Department of Chemistry

Novel Electrolytes for Rechargeable Alkali Batteries

Investigator(s)	Angell, C.A.; Xu, K.			$137,000
Phone	602-965-7217
E-mail	caa@asu.edu

An extension of our original program on "ionic rubber electrolytes" is in progress. The ion-plasticized salt/polymer complex, which constitutes the ionic rubber, is being further plasticized by additives of various types to explore a wide range of possible high conductivity, high cation transport number, rubbery electrolytes. Additives under study are inorganic quasi-salts, which are resistant to attack by Li and are stable to one volt negative with respect to Li⁺/Li, boroxy-based Lewis acid molecular solvents, which solvate anions and form Li⁺-conducting protective films on lithium metal, and inorganic molecular liquids. Some of these systems are suitable for rechargeable Li cell construction. New polymers which are compatible with Li chloroaluminates are being sought.

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Department of Materials Science

Design of Metal Hydride Alloys for Battery Electrodes with High Cycle Lifetimes

Investigator(s)	Fultz, B.; Ratnakumar, B.V.			$175,451
Phone	818-395-2170
E-mail	btf@hyperfine.caltech.edu

This program is addressing basic questions that underlie the design of new metal hydride alloys for service as negative electrodes in nickel - metal hydride battery cells. Ternary solutes from the groups IIIB, IVB, VB of the periodic table are being substituted for Ni in LaNi₅ in a systematic way and in dilute amounts to preserve the single-phase CaCu₅ -type crystal structure. We are correlating the thermochemical properties of the solute atoms to their effects on the cyclic lifetime of the metal hydride electrodes, both during electrochemical cycling and during gas-phase cycling. The microstructural changes resulting from the degradation processes of the electrodes are being analyzed by x-ray diffractometry and transmission electron microscopy. Effects of temperature and electrical parameters during charge/discharge cycling are also being used to test ideas about the mechanisms of electrode deterioration. Additional studies of engineering importance for metal hydride electrodes include measurements of thermodynamic and kinetic properties of hydrogen absorption in different alloys.

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Chemistry Department

Applications of In-Situ and Ex-Situ Spectroscopic Techniques for the Study of Electrode Materials with Relevance to Energy Generation and Energy Storage

Investigator(s)	Scherson, D.A.			$149,999
Phone	216-368-3620
E-mail	dxs16@po.cwru.edu

Electronic and structural aspects of a MnO₂ electrode in a rechargeable MnO₂/Zn battery have been examined in situ as a function of the state of charge by Mn K-edge X-ray absorption fine structure (XAFS). All data were acquired in a sandwich-type spectroelectrochemical cell which employs the same electrode materials found in commercial MnO₂/Zn rechargeable batteries. The main conclusions emerging from this study may be summarized as follows: (i) The relative amplitudes of the three major Fourier transform shells of the extended X-ray absorption fine structure (EXAFS) function of the MnO₂ electrode in the undischarged state are very similar to those found for ramsdellite, a MnO₂ polymorph with substantial corner-sharing linkages among the basic MnO₆ units. (ii) An analysis of the background-subtracted pre-edge peaks and absorption edge regions for the net 1-e^- discharged electrode yielded Mn³⁺ as the predominant product. (iii) An analysis of the spectral data revealed that the full recharge of MnO₂, which had been previously discharged either by 1-e^- or 2-e^--equivalent electrons, generates a material with decreased corner-sharing linkages compared to the original undischarged MnO₂. Insight into the nature of the species generated by the discharge and recharge of pyrite (FeS₂) in non-aqueous electrolyte was gained from the analysis of XAFS data recorded in situ. Measurements were obtained using a carefully designed sandwich-type FeS₂/Li spectroelectrochemical cell consisting of a thin film (1.5 mil) of LiClO₄-doped poly(ethylene oxide) (PEO) solid polymer electrolyte, an FeS₂ cathode formed by spreading finely ground, naturally occurring pyrite directly onto the polymer electrolyte, using a gold sputtered Ni foil as the current collector, and a lithium strip placed on the other side of the electrolyte serving as a counter-reference [C/R] electrode. The analysis of the in situ extended X-ray absorption fine structure (EXAFS) yielded an Fe-S distance for a cell which had been first fully 4-e^- discharged, and, subsequently, 2-e^- recharged, remarkably similar to that found for pyrite. Furthermore, the features observed in the X-ray absorption near edge region (XANES) were similar to species in which the iron is present in a tetrahedral environment. Both these findings are not consistent with Li₂FeS₂ as being present in these electrodes, as has been proposed in the literature.

