Anode Thickness Research Articles

Corrosion Behavior of Anodized Pure Zinc in Sea Water

In the present work an electrochemical anodizations of pure Zn sheet result in the ZnO porous film structure in alkaline solution (15% ammonium florid) by using constant voltage technique at a range of (2-10) volt, for period time of 10 minutes at room temperature was studied . Atomic force microscope (AFM) used to investigate the topography and roughness of anodic film formed on the surface, it was found that the roughness of the anodic film is mainly depended on the anodizing voltage and its increase from 0.2 (as polished) to (2.9) nm after anodizing. Coating thickness also increases with an increase in voltage from 0 to 285 μm after anodizing. The corrosion behaviors of anodized and non-anodized of zinc specimens in sea water are obtained. The corrosion current density and corrosion rate are decreased with an increase in supplying voltage which increases anodic film thickness.

Engineered Porous Foam Electrodes - New Approaches to Dendrite-Free Anodes for Li-Metal Batteries

Dendrite formation is a well-known metallurgical phenomenon occurring as a result of several energy minimization processes including preferential growth during solidification or stress-related grain-boundary evolution(1, 2). The occurrence of dendritic structures in electrochemical cells however, occurs as a result of electrochemical stripping/plating steps involving nucleation and growth processes(3). In this work, engineered porous foams are demonstrated as stable electrodes with high coulombic efficiency and limited orthogonal growth of surface dendrites. This unique approach is used to address dendritic growth and volumetric changes associated with plating/deplating of large volumetric amounts of lithium to generate thick lithium metal anodes. Figure 1 depicts the foam morphology as well as displays the superior performance of the new engineered electrodes over 100 cycles where almost no drop in coulombic efficiency is observed at very high current densities of ~100 mA/cm2. This presentation will examine the mechanisms associated with fabrication and design of such engineered porous foam electrodes resulting in the depicted noteworthy stable cycling. Figure caption: Figure 1: (a) SEM image of porous foam electrodes (b) Lithium symmetric cell using commercial lithium foils showing the rapid drop in charge-discharge capacity; (c) New engineered lithium electrodes showing excellent coulombic efficiency.

(Invited) Lithium Metal Batteries Using 3D Ionic or Electronic Frameworks

I will discuss our recent progress on Li metal batteries using multilayer Garnet structures, including bilayer and trilayer frameworks. Results based on various cathode including S, oxygen and high voltage cathodes will be discussed. I will also discuss our results on garnet nanostructures including 3D printed garnet framework, garnet paper and garnet fabrics which function as ionic conductive frameworks to enable stable, high current cycling of thick Li metal anode. Flexible garnet nanofiber-polymer hybrid electrodes with a high tortuosity and excellent mechanical strength will also be discussed. In the end, I will discuss low-tortuosity Li metal anode guided by anisotropic wood-based carbon framework.

(Invited) HQ Characterisations Techniques for Li-Ion and Solid State Batteries

In these presentation, we will present the data and movies of several an operando techniques to study lithium ion and solid state batteries such in situ SEM, In situ TEM, in situ Raman spectroscopy , in situ X-ray diffraction and in situ UV visible. These studies help to understand several mechanism such volume expansion of anodes such lithium metal (20 %), Graphite (10 %), LTO (0 %) and another example the measurements of the thickness of anode, cathode and electrolyte during charge discharge. The mechanism of lithium dendrite was also study and details will be shown during this presentation.Bleand Lithium/solid polymer electrolyte (SPE)/sulfur cells were studied in operando by two techniques: Scanning Electron Microscope (SEM) and ultraviolet-visible absorption spectroscopy (UV-vis). During the operation of the cell, extensive polysulfide dissolution in the solid polymer electrolyte (cross-linked polyethylene oxide) leads to the formation of a catholyte. A clear micrograph of the thick passivation layer on the sulfur-rich anode and the decreased SPE thickness by cycling confirmed the failure mechanism; the capacity decays by reducing the amount of active material, and by contributing to a charge inhibiting mechanism called polysulfide shuttle. The formation of elemental sulfur is clearly visible in real time during the charge process beyond 2.3 V. The non-destructive in operando UV-vis study also shows the presence of characteristic absorption peaks evolving with cycling, demonstrating the accumulation of various polysulfide species, and the predominant formation of S4 2- and of S6 2- during discharge and charge, respectively. This finding implies that the charge and discharge reactions are not completely reversible and proceed along different pathways.

