High-purity Hydrogen Production Research Articles

Modifying Ionic Membranes with Carbon Dots Enables Direct Production of High-Purity Hydrogen through Water Electrolysis.

Traditional electrolysis of water produces hydrogen with a purity of ∼98%. Using ion transport membranes to prevent the migration of oxygen (O2) from the anode to the cathode, the purity of H2 can be increased to ∼99.8%, but it still cannot fulfill the requirement for use in fuel cells (>99.97%). Here, we report that modifying a commercial ionic membrane (Nafion) with carbon dots (CDs) can further inhibit O2 permeation across the membrane, while effectively improving its ion transportability. The key to achieve these effects is the rational design and proper loading of the CDs, which narrows the pore size of the membrane from ∼4 nm to <2 nm and alters its surface functionality. Using the CDs-modified Nafion membrane in an H-type electrolysis cell, we demonstrate that H2 with a purity of up to 99.98%, which meets the standards of hydrogen fuel cells, can be directly produced without any additional purification process. Our study provides a new route for the low-cost electrolysis of water to produce high-purity hydrogen.

Experimental and thermodynamic study on sorption-enhanced steam reforming of toluene for H2 production using the mixture of Ni/perovskite-CaO

It is known that a considerable amount of tar is usually generated in the biomass gasification process, and catalytic steam reforming is an effective method to remove this by-product. The coupling of in-situ CO2 capture in the process can further shift the forward reforming reaction and produce hydrogen with a high purity. In this work, sorption enhanced steam reforming (SESR) of toluene (as a model compound of biomass tar) was investigated thermodynamically and experimentally using the mechanically mixed Ni/perovskite catalyst and CaO sorbent. It is verified that the appropriate temperature is 650 °C under stoichiometric reaction (S/C = 2), and around 75% average H2 yield with a maximum H2 purity over 95% could be obtained. Moreover, the cyclic SESR-regeneration and characterization including XRD, SEM/EDS, TEM and XPS were carried out, and it shows a stable catalytic performance and compatibility of the Ni/perovskite catalyst in the SESR process for high-purity hydrogen production.

Robust multi-objective optimization of methanol steam reforming for boosting hydrogen production

Methanol steam reforming (MSR) has been considered as a promising method for producing pure hydrogen in recent decades. A comprehensive two-dimensional steady-state mathematical model was developed to analyze the MSR reactor. To improving high purity hydrogen production, a triple-objective optimization of the MSR reactor is performed. Non-dominated Sorting Genetic Algorithm-II (NSGA-II) is employed as a robust optimization approach to maximize the three objectives, termed as, methanol conversion, CO selectivity, and H2 selectivity. The Pareto optimal frontier has also been provided and the ultimate solution of the Pareto front has been found by the three decision-making methods (TOPSIS, LINMAP, and Shannon's Entropy). Among the three distinct decision-making approaches, LINMAP presents better results according to the deviation index parameter. It has been shown that a perfect agreement is available between the plant and simulation data. Operating under the optimum values based on the LINMAP method confirms an almost 47.04% enhancement of H2 mass fraction compared to the conventional industrial MSR reactor. The predicted results advocate that the key superiority of the optimized-industrial reactor is the remarkable higher production rate of hydrogen compared to the conventional MSR reactor which makes optimized-industrial reactor both feasible and beneficial.

Multifunctional Ni-based oxygen carrier for H2 production by sorption enhanced chemical looping reforming of ethanol

The sorption enhanced chemical looping reforming is a prospective technology for high-quality hydrogen production. In this technology, the full benefits of catalysis, oxygen transfer, and CO2 adsorption are achieved by the utilization of oxygen carriers and sorbents. However, most sorbents that are mixed physically into the reforming bed are liable to encountering ash fouling and porosity reduction, preventing CO2 adsorption and sorbent regeneration. In this work, we develop a multifunctional composite oxygen carrier, which combines the NiO/NiAl2O4 catalyst with the CaO sorbent into a one-body composite pellet. Compared with the conventional physically mixed oxygen carrier, the composite oxygen carrier shows uniform element distribution, superior reducibility, and shortened dead time, resulting in enhanced CO2 adsorption capacity, high H2 production efficiency, and excellent ethanol conversion. Furthermore, during 20 cycle tests, the stable CO2 adsorption capacity and H2 concentration of composite oxygen carrier were maintained, while the H2 concentration of mixed oxygen carrier sharply decreased because of deteriorated adsorption performance. The results confirm that the multifunctional composite oxygen carrier is more suitable than the mixed oxygen carrier for CO2 adsorption and high purity hydrogen production. This work opens a new avenue toward the performance improvement of oxygen carriers.