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Department of Chemistry

Novel Aluminum and Sulfur Batteries

Investigator(s)	Licht, S.
Phone	508-793-7112
E-mail	SLICHT@VAX.CLARKU.EDU

Work is actively proceeding on development of a new battery, the aluminum sulfur battery. Each storage cell contains an aluminum anode, a solid sulfur, and/or aqueous polysulfide cathode and operates at or near room temperatures. Both the very high discharge domain (over 10 mA/cm²) and the low discharge domain (less than 0.1 mA/cm²) of the cell are being studied and optimized. Development includes optimization of the aluminum anode and of the sulfur cathode through electrochemical, spectroscopic, and potentiometric measurements in a variety of temperature, concentration, and partial discharge domains for the combined solid sulfur-aqueous polysulfide system. Measurements of aluminate, hydroxide, and solution additive concentrations during anode discharge are being studied to improve anodic utilization efficiencies under a variety of discharge conditions. Cells incorporating the most promising modifications are being tested. From these discharge tests, high energy capacity cells will be designed and tested with a 250-Wh/kg objective.

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Department of Chemistry

Nanomaterials in Secondary Battery Research and Development

Investigator(s)	Martin, C.R.			$80,000 (15 months)
Phone	970-491-0271
E-mail	crmartin@lamar.colostate.edu

Li-ion batteries are one of the most promising technologies for the development of a new generation of high energy-density, light weight portable power sources. For this reason a substantial research effort is currently being devoted to development of new electrode materials and electrolytes for such batteries. Surprisingly, however, very little work is being devoted to optimization of the electrode morphology - specifically optimal particle shape and size for the Li-insertion material that makes up the battery electrode. The reason this area has been neglected is that, prior to our work, there have been essential no methods that allow for synthesis of Li-insertion materials with tailored particle sizes and shapes. We have developed a novel approach for preparing monodisperse nanoscopic particles of nearly any desired material. This method, called "template synthesis" produces nanoscopic tubules and fibers of the desired material. The objective of this work is to use the template approach to prepare high density ensembles of tubular and fibrilar Li-insertion materials and then to show that these nano-engineered battery electrodes can out-perform electrodes, of the same material, that have been prepared via conventional routes. In particular, we would like to show that the nano-engineered tubular and fibrilar battery electrodes can deliver higher capacity, at high discharge currents, than conventional battery electrodes. We have already proven that this concept works. In collaboration with Professor Hiroshi Yoneyama at Osaka University, we prepared nanoscopic tubules of the cathode material LiMn₂O₄. A high density ensemble of tubules in which the tubules protruded from a substrate current collector surface like the bristles of a brush was prepared. The tubules had an outside diameter of 200 nm and a wall thickness of ca. 50 nm. Constant current charge and discharge experiments were conducted on these tubular electrodes and on a conventional thin film electrode composed of the same material. Both the tubular and thin film electrodes contained 0.75 mg of LiMn₂O₄ per cm² of Pt current-collector surface area. We found that the tubular electrode delivered greater capacity than the thin film electrode and that the ratio of the tubule capacity to the thin film capacity increased with increasing current density. At a current density of 1.0 mA per cm², the tubular electrode delivered an order of magnitude higher capacity than the thin film electrode, even though both electrodes contained the same amount of LiMn₂O₄.