Geometric Design of Anode-Supported Micro-Tubular Solid Oxide Fuel Cells by Multiphysics Simulations

High volumetric power density (VPD) is the basis for the commercial success of micro-tubular solid oxide fuel cells (mtSOFCs). To find maximal VPD (MVPD) for anode-supported mtSOFC (as-mtSOFC), the effects of geometric parameters on VPD are analyzed and the anode thickness, tan, and the cathode length, lca, are identified as the key design parameters. Thermo-fluid electrochemical models were built to examine the dependence of the electrical output on the cell parameters. The multiphysics model is validated by reproducing the experimental I-V curves with no adjustable parameters. The optimal lca and the corresponding MVPDs are then determined by the multiphysics model for 20 combinations of rin, the inner tube radius, and tan. And all these optimization are made at 1073.15 K. The results show that: (i) significant performance improvement may be achieved by geometry optimization, (ii) the seemingly high MVPD of 11 and 14 W/cm3 can be easily realized for as-mtSOFC with single- and double-terminal anode current collection, respectively. Moreover, the variation of the area specific power density with lca∈(2 mm, 40 mm) is determined for three representative (rin, tan) combinations. Besides, it is demonstrated that the current output of mtSOFC with proper geometric parameters is comparable to that of planar SOFC.

High performance novel gadolinium doped ceria/yttria stabilized zirconia/nickel layered and hybrid thin film anodes for application in solid oxide fuel cells

Magnetron sputtering under oblique angle deposition was used to produce Ni-containing ultra thin film anodes comprising alternating layers of gadolinium doped ceria (GDC) and yttria stabilized zirconia (YSZ) of either 200 nm or 1000 nm thickness. The evolution of film structure from initial deposition, through calcination and final reduction was examined by XRD, SEM, TEM and TOF-SIMS. After subsequent fuel cell usage, the porous columnar architecture of the two-component layered thin film anodes was maintained and their resistance to delamination from the underlying YSZ electrolyte was superior to that of corresponding single component Ni-YSZ and Ni-GDC thin films. Moreover, the fuel cell performance of the 200 nm layered anodes compared favorably with conventional commercially available thick anodes. The observed dependence of fuel cell performance on individual layer thicknesses prompted study of equivalent but more easily fabricated hybrid anodes consisting of simultaneously deposited Ni-GDC and Ni-YSZ, which procedure resulted in exceptionally intimate mixing and interaction of the components. The hybrids exhibited very unusual and favorable IV characteristics, along with exceptionally high power densities at high currents. Their discovery is the principal contribution of the present work.

Hard anodizing of AA2099-T8 aluminum‑lithium‑copper alloy: Influence of electric cycle, electrolytic bath composition and temperature

AA2099-T8 samples have been hard anodized in a traditional sulphuric bath with the aim of studying the influence of i) electrolyte temperature, ii) Al3+ concentration and iii) different electric cycles in direct current, multi-step direct current and pulsed current (both completely anodic cycles and with cathodic “off” pulses). Anodic oxide thickness, volumetric expansion ratio (Vox/VAl), mean hardness (HV0.05), faradic efficiency and defective state have been analyzed. As temperature decreases, the oxide hardness increases but defectiveness steeply worsens; similarly a middle compromise of Al3+ concentration ensures the best performances. Regimes of high current, from one side, and of low current and current transient, from the other side, strongly affect oxide defective state introducing different types of flaws; an appropriate balance is crucial for a performing non-defected oxide. High current induces the occurrence of parasitic reactions which produce rough and defected Al/ox interface. Low current and current transient induce diffused cracking and detachments of coating fragments which decrease corrosion resistance as shown by potentiodynamic polarization tests. Li-based intermetallics play a crucial role in the last mentioned flaw-creation phenomena since they produce inhomogeneities in electric field distribution and contribute to create unstable oxide structures.

