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Full-Text Articles in Engineering
Characteristics Of The Hydrogen Electrode In High Temperature Steam Electrolysis Process, Chao Jin, Chenghao Yang, Fanglin Chen
Characteristics Of The Hydrogen Electrode In High Temperature Steam Electrolysis Process, Chao Jin, Chenghao Yang, Fanglin Chen
Faculty Publications
YSZ-electrolyte supported solid oxide electrolyzer cells (SOECs) using LSM-YSZ oxygen electrode but with three types of hydrogen electrode, Ni–SDC, Ni–YSZ and LSCM–YSZ have been fabricated and characterized under different steam contents in the feeding gas at 850°C. Electrochemical impedance spectra results show that cell resistances increase with the increase in steam concentrations under both open circuit voltage and electrolysis conditions, suggesting that electrolysis reaction becomes more difficult in high steam content. Pt reference electrode was applied to evaluate the contributions of the hydrogen electrode and oxygen electrode in the electrolysis process. Electrochemical impedance spectra and over potential of both electrodes …
Sr2Fe1.5Mo0.5O6 As Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells With La0.8Sr0.2Ga0.87Mg0.13O3 Electrolyte, Guoliang Xiao, Qiang Liu, Fei Zhao, Lei Zhang, Changrong Xia, Fanglin Chen
Sr2Fe1.5Mo0.5O6 As Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells With La0.8Sr0.2Ga0.87Mg0.13O3 Electrolyte, Guoliang Xiao, Qiang Liu, Fei Zhao, Lei Zhang, Changrong Xia, Fanglin Chen
Faculty Publications
The performance of Sr2Fe1.5Mo0.5O6 (SFMO) as a cathode material has been investigated in this study. The oxygen ionic conductivityof SFMO reaches 0.13 S cm-1 at 800°C in air. The chemical diffusion coefficient (Dchem) and surface exchange constant (kex) of SFMO at 750°C are 5.0 x 10-6 cm2 s-1 and 2.8 x 10-5 cm s-1, respectively, suggesting that SFMO may have good electrochemicalactivity for oxygen reduction. SFMO shows a thermal expansion coefficient (TEC) of 14.5 x 10-6 K-1 the …
Single-Particle Model For A Lithium-Ion Cell: Thermal Behavior, Meng Guo, Godfrey Sikha, Ralph E. White
Single-Particle Model For A Lithium-Ion Cell: Thermal Behavior, Meng Guo, Godfrey Sikha, Ralph E. White
Faculty Publications
The single-particle model presented by Santhanagopalan et al. [ J. Power Sources , 156 , 620 (2006)] is extended to include an energy balance. The temperature dependence of the solid phase diffusion coefficient of the lithium in the intercalation particles, the electrochemical reaction rate constants, and the open circuit potentials (OCPs) of the positive and negative electrodes are included in the model. The solution phase polarization is approximated using a nonlinear resistance, which is a function of current and temperature. The model is used to predict the temperature and voltage profiles in a lithium-ion cell during galvanostatic operations. The single-particle …
Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue
Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue
Faculty Publications
Porous electrode is the critical component of solid-oxide fuel cells (SOFCs) and provides a functional material backbone for multi-physicochemical processes. Model based electrode designs could significantly improve SOFC performance. This task is usually performed via parameter studies for simple case and assumed property distributions for graded electrodes. When nonlinearly coupled multiparameters of electrodes are considered, it could be very difficult for the model based parameter study method to effectively and systematically search the design space. In this research, the optimization approach with a genetic algorithm is demonstrated for this purpose. An anode-supported proton conducting SOFC integrated with a fuel supply …
Theoretical Analysis Of Stresses In A Lithium Ion Cell, Sindhuja Renganathan, Godfrey Sikha, Shriram Santhanagopalan, Ralph E. White
Theoretical Analysis Of Stresses In A Lithium Ion Cell, Sindhuja Renganathan, Godfrey Sikha, Shriram Santhanagopalan, Ralph E. White
Faculty Publications
A mathematical model to simulate the generation of mechanical stress during the discharge process in a dual porous insertion electrode cell sandwich comprised of lithium cobalt oxide and carbon is presented. The model attributes stress buildup within intercalation electrodes to two different aspects: changes in the lattice volume due to intercalation and phase transformation during the charge/discharge process. The model is used to predict the influence of cell design parameters such as thickness, porosity, and particle size of the electrodes on the magnitude of stress generation. The model developed in this study can be used to understand the mechanical degradation …