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Corrosion Research Center

Characterization of Insertion Electrodes in High-Energy Cell

Investigator(s)	Smyrl, W.H.			$275,625 (15 months)
Phone	612-625-0717
E-mail	smyrl001@maroon.tc.umn.edu

The objective of the research is to perform the enabling materials research necessary for the development of a battery oriented to the consumer market. Special requirements, in terms of safety, cycling life, and high energy and power densities are necessary for this class of batteries. The discovery in our laboratory of a novel V₂O₅ material that has a high capacity for Mg⁺² insertion (4 equivalents of Mg⁺² per mole of V₂O₅) opens the way for its use as a 'universal' host for intercalation of divalent and trivalent cations. Magnesium, zinc, and aluminum are being studied because of their high energy, combined with their availability, low-cost, and increased safety over lithium-based systems. With the introduction of the lithium-ion concept that avoids the problem of safety hazards of lithium metal anode batteries, the area of nonaqueous high-energy, rechargeable batteries offers promise for portable consumer products. A second approach is to develop battery systems of other energetic materials. The present research is directed to the synthesis of high-capacity, reversible aerogels of V₂O₅ materials for Mg⁺², Zn⁺², and Al⁺³ battery systems.

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School of Physics and Astronomy

Modeling of Transport in Lithium Polymer Electrolytes for Battery Applications

Investigator(s)	Halley, J.W.			$100,302 (15 months)
Phone	612-624-0395
E-mail	woods@jwhp.spa.umn.edu

The goal of this research is to provide new insight into the mechanism of ionic conduction in Li polymer electrolytes and the electrolyte-electrode interface using a combination of new and powerful simulation techniques that have not previously been applied to these materials. A molecular dynamics model for amorphous polyethylene oxide has been developed, using a unique approach in which the model is developed by simulating a polymerization process, starting with liquid dimethyl ether. This has significant advantages over starting a molecular dynamics simulation in the crystalline phase. We are using the molecular dynamics model to evaluate solvation and hopping activation free energies for Li⁺ ions and various cations. This output from the molecular dynamics studies will be used to construct lattice models of the system at larger length and longer time scales appropriate to the transport problem and to evaluate various suggestions concerning the nature of the ionic transport in these electrolytes. Later, the models will also be used to study the electrode-electrolyte interface.

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New Materials Technology For Rechargeable Lithium Batteries

Investigator(s)	Skotheim, T.			$143,000
Phone	520-799-7500
E-mail	skotheim@moltech.com

Rechargeable batteries with high specific energy are of critical importance for applications where portability is an issue. The objective of this program is to develop significantly improved polymer technology that will be incorporated into thin film rechargeable lithium cells, which have the potential to leapfrog existing technologies. We are currently developing advanced battery technologies and materials for high-capacity, long-cycle-life lithium polymer batteries. Our work on high-capacity organo-sulfur polymer cathode materials has made significant progress, including synthesis and characterization of all materials made in-house. Processing techniques for polymer cathode are being determined and/or improved, resulting in better performance of our laboratory test cells.

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Department of Physics

Long-Ranged Polymer Dynamic Behavior and Conductivity in Battery Polymer Electrolytes: Poly(ethylene oxide)/Salt Systems

Investigator(s)	Selser, J.C.			$20,000
Phone	702-895-3847
E-mail	selser@physics.unlv.edu

