressing Li dendrites, by using high-quality solid electrolyte interphase films, cannot effectively solve this problem. Recently, we proposed a novel self-healing electrostatic shield (SHES) mechanism to achieve dendri...
Article
A cost model is developed for all vanadium and iron-vanadium redox flow batteries. Electrochemical performance modeling is done to estimate stack performance at various power densities as a function of state of charge and operating conditions. This is supplemented with a shunt current model and a pumping loss model to estimate actual system efficie...
Article
Full-text available
Lithium-sulphur batteries have high theoretical energy density and potentially low cost, but significant challenges such as severe capacity degradation prevent its widespread adoption. Here we report a new design of lithium-sulphur battery using electrically connected graphite and lithium metal as a hybrid anode to control undesirable surface react...
Article
Silicon is environmentally benign and ubiquitous. Because of its high specific capacity, it is considered one of the most promising candidates to replace the conventional graphite negative electrode used in today's Li ion batteries. Silicon has a theoretical specific capacity of nearly 4200 mAh/g (Li21Si5), which is 10 times larger than the specifi...
Article
Rechargeable lithium metal batteries are considered the "holy grail" of energy storage systems. Unfortunately, uncontrollable dendritic lithium growth inherent in these batteries (upon repeated charge/discharge cycling) has pre-vented their practical application over the past 40 years. We show a novel mechanism which can fundamentally alter dendrit...
Article
Large-scale electrical energy storage has become more important than ever for reducing fossil energy consumption in transportation and for the widespread deployment of intermittent renewable energy in electric grid. However, significant challenges exist for its applications. Here, the status and challenges are reviewed from the perspective of mater...
Article
Full-text available
High voltage spinel LiNi(0.5)Mn(1.5)O(4) is a very promising cathode material for lithium ion batteries that can be used to power hybrid electrical vehicles (HEVs). Through careful control of the cooling rate after high temperature calcination, LiNi(0.5)Mn(1.5)O(4) spinels with different disordered phase and/or Mn(3+) contents have been synthesized...
Article
A cost-effective and scalable method is developed to prepare a core-shell structured Si/B(4)C composite with graphite coating with high efficiency, exceptional rate performance, and long-term stability. In this material, conductive B(4)C with a high Mohs hardness serves not only as micro/nano-millers in the ball-milling process to break down micron...
Article
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The complex correlation between Mn(3+) ions and the disordered phase in the lattice structure of high voltage spinel, and its effect on the charge transport properties, are revealed through a combination of experimental study and computer simulations. Superior cycling stability is achieved in LiNi(0.45)Cr(0.05)Mn(1.5)O(4) with carefully controlled...
Article
Full-text available
Two organic cathode materials based on the poly(anthraquinonyl sulfide) structure with different substitution positions were synthesized and their electrochemical behavior and battery performance were investigated. The substitution positions on the anthraquinone structure, the type of binders for electrode preparation, and electrolyte formulations...
Article
Proton conducting polymer composite membranes are of technological interest in many energy devices such as fuel cells and redox flow batteries. In particular, polymer composite membranes, such as SiO(2) incorporated Nafion membranes, are recently reported as highly promising for the use in redox flow batteries. However, there is conflicting reports...
Article
Full-text available
The lithium-air battery is one of the most promising technologies among various electrochemical energy storage systems. We demonstrate that a novel air electrode consisting of an unusual hierarchical arrangement of functionalized graphene sheets (with no catalyst) delivers an exceptionally high capacity of 15000 mAh/g in lithium-O(2) batteries whic...
Article
Full-text available
Electrochemically active LiMnPO4 nanoplate at lithiated/delithiated state were subjected to thermal stability and phase transformation evaluate for safety as a cathode material for Li-ion battery. The phase transformation and oxygen evolution temperature on the delithiated MnPO4 were characterized using in-situ hot-stage X-ray diffraction (XRD), X-...
Article
Full-text available
In this paper, the influences of the lithium content in the starting materials on the final performances of as-prepared Li(x)MnPO(4) (x hereafter represents the starting Li content in the synthesis step which does not necessarily mean that Li(x)MnPO(4) is a single phase solid solution in this work.) are systematically investigated. It has been reve...
Article
Low cost, high performance redox flow batteries are highly demanded for up to multi-megawatt levels of renewable and grid energy storage. Here, we report a new vanadium redox flow battery with a significant improvement over the current technologies. This new battery utilizes a sulfate-chloride mixed solution, which is capable of dissolving more tha...