Distribution of Relaxation Times Analysis for Optimization of Anode Thickness in Metal-Supported Microtubular Solid Oxide Fuel Cells

An anode functional layer (AFL) is inserted between anode substrate and electrolyte thin-film to increase the triple phase boundary (TPB) for anode-supported solid oxide fuel cells (SOFCs). On the other hand, better mechanical robustness, redox tolerance, rapid thermal cycling and cost reduction are expected for metal-supported SOFCs. The anode thickness of metal-supported cells (MSCs) is more important than the AFL thickness of anode-supported cells (ASCs), since the metallic substrate does not have TPB. In the present work, the metal-supported microtubular SOFCs with La0.6Sr0.4Co0.2Fe0.8O3(LSCF)-(Ce0.9Gd0.1)O1.95(GDC) cathode, GDC electrolyte, BaCe0.8Y0.2O3- d (BCY) blocking layer and Ni-GDC anode on Ni substrate were investigated. The significant decrease in polarization resistance with increasing the anode thickness from 10 to 16 mm was confirmed by the distribution of relaxation times (DRT) analysis for the metal-supported microtubular SOFCs operated at 550 oC.

A Multi-Scale Modelling Approach and Experimental Calibration Applied to Commercial SOFCs

Introduction SOFC are devices characterised by many parallel phenomena occurring at different time and space scales. Multi-scale models come of aid to the increasing necessity for a correct and detailed representation of the micro-scale level, within a more complex channel or stack model, in order to capture the correct polarisation behaviour of the cells during normal steady state (i.e., design point, off-design), undesirable (i.e., local fuel starvation, coking) and transient (i.e., start-up, shut-down, load following) operation. The present study aims at laying the theoretical basis for a multi-scale modelling approach applicable to state-of-the-art commercial SOFCs. The proposed multi-scale model is built with the main purpose to understand how micro-scale characteristics of the PEN structure and the thermo-chemical and electrochemical phenomena, which occur in the electrode and electrolyte assembly, may affect the overall performance of a complete cell and ultimately of the stack. The final goal is stack performance. Modelling and Experimental Methodology This study presents the integration of two dimensional finite volume models: a 1D micro-scale model and a 1D (or 2D) macro-scale (channel/cell) model. The former simulates the distributed mass and charge transport along the z direction through the thickness of the PEN structure; the mass transport is modelled with a reactive Dusty Gas Model whilst the charge transport with the combination of Ohm’s law and Butler-Volmer equations. The micro-scale model also solves the enthalpy balance through the PEN thickness. The micro structure characteristics of the electrodes and electrolyte structure are determined by means of the percolation theory. The channel model sets the voltage of the equipotential plates and the thermodynamic and chemical inlet conditions of the cell. The macro-scale model simulates the gas diffusion from the electrodes surface to the gas bulk phase in each control volume; moreover, the mass and energy balance are solved. The heat exchange model includes axial and transversal (i.e., contact resistance) conduction, convection (laminar flow) and radiation. The energy balance considers also a heat loss proportional to the outer volume of the reactor. The channel model sets the geometry of the interconnect structure for current collection on each channel. Polarisation experimental data measured on a SOLIDpower S.p.a short-stack test bench are presented, as reported in 1. The short-stack has 6 cells in a co-flow arrangement. The cells are made up of a thin 8 mol% Y2O3 stabilised Zirconia (YSZ) electrolyte (8 ± 2 μm) supported on a conventional porous Ni/YSZ anode electrode (240 ± 20 μm). The cathode electrode (30 ± 2 μm) is constituted by a composite structure of metallic perovskite Sr-doped LaMnO3 (LSM) and oxide-ion conductive electrolyte YSZ. The active area of each cell is 80 cm2, equal to that of the cells employed in the 2.5 kWel micro-CHP units of the manufacturer 2. Results and Discussion The 2D+1D model is first calibrated using the polarisation curve obtained from the short-stack operating with pre-reformed natural gas, as reported in Figure 1. The results show high current density gradients along the channel, primarily due to the fuel flow-field layout and secondly due to the low thermal and composition contribution of the reforming reaction. Moreover, a high importance of thermal losses ( of inlet fuel LHV) is detected. The micro-scale model suggests the limited extent of the electrochemical active thickness on the fuel channel side ( of overall anode thickness), which remains approximately constant throughout the channel length; therefore, the anode structure behaves mainly as structural support as reported in Figure 2. The enthalpy balance within the PEN structure shows negligible temperature gradients (in z direction) along the whole channel length. The optimisation of the stack should therefore focus on the micro-structure characteristics which should change along the channel (xdirection) in relation to the variation of temperature and composition in order to optimise the polarisation behaviour depending on the specific local conditions. A sensitivity analysis on the percolation parameters (thus the TPB length) is presented to support this conclusion. Conclusions Detailed multi-scale models are able to provide a comprehensive description of the phenomena occurring in a complete SOFC system. The model proposed here lays the basis for cell local optimisation and design-led techniques which are required for performance enhancement; the suggested design improvements affect both the micro-scale and the channel-scale levels, respectively in terms of PEN structural and electrochemical parameters and flow-field layout.