In this project, light scattering - principally the noninvasive dynamic light scattering technique known as photon correlation spectroscopy - is being used to study long-ranged, slow relaxations of poly(ethylene oxide) (PEO) in methanol solutions and in the melt both with and without lithium perchlorate. The purpose of this work is to reveal how long-ranged PEO relaxations in PEO solid polymer electrolytes are related to lithium ion conductivity in these electrolyte systems. Following the project plan outlined in the FY 1995 project summary, the first phase study of the effects of lithium ions on PEO global behavior in methanol solutions has been completed and the results reported in the literature (P.A. Banka, et al, Macromolecules 1996, 29, 3956-3959). Briefly, it was found that repulsive interactions between lithium ion/PEO oxygens complexes caused PEO coils to swell in solution resulting in the conversion of PEO to a polymer electrolyte and the "salting in" of PEO in methanol. Significantly, it was shown that repulsively interacting complexes were not uniformly distributed along PEO chains, but were instead concentrated in coil outer portions. The study of the effect of lithium ions on PEO coil internal motions is also progressing but completion of this portion of the project awaits delivery of a satisfactory high molecular weight, narrow molecular weight distribution PEO sample. Significant progress has also been made on the second phase of the project dealing with melt PEO samples. Development of a procedure for preparing optically clear melt samples is close to completion and light scattering measurement capability has been extended by the purchase of a second light scattering photometer, modification of the existing photometer, development of light scattering measurement methodology and on improved data analysis.

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Department of Physics and Astronomy

Magnetic Resonance and X-Ray Absorption Studies of Materials for Advanced Batteries

Investigator(s)	Greenbaum, S.G.; denBoer, M.L.			$202,000
Phone	212-772-4973
E-mail	sgreenbau@shiva.hunter.cuny.edu

A comprehensive three-year program of spectroscopic investigations of secondary lithium battery materials is proposed. All three components of cells under development for high energy density lithium ion batteries will be studied: lithiated carbon anodes, polymer electrolytes, and transition metal oxide cathodes. The proposed research will involve close interactions with Cambridge Battery Associates, Inc. (A subsidiary of Arthur D. Little, Inc.), E.I.C. Laboratories, Inc., and the U.S. Army Power Sources Laboratory (ARL), as well as other groups. The mode of collaboration includes provision of (electrochemically) well-characterized samples for our studies in return for spectroscopic feedback to be utilized in continued materials development and, of course, joint publications of scientific results. We propose ⁷Li nuclear magnetic resonance measurements to provide information on the local environment and dynamics of mobile Li⁺ in cathodes and electrolytes. Complementary information on the geometric and electronic environment of the transition metal ion will be obtained by x-ray absorption spectroscopy, both near-edge and extended fine structure, and corresponding soft x-ray absorption measurements of the C 1s level in the lithiated carbon. The x-ray measurements will be supplemented by electron paramagnetic resonance measurements, which yield knowledge of spin densities and symmetries. In situ x-ray absorption and synchrotron infrared techniques will also be developed and implemented.

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Department of Chemical Engineering

Composite Polymer Electrolytes Using Cross-Linked Fumed Silica Fillers in Low Molecular Weight Polyethylene Oxides: Synthesis, Rheology and Electrochemistry

Investigator(s)	Khan, S.A.; Fedkiw, P.S.; Baker, G.L.			$165,626
Phone	919-515-4519
E-mail	Khan@che.ncsu.edu

The objective of this project is the synthesis and evaluation of a composite polymer electrolyte system for use in rechargeable lithium batteries. Based on surface-modified, cross-linked fumed silica and low molecular weight polyethylene oxide/glycols, this new approach should yield low-cost, processable solid electrolytes with conductivities that rival gel electrolytes. The principal features of the new system include: (i) exceptional processability; the composite is processable as a viscous fluid using standard techniques but can set to give a solid with a yield point, (ii) dimensional stability; the fumed silica can be cross-linked by UV, thermal, or other curing methods to improve the mechanical properties and ensure dimensional stability, (iii) good conductivity; room temperature conductivities for electrolytes containing lithium salts should easily reach 5 x 10^-4S/cm, (iv) low cost; this is a consequence of simple processing and the ready accessibility of the materials, and (v) inherent safety; cured composite electrolytes should have the electrochemical stability typical of solid polymers. Current efforts have focused on the synthesis of surface-modified fumed silica and understanding the processing/rheological behavior of fumed silica composites. Two different types of surface-anchored groups have been attached to commercial fumed silica; these materials are being characterized to determine and optimize their surface coverage. Electrochemical and rheological studies have been undertaken on composite polymer electrolytes consisting of surface modified fumed silica with octyl groups, methyl-capped polyethylene glycol and lithium imide salts. Our results show these materials to exhibit room temperature ionic conductivities higher than 10^-3 S/cm and improved electrochemical stability. In addition, they exhibit mechanical strength with modulus similar to some elastomers, ~10⁶ dynes/cm². These properties, together with the processability ease of these systems, show great promise for fumed silica composite electrolytes.