La0.85Sr0.15Mno3− Infiltrated Y0.5Bi1.5O3 Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells, Jiang Zhiyi, Changrong Xia, Fei Zhao, Fanglin Chen
La0.85Sr0.15Mno3− Infiltrated Y0.5Bi1.5O3 Cathodes For Intermediate-Temperature Solid Oxide Fuel Cells, Jiang Zhiyi, Changrong Xia, Fei Zhao, Fanglin Chen
Faculty Publications
Porous yttria-stabilized bismuth oxides (YSB) were investigated as the backbones for (LSM) infiltrated cathodes in intermediate-temperature solid oxide fuel cells. The cathodes were evaluated using anode-supported single cells with scandia-stabilized zirconia as the electrolytes. With humidified as the fuel, the cell showed peak power density of 0.33, 0.52, and at 650, 700, and , respectively. At , the cell polarization resistance was only , of the lowest value previously reported, indicating that YSB is a promising backbone for the LSM infiltrated cathode.
Sulfur Dioxide Crossover During The Production Of Hydrogen And Sulfuric Acid In A Pem Electrolyzer, John A. Staser, John W. Weidner
Sulfur Dioxide Crossover During The Production Of Hydrogen And Sulfuric Acid In A Pem Electrolyzer, John A. Staser, John W. Weidner
Faculty Publications
A proton exchange membrane (PEM) electrolyzer has been investigated as a viable system for the electrolysis step in the thermochemical conversion of sulfur dioxide to sulfuric acid for the large-scale production of hydrogen. Unfortunately, during operation, sulfur dioxide can diffuse from the anode to the cathode. This has several negative effects, including reduction to sulfur that could potentially damage the electrode, consumption of current that would otherwise be used for the production of hydrogen, introduction of oxygen and SO2 to the hydrogen stream, and loss of sulfur to the cycle. However, proper water management can reduce or eliminate the …
Hydrogen Peroxide Formation Rates In A Pemfc Anode And Cathode: Effect Of Humidity And Temperature, Vijay A. Sethuraman, John W. Weidner, Andrew T. Haug, Sathya Motupally, Lesia V. Protsailo
Hydrogen Peroxide Formation Rates In A Pemfc Anode And Cathode: Effect Of Humidity And Temperature, Vijay A. Sethuraman, John W. Weidner, Andrew T. Haug, Sathya Motupally, Lesia V. Protsailo
Faculty Publications
Hydrogen peroxide (H2O2) formation rates in a proton exchange membrane fuel cell (PEMFC) anode and cathode were estimated as a function of humidity and temperature by studying the oxygen reduction reaction (ORR) on a rotating ring disk electrode. Fuel cell conditions were replicated by depositing a film of Pt/Vulcan XC-72 catalyst onto the disk and by varying the temperature, dissolved O2 concentration, and the acidity levels in hydrochloric acid (HClO4). The HClO4 acidity was correlated to ionomer water activity and hence fuel cell humidity. The H2O2 formation rates showed …
Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White
Analytical Expression For The Impedance Response For A Lithium-Ion Cell, Godfrey Sikha, Ralph E. White
Faculty Publications
An analytical expression to predict the impedance response of a dual insertion electrode cell (insertion electrodes separated by an ionically conducting membrane) is presented. The expression accounts for the reaction kinetics and double-layer adsorption processes at the electrode-electrolyte interface, transport of electroactive species in the electrolyte phase, and insertion of species in the solid phase of the insertion electrodes. The accuracy of the analytical expression is validated by comparing the impedance response predicted by the expression to the corresponding numerical solution. The analytical expression is used to predict the impedance response of a lithium-ion cell consisting of a porous LiCoO …
Durability Of Perfluorosulfonic Acid And Hydrocarbon Membranes: Effect Of Humidity And Temperature, Vijay A. Sethuraman, John W. Weidner, Andrew T. Haug, Lesia V. Protsailo
Durability Of Perfluorosulfonic Acid And Hydrocarbon Membranes: Effect Of Humidity And Temperature, Vijay A. Sethuraman, John W. Weidner, Andrew T. Haug, Lesia V. Protsailo
Faculty Publications