Article
Though considered a promising large-scale storage device for regulating renewable energy supply during calm and cloudy weather, the vana-dium redox battery's use has been limited by its inability to work well in a wide range of temperatures and its low energy density. Adding hydro-chloric acid to the sulfuric acid electrolyte typically used in vana...
Article
The V5+ electrolyte solution from Vanadium Redox Flow Batteries was studied by variable temperature 17O and 51V Nuclear Magnetic Resonance (NMR) spectroscopy and density functional theory (DFT) based computational modeling. It was found that the V5+ species exist as hydrated penta co-ordinated vanadate ion, i.e. [VO2(H2O)3]1+. This hydrated structu...
Article
Synthesis of the spinel lithium titanate Li4Ti5O12 by an alkoxide-free sol–gel method is described. This method yields highly pure and crystalline Li4Ti5O12 samples at relatively low temperature (850 °C) and via short thermal treatment (2 h). 6Li magic angle spinning nuclear magnetic resonance (MAS NMR) measurements on these samples were carried ou...
Article
In this paper, we report the electrochemical characteristics of a novel cathode material, Li2CoPO4F, prepared by solid-state reactions. The solid-state reaction mechanism involved in synthesizing the Li2CoPO4F also is analyzed in this paper. When cycled between 2.0V and 5.0V during cyclic voltammetry measurements, the Li2CoPO4F samples present one,...
Article
The Nation membrane is a critical component in redox flow batteries, which are widely investigated for grid-scale energy storage. However, there is very limited understanding of the fundamental properties of the membrane materials in the working environment relevant to redox flow batteries. This paper presents results of the analysis of the Nafion-...
Article
The vanadium(IV) electrolyte solutions with various vanadium concentrations are studied by variable temperature H-1 and O-17 nuclear magnetic resonance (NMR) spectroscopy. The structure and kinetics of vanadium(IV) species in the electrolyte solutions are explored with respect to vanadium concentration and temperature. It was found that the vanadiu...
Article
Full-text available
The electrochemical performances of anode consisting of micron-sized Si particles are stabilized by a two-step process. First, the electronic conductivity of the individual silicon particle is enhanced by a uniform carbon coating on its surface and inside the pores via chemical vapor deposition (CVD) process. The deposited amorphous carbon from CVD...
Article
Full-text available
Electrochemically active LiMnPO(4) nanoplates have been synthesized via a novel, single-step, solid-state reaction in molten hydrocarbon. The olivine-structured LiMnPO(4) nanoplates with a thickness of approximately 50 nm appear porous and were formed as nanocrystals were assembled and grew into nanorods along the [010] direction in the (100) plane...
Article
Thin film samples of CeCl3, CeBr3, and combinatorial compositions along the CeCl3–CeBr3 join were produced using thermal evaporation, which is being evaluated as a method for rapid screening of scintillator materials. The combinatorial thin films were shown to be compositionally reproducible from run-to-run within reasonable limitations. Analytical...
Article
Silicon-based nanowires have been grown from commercial silicon powders under conditions with different oxygen and carbon activities. Nanowires grown in the presence of carbon sources consisted of a crystalline SiC core with an amorphous SiOx shell. The thickness of the SiOx shell decreased as the oxygen concentration in the precursor gases decreas...
Article
Li-ion batteries made from LiFePO4 cathode and anatase TiO2/graphene composite anode were investigated for potential application in stationary energy storage. Fine-structured LiFePO4 was synthesized by a novel molten surfactant approach whereas anatase TiO2/graphene nanocomposite was prepared via self-assembly method. The full cell that operated at...
Article
Surfactant or polymer directed self-assembly has been widely investigated to prepare nanostructured metal oxides, semiconductors, and polymers, but this approach is mostly limited to two-phase materials, organic/inorganic hybrids, and nanoparticle or polymer-based nanocomposites. Self-assembled nanostructures from more complex, multiscale, and mult...
Article
Understanding lithium diffusion properties in electrode materials is important for designing rechargeable lithium-ion batteries with improved performance. In this work, the lithium dynamics in layered Li2TiO3 were characterized using a combination of 6,7Li nuclear magnetic resonance (NMR) over a wide temperature range (150−500 K) and molecular dyna...
Article
Rutile TiO2 nanorods were synthesized by hydrolysis of TiCl4 followed by a hydrothermal method. Lithium insertion into the rutile nanorods was achieved by a chemical lithium intercalation process. The structural evolution of nano-structured rutile upon lithium intercalation was characterized by several experimental techniques, namely, XRD, TEM and...