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Center for Advanced Materials

Development of Novel Strategies for Enhancing the Cycle Life of Lithium Solid Polymer Electrolyte Batteries

Investigator(s)	Macdonald, D.D.; Allcock, H.R.; Urquidi-Macdonald, M.			$231,000
Phone	814-863-7772
E-mail	digby@essc.psu.edu

A wide range of substituted polyphosphazenes that can serve as the bases for solid polymer electrolytes (SPEs) have been synthesized during the past three years of the project. The conductivities of SPEs formed from these polyphosphazenes and lithium triflate (LiSO₃CF₃) have been measured, and many are found to be greater than 10^-5S/cm at 25°C. Most importantly, we have established correlations between the substituent properties and the conductivity that will guide future synthetic efforts. We have also paid attention to the rhehological properties of the polymers, with the goal of identifying systems that would not require crosslinking, because this adds an additional step in any manufacturing process and hence increases the cost. Finally, we have fabricated prototype batteries of the type Li/SPE/TiS₂, which are found to have open circuit voltages of 2.8 - 3.02V, but in-depth performance studies have yet to be performed. In parallel with the synthetic work outlined above, we have developed a combined impedance/dilatometry system for exploring the cycling performances of laminates that have been fabricated using the substituted polyphosphazenes. By using the Pt/SPE/Pt laminate, we have shown that the impedance of the system can be delineated into interfacial and bulk electrolyte components, as determined from the effect of pressure. Increasing pressure is found to decrease the interfacial resistance but to increase the bulk resistivity, with the latter being attributed to a decrease in the free volume. The cycling behavior of Li/SPE/Li has also been explored, in terms of changes in impedance and laminate thickness, as lithium (6 mA. hrs) is electrochemically pumped from one side to the other. We find no degradation (increase) in the impedance as the system is cycled at a current density of 6 mA/cm² for more than 500 cycles. This finding suggests that, although irreversible changes occur at the Li/SPE interface, and perhaps in the bulk electrolyte as well, the metallic lithium/SPE interface should not be the limiting factor in cycle life performance, at least for laminates based on substituted phosphazenes. This is in contrast to other SPEs, where lithium "powdering" has been implicated in a sudden increase in cell (Li/SPE/IC) resistance and hence to failure. Finally, based on our impedance studies, we have derived physical models for the interface, including an electrical analog and a model based on the interstitial conduction of Li⁺ through a reaction product layer at the Li/SPE interface. We have also developed an Artificial Neural Network (ANN) model for Li/SPE/IC batteries, based on data taken from the literature. This model shows that the charge/discharge rate and depth of discharge, amongst other factors, are important parameters in determining cycle life.

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College of Engineering

Solid Electrolyte-Electrode Interfaces: Atomistic Behavior Analyzed Via UHV-AFM, Surface Spectroscopies, and Computer Simulations

Investigator(s)	Garofalini, S.H.			$112,750 (15 months)
Phone	908-445-2216
E-mail	shg@rutile.rutgers.edu