Bio-oil chemical looping reforming coupled with water splitting for hydrogen and syngas coproduction: Effect of supports on the performance of Ni-Fe bimetallic oxygen carriers

In this study, chemical looping reforming coupled with water splitting (CLRWS) process for coproduction of syngas and hydrogen using bio-oil model compound as fuel was investigated. The process simulation results indicated that the mass ratio of fuel to Fe2O3 (F/O) of 0.3 at 900 °C was suitable for syngas and hydrogen coproduction. Under these conditions, the CLRWS experiments were conducted in the fixed bed reactor using Ni-Fe bimetallic oxygen carriers (OCs). The Ni-Fe bimetallic oxygen carrier contained 5 wt% of NiO, 60 wt% of Fe2O3 and 35 wt% of support. Six metal oxides, Al2O3, CeO2, La2O3, MgO, TiO2 and ZrO2, were used as supports, and corresponding OCs were termed as NFA, NFC, NFL, NFM, NFT and NFZ, respectively. The interaction between different components had significant influence on coproduction of syngas and hydrogen. The formation NiAl2O4, FeAl2O4, MgFe2O4, and Fe2TiO5 were unreadily reduced and unfavorable for the high purity hydrogen production in SR. The NFL, NFZ and NFC presented the better performance than the NFA, NFM and NFT. The catalytic reforming reactions were enhanced significantly by introducing NiO and the supports, while the presence of Ni readily produced higher carbon deposition, which could be alleviated by the addition of steam in FR. The hydrogen purity of all OCs increased to more than 95% in the SR with S/C = 1.4. The top two hydrogen purity in SR for NFZ and NFC were 99.73% and 99.66%, the corresponding hydrogen yield were 1.132 Nm3/kg and 1.165 Nm3/kg, respectively. The NFL exhibited excellent catalytic performance and benefited to produce syngas. The NFZ had the highest oxygen transfer capacity and the lowest carbon deposition. The cyclic stability of NFL and NFZ decreased with the increasing of number of cycles. The NFC is a promising OC in the CLRWS process with the presence of steam, maintained high hydrogen purity and good stability performance in the multiple cycle tests.

Modification of NiFe layered double hydroxide by lanthanum doping for boosting water splitting

Electrolysis of water can directly produce hydrogen and oxygen, providing the possibility to expand the production of high purity hydrogen. It consists of two half reactions: anodic oxygen evolution reaction (OER) and cathodic hydrogen evolution reaction (HER). Developing electrocatalysts is an effective way to improve the efficiency of water splitting. Two-dimensional layered double hydroxides (LDHs), as abundant, cheap and bifunctional catalysts, have the similar electrocatalytic performance as precious metals, thereby receiving pretty much attention. Here, a facile flash nano-precipitation (FNP) synthetic strategy is presented to acquire NiFe LDH. Based on it, La-NiFe LDH is obtained by adding rare earth element lanthanum (La) with different contents using mechanical method. Owing to the synergistic effect between La and laminate metal, La-NiFe LDH shows an excellent water splitting performance, where the overpotential of OER activity is 340 mV and HER performance is 57 mV at the current density of 10 mA∙cm−2. Combined with characterization, performance and theoretical calculation, it is confirmed that the electronic structure of LDH laminates can be adjusted by La doping, reducing the Gibbs free energy in the reaction accordingly, which is beneficial to the water splitting reaction. In general, an easy-to-implement and rapid preparation method provides a convenient and green way to obtain water splitting catalyst with enhanced performance.

A techno-economic analysis of solar catalytic chemical looping biomass refinery for sustainable production of high purity hydrogen