Nanosecond Pulsed Plasma Brush for Bacterial Inactivation on Laminate

An array of nonthermal atmospheric-pressure helium plasma jets, in the shape of a brush, was generated in air when a rectangular, 0.1 mm thick anode was powered by 150 ns, 9.5 kV pulses at 2 kHz. With helium as the working gas at 1 slpm, each of the 11 jets of the plasma brush was 1 mm in width, and up to 1 cm long. The jets were spaced 4 mm apart, resulting in a lateral length of 51 mm. The bactericidal effect of the plasma brush was studied against Acinetobacter baumannii and Staphylococcus aureus inoculated on surfaces, including agar and laminate. The impact of humidity in the working gas, substrate type (agar versus laminate), and surface condition (wet versus dry) on the plasma-induced bactericidal effect was evaluated. In a humid discharge, bacterial inactivation was maximized at 0.6 log (75%), whereas adding water to the laminate surface before treatment yielded a 4 log (99.99%) reduction in bacterial viability. In addition, reactive plasma species, including excited O, NO, and OH were evaluated using optical emission spectroscopy for all plasma treatment conditions on laminate.

Comparing the Expected Stack Cost of Next Generation Intermediate Temperature Protonic Ceramic Fuel Cells with Solid Oxide Fuel Cell Technology