UHV-AFM, STM, and XPS surface analyses and molecular dynamics computer simulations have been used to examine the structural and dynamic properties of the cathode/electrolyte interface in solid-state oxide thin-film batteries. In the experiments, the electrolytes have included lithium-containing borates, phosphates, and phosphorous oxynitride ion conducting (IC) glasses and Li and V₂O₅ as the cathode/electrode materials. Lithium silicates and WO₃ and V₂O₅ have been studied in the simulations. Lithium migration into the oxide cathode during formation of the interface between the cathode and the IC oxide glasses has been evaluated using XPS and the simulations. Results show significant lithium migration across the interface during interface formation in both the experiments and the simulations. In the XPS studies, V₂O₅ was deposited in situ onto lithium borate, lithium phosphate, and lithium phosphorous oxy-nitride glass substrates using RF sputtering. The thickness of the IC glass substrates was varied from 50Å to 750Å. The Li concentration in the cathode was measured as a function of cathode overlayer thickness on each glass electrolyte. A correlation between electrolyte thickness and Li penetration in to the cathode was observed. However, this migration could be controlled under appropriate conditions. In the molecular dynamics simulations, new potentials were generated to give stable crystalline forms of vanadia and tungsten oxide and -lithium vanadate and lithium tungsten bronze. Valence change of the cathode cations as a function of Li intercalation was employed to mimic the real situation. The simulations showed penetration of Li from the IC glass into the cathode, with different penetration occurring as a function of crystal orientation. The amorphous form of the cathode also behaved differently than the crystalline forms, consistent with experimental data. Importantly, Li intercalation from the glass electrolyte into the vanadia showed the appropriate phase change to the form of lithium vanadate, even though the potentials were not designed for this phase. This shows the robustness of the potentials used here. Also, a channeling of Li occurred in the glass in contact with the WO₃ crystal as the Li migrated into the crystal. Finally, UHV-AFM force distance studies using a lithiated electrolyte glass and an oxidized tungsten tip indicated the ability of using this approach to determine transport characteristics on a nanometer scale.

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Department of Chemical Engineering

Synthesis, Characterization, and Testing of Novel Anode and Cathode Materials for Li-Ion Batteries

Investigator(s)	White, R.E.; Popov, B.N.; Ritter, J.A.			$200,000
Phone	803-777-3270
E-mail	rew@sun.che.sc.edu

The primary objectives of this proposed research are to synthesize and characterize novel compounds with high energy density and cycle life to be used as the cathode and anode materials in Li-ion cells with the following characteristics: (i) high reversibility of the Li-ion insertion/deinsertion reaction, (ii) high thermal stability and chemical compatibility of the electrodes with the electrolyte, (iii) good electronic conductivity of the electrodes, and (iv) high diffusivity of the Li-ion in the solid, active portion of the electrodes. These compounds will have higher capacities and energy densities than the materials that are used currently for Li-ion cells. In addition, the objectives include developing the ability to control and ultimately predict the microstructure of these cathode and anode materials by tailoring the chemistry and engineering history of the material, and to relate the macroscopic performance of the material to its microstructure (i.e., to develop structure-property relationships). The ultimate objective of this work is to use a priori knowledge to engineer the microstructure of a material to achieve optimal performance of a Li-ion battery.

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Center for Electrochemical Systems and Hydrogen Research

Cell Components with Emphasis on Hydride Electrolytes for Nickel/Metal Hydride Batteries

Investigator(s)	Srinivasan, S.			$118,500
Phone	409-845-8281
E-mail	b-mahan@tamu.edu

Hydride electrodes, using active materials prepared by mixing AB₅ and AB₂ (1:1) alloys, show better rate capabilities and cycle life behavior than electrodes using the individual alloys as active materials - mainly due to the higher chemical stability of the mixed alloys. The detailed mechanisms responsible for this better behavior are the subject of our on-going investigations. Addition of Zn or Pd to the metal hydride alloy decreases the capacity fading rate of the hydride electrode. Zinc addition to the electrolyte seems to be more advantageous than its inclusion in the alloy because in the former case, Zn is regenerated on the surface during charging of the electrodes. The changes in morphology, structure and composition of metal hydride electrodes, after charge/discharge cycles, were determined using scanning electron microscopy and energy dispersive X-ray analysis techniques. Capacity degradation after charge/discharge cycling and rate capability measurements of the hydride electrodes were also evaluated and correlated with these characteristics. Results showed that Al in an alloy enriches on the surface of alloy particles and causes its dissolution. Such a break-down of alloy particles enhances the electrode kinetics of the hydriding reaction and hence the rate capability of the hydride electrode.