The effect of humidity on the chemical stability of two types of membranes [i.e., perfluorosulfonic acid type (PFSA, Nafion 112) and biphenyl sulfone hydrocarbon type, (BPSH-35)] was studied by subjecting the membrane electrode assemblies (MEAs) to open-circuit voltage (OCV) decay and potential cycling tests at elevated temperatures and low inlet-gas relative humidities. The BPSH-35 membranes showed poor chemical stability in ex situ Fenton tests compared to that of Nafion membranes. However, under fuel cell conditions, BPSH-35 MEAs outperformed Nafion 112 MEAs in both the OCV decay and potential cycling tests. For both membranes, (i) at a given temperature, …
Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White
Thermal Model For A Li-Ion Cell, Karthikeyan Kumaresan, Godfrey Sikha, Ralph E. White
Faculty Publications
A thermal model for a lithium-ion cell is presented and used to predict discharge performance at different operating temperatures. The results from the simulations are compared to experimental data obtained from lithium-ion pouch cells. The model includes a set of parameters (and their concentration and temperature dependencies) that has been obtained for a lithium-ion cell composed of a mesocarbon microbead anode, LiCoO2 cathode in 1 M LiPF6 salt, in a mixture of ethylene carbonate, propylene carbonate, ethyl-methyl carbonate, and diethyl carbonate electrolyte. The parameter set was obtained by comparing the model predictions to the experimental discharge profiles obtained …
Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White
Parameter Estimation And Life Modeling Of Lithium-Ion Cells, Shriram Santhanagopalan, Qi Zhang, Karthikeyan Kumaresan, Ralph E. White
Faculty Publications
Lithium-ion pouch cells were cycled at five different temperatures (5, 15, 25, 35, and 45°C ), and rate capability studies were performed after every hundred cycles. The data were used with a simple physics-based model to estimate parameters that capture the capacity fade in the cell, with cycling. The weight of active material within each electrode was estimated as a function of time, using rate capability data at the C/33 rate. The C-rate for these cells is 1.656 A. The capacity fade due to the loss of active material and that due to the loss of cyclable lithium …
Analytical Expression For The Impedance Response Of An Insertion Electrode Cell, Godfrey Sikha, Ralph E. White
Analytical Expression For The Impedance Response Of An Insertion Electrode Cell, Godfrey Sikha, Ralph E. White
Faculty Publications
An analytical expression for the impedance response of an insertion cathode/separator/foil anode cell sandwich is presented. The analytical expression includes the impedance contributions from interfacial kinetics, double-layer adsorption, and solution-phase and solid-phase diffusion processes. The validity of the analytical solution is ascertained by comparison with the numerical solution obtained for a LiCoO2 /polypropylene/lithium metal cell. The flexibility of the analytical solution is utilized to analyze various limiting conditions. An expression to estimate solid-phase diffusion coefficient of insertion species in a porous electrode influenced by the solution-phase diffusion process is also derived
Low-Temperature Synthesis Of A Ptru/Nb0.1ti0.9o2 Electrocatalyst For Methanol Oxidation, Brenda L. García, Roderick Fuentes, John W. Weidner
Low-Temperature Synthesis Of A Ptru/Nb0.1ti0.9o2 Electrocatalyst For Methanol Oxidation, Brenda L. García, Roderick Fuentes, John W. Weidner
Faculty Publications
Niobium was doped into anatase TiO2 support at 10 mol % (Nb0.1Ti0.9O2) using sol-gel chemistry. A PtRu/Nb0.1Ti0.9O2 catalyst was synthesized by LiBH4 reduction in tetrahydrofuran. The methanol electro-oxidation activity of the catalyst shows that this oxide support was electrically conductive. The current (A/gPt) was 6% higher on the PtRu/Nb0.1Ti0.9O2 catalyst compared to a commercial PtRu/C catalyst at 25°C. The electrochemically active surface area of the PtRu/C was 94% higher than PtRu/Nb0.1Ti0.9O2, thus the current per active site was 100% higher on PtRu/Nb0.1Ti0.9O2. A membrane electrode assembly with PtRu/Nb0.1Ti0.9O2 had 46% higher current (A/gPt) than an equivalent E-TEK membrane electrode assembly …
Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov
Novel Pemfc Cathodes Prepared By Pulse Deposition, Subasri M. Ayyadurai, Yoon-Seok Choi, Prabhu Ganesan, Swaminatha P. Kumaraguru, Branko N. Popov
Faculty Publications