Lowering the operating temperature of high-temperature fuel cells has historically been motivated by stack and system cost reduction and durability considerations towards making fuel cells a more attractive distributed generation technology. Protonic ceramic fuel cells (PCFCs) operating beneath 600oC have emerged as a promising technology candidate for developing power generation systems. Recent progress in PCFC development has solved the challenges of poor cathodes and cell fabrication thereby, enabling them to achieve high power density at intermediate temperatures (450-600oC) while demonstrating remarkable fuel flexibility (hydrogen, hydrocarbon gases, alcohols, ammonia) without external fuel processing measures [1]. This ARPA-E funded project focuses on PCFC cells made by solid-state reactive sintering (SSRS) fabrication processes for cells comprised of a thin BaZr0.8Y0.2O3-δ (BZY20) electrolyte screen-printed onto a BZY20/Ni porous anode support, with a triple conducting cathode material based on BaCo0.4Fe0.4Zr0.1Y0.1O3-δ (BCFZY0.1). In this paper, we present an economic manufacturing model that was developed to estimate the overall expected cost of a PCFC stack and compare the results with solid oxide fuel cell (SOFC) technology for hydrogen and methane fuels. The comparative analysis is based on similar cell and stack SOFC manufacturing processes and cost data for small-scale stacks (5-10 kW) at production volumes of about 10,000 units/year. Relying on previous SOFC stack cost manufacturing studies [2, 3] a competitive stack capital cost for PCFCs operating at intermediate temperature is projected. Specifically, operating on methane fuel, the costs of PCFC stacks at 500oC (0.155 W/cm2) and 550oC (0.240 W/cm2) are estimated to be 5-10% lower and ~35% lower, respectively, than SOFC stacks running at 800oC (~0.300 W/cm2). To eliminate any uncertainties using methane fuel gas supply (such as extent of reforming, fuel utilization, steam content, etc.), the PCFC and SOFC stack cost estimates were also benchmarked on 97% hydrogen / 3% water vapor fuel gas where an impressive 29% lower stack cost was estimated for PCFC technology (at 500oC). This potential cost advantage of PCFC vs. SOFC stacks is found despite the 20-50% lower power density of PCFCs and is driven by fewer firing steps and the use of lower lower-grade materials. Improvements to further decrease PCFC stack cost consist of replacing nickel oxide precursor, reducing the anode thickness and merging the two-firing steps into a one-firing step SSRS. Overall, as PCFC power density performance is expected to increase with further development, this work demonstrates that if PCFC technology scale-up to larger platforms is successful, they have excellent potential for filling the technology gap of low-cost, high efficiency distributed generation for small- and intermediate-scale commercial combined heat and power systems.

Distribution of Relaxation Times Analysis for Optimization of Anode Thickness in Metal-Supported Microtubular Solid Oxide Fuel Cells

An anode functional layer (AFL) is inserted between anode substrate and electrolyte thin-film to increase the triple phase boundary (TPB) for anode-supported solid oxide fuel cells (SOFCs). On the other hand, better mechanical robustness, redox tolerance, rapid thermal cycling and cost reduction are expected for metal-supported SOFCs. The anode thickness of metal-supported cells (MSCs) is more important than the AFL thickness of anode-supported cells (ASCs), since the metallic substrate does not have TPB. In the present work, the metal-supported microtubular SOFCs with La0.6Sr0.4Co0.2Fe0.8O3(LSCF)-(Ce0.9Gd0.1)O1.95(GDC) cathode, GDC electrolyte, BaCe0.8Y0.2O3- d (BCY) blocking layer and Ni-GDC anode on Ni substrate were investigated. It was confirmed by the distribution of relaxation times (DRT) analysis that the polarization resistance increased with decreasing the anode thickness from 23 to 10 mm for the metal-supported microtubular SOFCs operated at 550 oC.

Anode Concentration Polarization in Solid Oxide Cells as a Dissipative Process

Part of the voltage of a fuel cell is used up as a loss in irreversible processes that convert potential useful work into heat. This voltage loss is called overpotential or polarization. Voltage loss associated with the transport of gaseous species through porous electrodes is called concentration polarization. This paper describes anode concentration polarization as a dissipative process and determines its spatial dependence through the anode thickness. In concept, using mirco-hydrogen sensors, it should be possible to measure the spatial dependence of anode polarization. Background on the origin of this loss is given using analogies of transport of electrically charged and neutral species.

Binder Free Hierarchical Mesoporous Carbon Foam for High Performance Lithium Ion Battery

A hierarchical mesoporous carbon foam (ECF) with an interconnected micro-/mesoporous architecture was prepared and used as a binder-free, low-cost, high-performance anode for lithium ion batteries. Due to its high specific surface area (980.6 m2/g), high porosity (99.6%), light weight (5 mg/cm3) and narrow pore size distribution (~2 to 5 nm), the ECF anode exhibited a high reversible specific capacity of 455 mAh/g. Experimental results also demonstrated that the anode thickness significantly influence the specific capacity of the battery. Meanwhile, the ECF anode retained a high rate performance and an excellent cycling performance approaching 100% of its initial capacity over 300 cycles at 0.1 A/g. In addition, no binders, carbon additives or current collectors are added to the ECF based cells that will increase the total weight of devices. The high electrochemical performance was mainly attributed to the combined favorable hierarchical structures which can facilitate the Li+ accessibility and also enable the fast diffusion of electron into the electrode during the charge and discharge process. The synthesis process used to make this elastic carbon foam is readily scalable to industrial applications in energy storage devices such as li-ion battery and supercapacitor.