Article
Being inherently safe and chemically compatible with the electrolyte, titanium oxide-based materials, including both Li-titanites and various TiO2 polymorphs, are considered alternatives to carbonaceous anodes in Li-ion batteries. Given the commercial success of the spinel lithium titanites, TiO2 polymorphs, in particular in nanostructured forms, h...
Article
Full-text available
Rutile TiO 2 nanorods were synthesized by hydrolysis of TiCl 4 followed by a hydrothermal method. Lithium insertion into the rutile nanorods was achieved by a chemical lithium insertion process. The structural evolution of nanostructured rutile upon lithium insertion was characterized by several experimental techniques, namely, XRD, TEM, SAED and 6...
Article
Thin-film solar cells based on CIGS are being considered for large scale power plants as well as building integrated photovoltaic (BIPV) applications. Past studies indicate that CIGS cells degrade rapidly when exposed to moisture. As a result, an effective approach to encapsulation is required for CIGS cells to satisfy the international standard IE...
Article
Recently, the role of nanostructured materials in addressing the challenges in energy and natural resources has attracted wide attention. In particular, oriented nanostructures demonstrate promising properties for energy harvesting, conversion, and storage. In this Review, we highlight the synthesis and application of oriented nanostructures in a f...
Article
Multilayer polymer/oxide coatings are being developed to protect sensitive organic display devices, such as OLEDs, from oxygen and water vapor permeation. The coatings have permeation levels ~ 10-6 g/m2/d for water vapor and ~10-6 cc/m2/d for oxygen, and are deposited by vacuum polymer technology. The coatings consist of either a base Al2O3 or acry...
Article
Titanium oxide (TiO2) thin films have been deposited on silicon, glass, and plastic substrates by destabilization of an aqueous titanium lactate solution at low temperatures (<100°C). The process uses a commercially available, low-cost precursor and is simple to perform; it involves only control of pH in aqueous, chelated titanium solutions. With t...
Article
Multilayer, thin-film organic/inorganic composite barrier layers have recently been reported to achieve water vapor permeation rates of <10−5 g∕m2∕day at 25 °C∕40%RH on polyethylene terephthalate substrates. Using both transient and steady-state vapor permeation measurements combined with classical Fickian diffusion models, we determine the mechani...
Article
Thin film barrier coatings for protecting Organic Light Emitting Diode (OLED) displays against the environment are extremely difficult to fabricate. The coatings must have extremely low water/oxygen permeability, no defects, cover several microns of topography, and be applied at temperatures below 100°C in a process that does not compromise the per...
Article
A method for conformally coating a microtextured surface. The method includes flash evaporating a polymer precursor forming an evaporate, passing the evaporate to a glow discharge electrode creating a glow discharge polymer precursor plasma from the evaporate, cryocondensing the glow discharge polymer precursor plasma on the microtextured surface a...
Article
Multilayer organic/inorganic structures are being developed for use as ultrabarrier protective coatings for thin-film electronic applications. These barrier coatings are used to directly encapsulate the electronic device to improve lifetime and performance, and are expected to replace existing parylene, epoxy, and other single layer inorganic metho...
Article
Traditional single layer barrier coatings are not adequate in preventing degradation of the performance of organic molecular electronic and other active devices. Most advanced devices used in display technology now consist of micro and nanostructured small molecule, polymer and inorganic coatings with thin, high reactive group 1A metals. This inclu...
Article
A method of making a composite polymer of a molecularly doped polymer. The method includes mixing a liquid polymer precursor with molecular dopant forming a molecularly doped polymer precursor mixture. The molecularly doped polymer precursor mixture is flash evaporated forming a composite vapor. The composite vapor is cryocondensed on a cool substr...
Article
We fabricate long-lived organic light-emitting devices using a 175 μm thick polyethylene terephthalate substrate coated with an organic–inorganic multilayered barrier film and compare the rate of degradation to glass-based devices. The observed permeation rate of water vapor through the plastic substrate was estimated to be 2×10−6 g/m2/day. Driven...
Article
Organic light emitting diodes (OLEDs) have recently entered the market place as a competitive flat panel display technology. OLED displays are moving rapidly from small passive matrices (i.e. <3" diagonal) to full color active matrices based on rigid substrates. This paper is focused on new developments to help enable flexible OLED (FOLED) displays...
Article
An encapsulated organic light emitting device. The device includes a first barrier stack comprising at least one first barrier layer and at least one first polymer layer. There is an organic light emitting layer stack adjacent to the first barrier stack. A second barrier stack is adjacent to the organic light emitting layer stack. The second barrie...