A pulse electrodeposition method of preparing thin platinum catalyst layers for polymer electrolyte membrane fuel cell (PEMFC) cathodes has been developed through surface activation of the gas diffusion layer (GDL) by a wetting agent. The performance of the catalyst layer was optimized by wetting agent type, immersion time in the wetting agent, and pulse deposition parameters such as total charge density, peak current density, and duty cycle ratio. The Toff time played a more important role than the Ton time in determining the electrode characteristics such as high concentration of Pt, smaller particle size, and loading. Pt cathodes …
Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov
Development Of Method For Synthesis Of Pt–Co Cathode Catalysts For Pem Fuel Cells, Xuguang Li, Héctor R. Colón-Mercado, Gang Wu, Jong-Won Lee, Branko N. Popov
Faculty Publications
A procedure was developed to synthesize a platinum–cobalt (Pt–Co) alloy electrocatalyst for oxygen reduction using Co/C composite as a support. The Pt–Co/C catalysts were synthesized through: (i) chemical oxidation of carbon black, (ii) Co deposition on the oxidized carbon using a chelation method, (iii) chemical treatment in an acidic medium to remove excess of Co on the carbon surface, (iv) Pt deposition onto the Co/C support, and (v) postheat treatment to form the Pt–Co alloy catalyst. The synthesized Pt–Co/C catalyst showed improved activity and long-term stability in polymer electrolyte membrane …
Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White
Moving Boundary Model For The Discharge Of A Licoo2 Electrode, Qi Zhang, Ralph E. White
Faculty Publications
A moving boundary model in a spherical LiCoO2 particle is presented to account for the diffusion controlled phase transition in LiCoO2 solid particles, and this model is incorporated into a porous electrode model for the LiCoO2 electrode. The simulation results agree well with the experimental data of a LiCoO2 electrode. A study of the flux distribution in the porous electrode shows that the phase transition phenomenon in the LiCoO2particles has a significant effect on the flux distribution by changing the solid phase diffusion resistance in the particles.
Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White
Simulation Of Polarization Curves For Oxygen Reduction Reaction In 0.5 M H2So4 At A Rotating Ring Disk Electrode, Qingbo Dong, Shriram Santhanagopalan, Ralph E. White
Faculty Publications
A cylindrical two-dimensional model based on the Nernst–Planck equations, the Navier–Stokes equation, and the continuity equation is used to simulate the oxygen reduction reaction in 0.5MH2SO4 at a rotating ring disk electrode. Concentration distributions and a potential profile are obtained as a function of the axial and radial distances from the center of the electrode surface. Polarization curves are simulated to interpret experimental results by studying various reaction mechanisms, i.e., the four-electron-transfer reduction of oxygen, the two-electron-transfer reduction of oxygen, a combination of the above two reactions, mechanisms with reduction of peroxide to water, and/or the heterogeneous …
Modeling Volume Changes In Porous Electrodes, Parthasarathy M. Gomadam, John W. Weidner
Modeling Volume Changes In Porous Electrodes, Parthasarathy M. Gomadam, John W. Weidner
Faculty Publications
A three-dimensional mathematical model is presented to describe volume changes in porous electrodes occurring during operation. Material conservation equations are used to derive governing relationships between electrode dimensions and porosity for deposition/precipitation, intercalation, and ionomer-based electrodes. By introducing a parameter, called the swelling coefficient, the relative magnitudes of the change in electrode dimensions and the change in porosity are determined. The swelling coefficient is design-dependent and measured experimentally for a given cell design. The model is general and forms a critical addition required to extend the existing porous electrode models to include volume change effects. For the special case of …
Transient Analysis Of A Porous Electrode, Sheba Devan, Venkat R. Subramanian, Ralph E. White
Transient Analysis Of A Porous Electrode, Sheba Devan, Venkat R. Subramanian, Ralph E. White
Faculty Publications