Infiltration of commercially available, anode supported SOFC\u2019s via inkjet printing

Commercially available anode supported solid oxide fuel cells (NiO-8YSZ/8YSZ/LSCF- 20 mm in diameter) were anode infiltrated with gadolinium doped ceria (CGO) using a scalable drop-on-demand inkjet printing process. Cells were infiltrated with two different precursor solutions—water based or propionic acid based. The saturation limit of the 0.5 μm thick anode supports sintered at 1400 °C was found to be approximately 1wt%. No significant enhancement in power output was recorded at practical voltage levels. Microstructural characterisation was carried out after electrochemical performance testing using high resolution scanning electron microscopy. This work demonstrates that despite the feasibility of achieving CGO nanoparticle infiltration into thick, commercial SOFC anodes with a simple, low-cost and industrially scalable procedure other loss mechanisms were dominant. Infiltration of model symmetric anode cells with the propionic acid based ink demonstrated that significant reductions in polarisation resistance were possible.

Modeling the Effect of Carbon to Sulfur Ratio in the Cathode on the Electrochemical Performance of a Li-S Cell

Lithium-Sulfur (Li-S) batteries are one of the most promising energy storage systems beyond Li-ion batteries because of the high specific capacity (1675 mAh/g), low cost, natural abundance and non-toxicity of sulfur [1-3]. Although Li-S batteries have many attractive characteristics, they are facing major problems that are required to be solved to improve the cycle life and capacity retention; the precipitation of the insulating solids on the cathode (S, Li2S), infinite charging due to the polysulfide shuttle mechanism and the instability of the lithium anode [1-3]. Carbon to sulfur ratio in the cathode is one of the most critical design parameters in a Li-S battery [1-3]. Because of the insulating nature of both S and Li2S, Li-S cathodes typically require high C:S ratios [1-3]. As this ratio increases, cathode kinetics are improved due to an enhancement in both electronic conductivity and active surface area. However, techno-economic model predictions in a previous study show that too much increase in the C:S ratio results in a significant decrease at the system-level energy density [1]. Therefore, thoughtful selection of the C:S ratio in the cathode is critical to achieve high-energy density Li-S batteries. In this study, the effect of carbon to sulfur ratio in the cathode on the electrochemical performance of a Li-S cell is modeled. For this purpose, a one-dimensional, concentration-independent electrochemical model for an isothermal, constant-current discharge of a Li-S cell is developed based on a previous model [1, 4]. In the model, the current-voltage relationship is predicted using Butler-Volmer kinetics in the anode, Ohm’s Law in the porous separator and the porous electrode model by Newman and Tobias in the cathode [5]. The effect of C:S ratio in the cathode on the electrochemical performance is investigated at 60% depth of discharge by feeding the model with the experimental cell design parameters from the literature (i.e. carbon to sulfur ratio and electrolyte to sulfur ratio in the cathode, anode, separator and cathode thicknesses and current density in references [2, 3]). Consequently, cell voltage at 60% DOD for different C:S ratios are predicted by the model proposed and compared with the experimental data. Cell voltage at 60% DOD predicted by the model as a function of C:S ratio for two different current densities is shown in Figure 1. It can be seen that the cell voltage increases significantly with increasing C:S ratio, especially up to a C:S ratio of 1. Further increase in the carbon content leads to a less apparent increase in the cell voltage for both current densities. This may suggest that the cell is limited by the kinetics at C:S ratios lower than 1 whereas the improvement on the cathode kinetics is less significant at higher ratios. The model predictions are also validated with the experimental data [2] as shown in the figure. It is clear that the model predictions show close agreement with the experimental data. Figure 1. The effect of C:S ratio in the cathode on the cell voltage at 60% DOD predicted by the model for two different Li-S cell designs [2, 3]. The comparison of the model predictions with the experimental data [2] is also presented.