Article
We describe a flexible, transparent plastic substrate for flat panel display applications. Using roll-coating techniques, we apply a composite thin film barrier to commercially available polymers, which restricts moisture and oxygen permeation to undetectable levels using conventional permeation test equipment. The barrier film can be capped with a...
Article
We describe a flexible, transparent plastic substrate for OLED display applications. A flexible, composite thin film barrier is deposited under vacuum onto commercially available polymers, restricting moisture and oxygen permeation rates to undetectable levels using conventional permeation test equipment. The barrier is deposited under vacuum in a...
Article
The calcium test was used to evaluate high performance diffusion barriers. A permeation method was presented in order to evaluate flexible plastic substrates for organic electroluminescent light emitting displays (OLED) applications. The method, which is based the corrosion of reactive metal films, was used to quantify the water transmission rate o...
Article
The technology of organic light emitting devices (OLEDs) has recently demonstrated excellent performance for use in flat panel display (FPD) applications. OLED displays emit bright, colorful light with excellent power efficiency, wide viewing angle and video response rates; OLEDs are also demonstrating the requisite environmental robustness for a w...
Conference Paper
Protective ultrabarrier coatings for displays on flexible polymeric film substrates were deposited. The ultrabarrier coatings met a number of tight performance specifications including low gas permeation, high conductivity transparent electrodes, chemical resistance, thermal stability and scratch resistance must be met. Transmission of oxygen and w...
Article
The surface modification of poly(ethylene terephthalate) (PET) and UV-cured tripropyleneglycol diacrylate (acrylic) films induced by remote N2 and Ar microwave plasmas (2.45 GHz) was compared by in-situ XPS measurements. Both N2 and Ar plasma treatments led to destruction of the initial oxygen-containing groups. The destruction of ester groups was...
Article
Millions of gallons of the United States' existing inventory of radioactive wastes need to be converted into stable waste forms for long term disposal. Unfortunately, liquid wastes can contain agglomerates of insoluble particles that interfere with retrieval, transport, separation and solidification procedures. Some particulate suspensions form vis...
Article
A new process has been developed for the high rate vacuum deposition of solid films from high molecular weight/low vapor pressure liquid, or even solid, monomer precursors. The gas resulting from the flash evaporation of a liquid monomer mixture or from a suspension of liquid monomer and insoluble solid particles is used as the support medium for a...
Article
Residual gas analysis (RGA) and optical emission spectroscopy have been evaluated as potential in situ techniques for the detection of plasma-induced polymer surface etching. The detection is based on the measurement of CO and CO2 species formed in the gas phase following oxidation of the etching fragments released from the polymer surface. Experim...
Article
Full-text available
Disposal of millions of gallons of existing radioactive wastes in underground storage tanks is a major remediation activity for the United States Department of Energy. These wastes include a substantial volume of insoluble sludges consisting of submicron colloidal particles. Processing these sludges under the proposed processing conditions presents...
Article
A freeform fabrication method for ceramic components using selected-area-gelation of slurry layers is used to produce high-density alumina components with fine-grained microstructures and flexural strengths exceeding 400 MPa. The results obtained are described and the potential of the approach is discussed.
Article
Millions of gallons of radioactive wastes stored at Department of Energy sites need to be converted into stable waste forms for long term disposal. Unfortunately, many of the wastes contain colloidal sludges that can interfere with retrieval, transport, separation, and solidification procedures. The ability to predict and control the behavior of sl...
Article
The invention provides a method for synthesizing a titanium oxide-containing film comprising the following steps: (a) preparing an aqueous solution of a titanium chelate with a titanium molarity in the range of 0.01M to 0.6M. (b) immersing a substrate in the prepared solution, (c) decomposing the titanium chelate to deposit a film on the substrate....
Article
A new process has been developed for the high rate vacuum deposition of solid films from high molecular weight/low vapor pressure liquid, or even liquid/solid suspension, monomer precursors. The gas resulting from the flash evaporation of a liquid monomer mixture, or from a suspension of insoluble solid particles in liquid monomer, is used as the s...
Article
Polymer/oxide/polymer barrier coatings have been fabricated on 50 μm thick and 100 μm thick polyethylene terephthalate (PET) substrate in a roll-to-roll coating process. The oxide layer was either sputtered or e-beam evaporated Al2O3 and the polymer layers were deposited by the polymer multilayer (PML) method and . The monomer curing method employe...