An analytical expression is presented for the voltage response including the transient voltage for a simple (i.e., no concentration gradients) porous electrode model subject to a sinusoidal input current density. The transient voltage response as a function of the frequency, exchange current density, and double layer capacitance is studied independent of the periodic (steady state) voltage response. The change in the voltage response in the transient region is compared to that of the periodic voltage response with respect to the parameters. The physical properties of the porous electrode can be estimated using the voltage response in the transient …
Cubic Spline Regression For The Open-Circuit Potential Curves Of A Lithium-Ion Battery, Qingzhi Guo, Ralph E. White
Cubic Spline Regression For The Open-Circuit Potential Curves Of A Lithium-Ion Battery, Qingzhi Guo, Ralph E. White
Faculty Publications
A cubic spline regression model was used to fit the experimental open-circuit potential (OCP) curves of two intercalation electrodes of a lithium-ion battery. All the details of an OCP curve were accurately predicted by the resulting model. The number of regression intervals used to fit an OCP curve was determined in a way such that in each regression interval the OCP exhibits a profile predictable by a third-order polynomial. The locations of the data points used to separate regression intervals were optimized. Compared to a polynomial model with the same number of fitting parameters, the cubic spline regression model is …
Effect Of Porosity On The Capacity Fade Of A Lithium-Ion Battery: Theory, Godfrey Sikha, Branko N. Popov, Ralph E. White
Effect Of Porosity On The Capacity Fade Of A Lithium-Ion Battery: Theory, Godfrey Sikha, Branko N. Popov, Ralph E. White
Faculty Publications
A mathematical model is presented to predict the performance of a lithium-ion battery. It includes the changes in the porosity of the material due to the reversible intercalation processes and the irreversible parasitic reaction. The model was also extended to predict the capacity fade in a lithium-ion battery based on the unwanted parasitic reaction that consumes Li+ along with the changes in the porosities of the electrodes with cycling due to the continuous parasitic side reaction. The model can be used to predict the drop in the voltage profile, change in the state of charge, and the effects of …
Analytical Solution For The Impedance Of A Porous Electrode, Sheba Devan, Venkat R. Subramanian, Ralph E. White
Analytical Solution For The Impedance Of A Porous Electrode, Sheba Devan, Venkat R. Subramanian, Ralph E. White
Faculty Publications
A macrohomogeneous model is presented for a porous electrode that includes coupled potential and concentration gradients with linear kinetics. The equations are solved to obtain an analytical expression for the impedance of a porous electrode. Complex plane plots are presented that illustrate two well-defined arcs: a kinetic arc and a diffusion arc with their time constants far apart. The effects of parameters such as exchange current density, porosity, diffusion coefficient, thickness, and interfacial area on the impedance spectra are presented. The usefulness of the analytical solution in investigating the effect of solution phase diffusion is also presented.
Cycle Life Modeling Of Lithium-Ion Batteries, Gang Ning, Branko N. Popov
Cycle Life Modeling Of Lithium-Ion Batteries, Gang Ning, Branko N. Popov
Faculty Publications
A first-principles-based charge-discharge model was developed to simulate the capacity fade of Li-ion batteries. The model is based on the loss of active lithium ions due to solvent reduction reaction and on the rise of the anode film resistance. The effect of parameters such as exchange current density, depth of discharge (DOD), end of charge voltage, film resistance, and the overvoltage of parasitic reaction were studied quantitatively. The model controls the required DOD by controlling the discharge time and estimates the end of discharge voltages as a function of cycle number.
Series Solution To The Transient Convective Diffusion Equation For A Rotating Disk Electrode, Shiriram Santhanagopalan, Ralph E. White
Series Solution To The Transient Convective Diffusion Equation For A Rotating Disk Electrode, Shiriram Santhanagopalan, Ralph E. White
Faculty Publications
A series solution to the transient convective diffusion equation for the rotating disc electrode system is presented and compared to previously reported solutions. The solution presented here is for the entire time domain and agrees well with both the short and long time solutions presented earlier in the literature.