Prediction of overpotential and effective thickness of Ni/YSZ anode for solid oxide fuel cell by improved species territory adsorption model

Abstract The reliability of analytical model for hydrogen oxidation at Ni/YSZ anode in solid oxide fuel cell named as species territory adsorption model has been improved by introducing referenced thermodynamic and kinetic parameters predicted by density function theory calculations. The model can explicitly predict anode overpotential using unknown values of quantities of state for oxygen migration process in YSZ near a triple phase boundary (TPB), frequency factor for hydrogen oxidation, and effective anode thickness. The former two are determined through careful fitting process between the predicted and experimental results of Ni/YSZ cermet and Ni-patterned anodes. This makes it possible to estimate effective anode thickness, which tends to increase with temperature in six kinds of Ni/YSZ anodes in references. In addition, the comparison between the proposed model and a published numerical simulation indicates that the model can predict more precise dependence of anode overpotential on steam partial pressure than that by Butler-Volmer equation with empirical exchange current density. The introduction of present model into numerical simulation instead of Butler-Volmer equation can give more accurate prediction of anode polarization.

Effect of anode thickness and Cu content on consolidation and performance of planar copper-based anode-supported SOFC

Planar, Cu-containing Gadolinia-doped ceria anode-supported solid oxide fuel cells to be used at intermediate temperature (500–750 °C) were produced in the present work. The Intermediate temperature solid oxide fuel cells were fabricated using Li2O as sintering aid for Gadolinia-doped ceria, varying the anode-to-electrolyte thickness ratio (r) from 2 to 10 and the CuO content in the anode from 45 vol% to 55 vol%. Co-sintering of the thermo-pressed green cells was carried out at 900 °C for 3 h. The electrolyte densification was favoured by increasing the r value, this being accounted for the enhanced compressive stresses induced by the supporting anode on the electrolyte upon sintering. Larger CuO content positively influences the overall cell performance, due to the improved electronic conductivity of the anode. Nevertheless, CuO concentration cannot exceed 50 vol% because of the tensile stresses (and corresponding flaws) generated in the electrolyte for larger amount. IT-SOFC containing 50 vol% CuO was characterized by an Open Circuit Voltage ≈0.82 V and a maximum power density of 200 mW cm−2 at 700 °C.

Preparation of Metallographic Samples with Anodic Layers

Anodization is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, anodic oxide coatings. The thickness of the resulting layer depends on the process parameters (voltage, current, type of electrolyte, concentration and temperature of the electrolyte). In this work, the preparation of zinc metallographic samples with anodic layer is described. Samples prepared by anodic oxidation on the zinc substrate are rather brittle and porous. During the mounting, cutting, grinding and polishing the layer can be deformed which can affect the layer thickness measurements. The problem is to determine the boundary between anodic layer and resin. The cross-sectional micrographs were observed by scanning electron microscopy with the aim to improve anodic layers thickness measurements by means of digital image analysis.

Cross-linked poly(acrylic acid)-carboxymethyl cellulose and styrene-butadiene rubber as an efficient binder system and its physicochemical effects on a high energy density graphite anode for Li-ion batteries

An increase in graphite anode thickness is an effective way to achieve a high-energy density lithium ion battery by designing a compact cell with a high mass loading and density. However, this may cause critical problems in Li+ diffusivity due to drastic increases in length and tortuosity of the ionic migration path. A mixture of cross-linked poly (acrylic acid) (PAA)–carboxymethyl cellulose hydrogels (CMC) was developed using styrene-butadiene rubber (SBR) as an efficient binder system to increase Li+ diffusivity and adhesion strength. Electrolyte permeability and adhesion strength of the electrode were enhanced by 2.5 and 2 times, respectively, compared to a conventional CMC–SBR system, which led to excellent electrochemical properties due to enhanced affinity with electrolytic and interpolymeric properties. Particularly, capacity retention was improved from 81 to 91% at a high 1C rate.