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Electro-Optics Technology Center

Reseach on Advanced Thin Film Batteries

Investigator(s)	Goldner, R.B.			$20,000
Phone	617-627-3136
E-mail	rgoldner@pearl.tufts.edu

Affordable, high energy and power density rechargeable batteries are needed for powering portable electrical and electronic equipment for medical and consumer applications; and they are needed also for electrical vehicle and power load levelling applications. Most of the applications require voltages >3 Volts. Inorganic thin film lithium-ion rocking-chair cells are particularly attractive candidates for these batteries. To assist U.S. industry in their development of such advanced batteries, the Tufts University Electro-Optics Technology Center, (in collaboration with the Eveready Battery Company, Oak Ridge National Laboratory, Physical Sciences Inc., and Rome Air Force Laboratory), proposes to continue a research program the objective of which is to obtain affordable and safe prototype inorganic thin film lithium-ion rocking-chair batteries that are: more durable, have higher voltages, and higher power and energy densities than can be obtained with commercially available rechargeable batteries.

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Department of Chemistry and Biochemistry

The Development of Conductive Diamond Thin Films as Advanced Battery Electrode Materials

Investigator(s)	Swain, G.M.			$55,000 (15 months)
Phone	801-797-1626
E-mail	gmswain@cc.usu.edu

Synthetic diamond thin films possess several technologically useful properties including high chemical and thermal stability, excellent thermal conductivity, hardness, light weight and good electrical conductivity (doped form). One relatively unstudied application of this advanced material is the use of diamond thin films as electrode materials for advanced battery systems. The research being conducted in this project is focused on the growth and characterization of boron-doped(100 ppm B/C) diamond thin film electrodes for use in advanced batteries. Specifically, the performance characteristics of conductive diamond thin films, used as a support for the alkaline nickel hydroxide redox system, is being electrochemically, spectroscopically and microscopically evaluated. The research is being conducted in three parts. First, the coating of diamond on planar Ni and high surface area Ni FIBREX supports is being studied using microwave-enhanced chemical vapor deposition (CVD) as a function of the growth conditions (C/H ratio, pressure, temperature and plasma power). The objective of this phase of the research is to develop the conditions required to coat a continuous and conductive film on Ni and Ni FIBREX; the latter is a commonly used battery electrode material. The resulting films are fully characterized by SEM, AFM, Raman microprobe spectroscopy, XRD and AES. Second, the corrosion resistance of boron-doped diamond thin films, grown on planar Si substrates, is being tested in strongly alkaline electrolytes similar to those used in commercial batteries (5 wt.% KOH). The corrosion studies are being performed as a function of the diamond film properties, the electrolyte composition, solution temperature and cycle number or exposure time using cyclic voltammetry and ac impedance analysis. Once the conditions to coat diamond on Ni and Ni FIBREX have been developed, then the corrosion studies will utilize these materials. Third, Ni(OH)₂ films are being deposited on boron-doped diamond thin films, grown on planar Si substrates, and the electrochemical performance of the active material/diamond substrate is being studied during multiple charge and discharge cycles in 15 wt.% KOH. The active material is being deposited cathodically from Ni(NO₃)₂ solutions mixed with 50:50 ethanol and water. A novel feature of this phase of the research is the extensive use of in situ STM and AFM to examine the structural and electronic properties of the active material/diamond electrodes during different states of charge and discharge. This novel research may lead to the development of more durable and stable battery electrode materials exhibiting improved electrode reaction kinetics, coulometric efficiency, and performance lifetimes for the redox reaction of interest.

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