Parameter Estimates For A Pemfc Cathode, Qingzhi Guo, Vijay A. Sethuraman, Ralph E. White
Parameter Estimates For A Pemfc Cathode, Qingzhi Guo, Vijay A. Sethuraman, Ralph E. White
Faculty Publications
Five parameters of a model of a polymer electrolyte membrane fuel cell (PEMFC) cathode (the volume fraction of gas pores in the gas diffusion layer, the volume fraction of gas pores in the catalyst layer, the exchange current density of the oxygen reduction reaction, the effective ionic conductivity of the electrolyte, and the ratio of the effective diffusion coefficient of oxygen in a flooded spherical agglomerate particle to the square of that particle radius) were determined by least-squares fitting of experimental polarization curves. The values of parameters obtained in this work indicate that ionic conduction and gas-phase transport are two …
A Steady-State Impedance Model For A Pemfc Cathode, Qingzhi Guo, Ralph E. White
A Steady-State Impedance Model For A Pemfc Cathode, Qingzhi Guo, Ralph E. White
Faculty Publications
A model for the simulation of the steady-state impedance response of a polymer electrolyte membrane fuel cell (PEMFC) cathode is presented. The catalyst layer of the electrode is assumed to consist of many flooded spherical agglomerate particles surrounded by a small volume fraction of gas pores. Stefan-Maxwell equations are used to describe the multicomponent gas-phase transport occurring in both the gas diffusion layer and the catalyst layer of the electrode. Liquid-phase diffusion of O2 is assumed to take place in the flooded agglomerate particles. Newman’s porous electrode theory is applied to determine over-potential distributions. © 2004 The Electrochemical Society. All …
Analysis Of Molten Carbonate Fuel Cell Performance Using A Three-Phase Homogeneous Model, N. Subramanian, B. S. Haran, P. Ganesan, Ralph E. White, Branko N. Popov
Analysis Of Molten Carbonate Fuel Cell Performance Using A Three-Phase Homogeneous Model, N. Subramanian, B. S. Haran, P. Ganesan, Ralph E. White, Branko N. Popov
Faculty Publications
In this study a three-phase homogeneous model was developed to simulate the performance of the molten carbonate fuel cell (MCFC) cathode. The homogeneous model is based on volume averaging of different variables in the three phases over a small volume element. This approach can be used to model porous electrodes as it represents the real system much better than the conventional agglomerate model. Using the homogeneous model the polarization characteristics of the MCFC cathode was studied under different operating conditions.
Theoretical Analysis For Obtaining Physical Properties Of Composite Electrodes, Parthasarathy M. Gomadam, John W. Weidner, Thomas A. Zawodzinski, Andrew P. Saab
Theoretical Analysis For Obtaining Physical Properties Of Composite Electrodes, Parthasarathy M. Gomadam, John W. Weidner, Thomas A. Zawodzinski, Andrew P. Saab
Faculty Publications
A theoretical analysis is presented that allows in situ measurements of the physical properties of a composite electrode, namely, the electronic conductivity, the ionic conductivity, the exchange-current density, and the double-layer capacitance. Use is made of the current-voltage responses of the composite electrode to dc and ac polarizations under three different experimental configurations. This analysis allows the physical properties to be obtained even when the various resistances in the composite (e.g., ionic, electronic, and charge-transfer) are of comparable values.
A Mathematical Model Of Oxide/Carbon Composite Electrode For Supercapacitors, Hansung Kim, Branko N. Popov
A Mathematical Model Of Oxide/Carbon Composite Electrode For Supercapacitors, Hansung Kim, Branko N. Popov
Faculty Publications
A pseudo two-dimensional model is developed for the general application of supercapacitors consisting of an oxide/carbon composite electrode. The model takes into account the diffusion of protons in the oxide particle by employing the method of superposition. RuO2/carbon system is modeled as a specific example. From the simulation data, it is found that the oxide particle size and proton diffusion coefficient have an enormous effect on the performance at high discharge rate due to the limitation of proton transport into RuO2 particles. With increasing carbon ratio, the porosity of electrode increases, which causes the potential drop in …