Compared to traditional biomass and coal-fired power plants, a process that includes integrated pyrolysis and subsequent gasification is a promising technology to deliver a larger electrical output through the production of high-purity hydrogen with a low carbon footprint. Chemical looping can further enhance the biomass contribution to the global renewable energy demand while fulfilling the stringent CO2 emission cuts needed in the energy sector. This study aims at investigating the feasibility of developing a solar catalytic chemical looping biomass refinery (SCCLBR) power plant for sustainable production of energy using a comprehensive plant modeling and techno-economic assessment. The plant is composed of 7 sequential units: i) biomass preparation (drying, transferring, and grinding), ii) reacting unit (SCCLBR), iii) water gas shift unit and heat recovery, iv) CO2 and H2S separation (Rectisol Process), v) sulfur removal (Claus Process), vi) air separation and vii) catalyst regeneration. The simulation was performed for 1–6 tonne/hour of biomass as input. The effect of key variables (feedstock load, water injection, and temperature) on the economic performance of the plant were analyzed. The simulated results of the chemical looping reactor were validated against the experimental results, while the results of Rectisol and air separation units were validated against the thermodynamic simulation. The results demonstrated that the CCLBR (without solar integration) and integrated SCCLBR can reach the efficiency of 34% and 41% respectively, yet the results have not been optimized. The sensitivity analysis indicated that water injection rate is the most influential parameter, which can even suppress the impact of biomass loading rate. A separate thermodynamic simulation was also performed to investigate the reaction equilibrium of oxygen carrier regeneration (Ca2Fe2O5) using CO2. The results demonstrated that a temperature above 730 °C is required to avoid carbonation (Fe2O3 and CaCO3 production). The maximum greenhouse gas emission in SCCLBR is 10.70, which is significantly lower than traditional coal-to-hydrogen and biomass-to-hydrogen power plants. It has also been found that across varying feedstock input rates, greenhouse gas emissions average 12.8% lower when solar PV supplements refinery power needs; optimization of the steam/biomass ratio may reduce emissions even further.

Promoting Bifunctional Water Splitting by Modification of the Electronic Structure at the Interface of NiFe Layered Double Hydroxide and Ag.

Electrochemical water splitting is a promising method for the renewable production of high-purity hydrogen via the hydrogen evolution reaction (HER). Ni-Fe layered double hydroxides (Ni-Fe LDHs) are highly efficient materials for mediating the oxygen evolution reaction (OER), a half-reaction for water splitting at the anode, but LDHs typically display poor HER performance. Here, we report the preparation of self-organized Ag@NiFe layered double hydroxide core-shell electrodes on Ni foam (Ag@NiFe/NF) prepared by galvanic etching for mediating both the HER and OER (bifunctional water-splitting electrocatalysis). This synthetic strategy allowed for the preparation of organized hierarchical architectures which displayed improved the electrochemical performance by tuning the electronic structure of the catalyst and increasing the surface area utilization. X-ray photoelectron spectroscopy (XPS) and theoretical calculations revealed that electron transfer from the Ni-Fe LDH to Ag influenced the adsorption of the reaction intermediates leading to enhanced catalytic activity. The Ag@NiFe/NF electrode displayed overpotentials as low as 180 and 80 mV for oxygen and hydrogen evolution, respectively, at a current density of 10 mA cm-2, and improvements in the specific activity by ∼5× and ∼1.5× for the oxygen and hydrogen evolution reaction, respectively, compared to benchmark NiFe hydroxide materials. Additionally, an integrated water-splitting electrolyzer electrode can be driven by an AA battery.

Graphene oxide supported transition metal mixed oxide nanourchins onto bimetallic phosphide coatings as high performance hydrogen evolution electrodes in alkaline media

Recently, electrocatalyst with high reactivity and stability towards hydrogen evolution reactions are necessary for large scale high purity hydrogen production to resist upcoming energy crisis. The transition metal mixed oxide based HER electrocatalyst are promising candidates for hydrogen generation in renewable energy field due to their low-cost nature, ease of commercialization and green nature. Herein, graphene oxide supported MnO2-TiO2 nanourchins synthesized by thermal decomposition technique was incorporated to bimetallic phosphide ENCP coatings by electroless plating technique. During alkaline hydrogen evolution, the incorporation of composite onto bimetallic phosphide causes a drastic decreases in overpotential value to 190 mV dec−1 and respective Tafel slope value to 45 mV dec−1. The studies reveals that the modified electrode follows Volmer–Heyrovsky mechanism. The lower Rct of 140.8 Ω and a high Cdl value obtained from Nyquist plot of modified electrodes ensures the fastest electron transfer kinetics and confirms its more facile electrocatalytic nature towards hydrogen evolution. Also, a high value for exchange current density of modified electrode authenticate its superior HER performance. The modified electrodes was durable, long term stable, economically viable and performance was consistent over a wide span of time during alkaline hydrogen evolution reaction. The enhanced performance of modified electrode can be ascribed to the intermetallic synergetic effect arises within ENCP matrix and MnO2-TiO2 nanourchins. These conclusions lead to innovative insights on future perspective for the development and tuning of novel electrocatalysts with enhanced electrochemical performance for hydrogen evolution reaction.

Porous Fe-Co-P nanowire arrays through alkaline etching as self-supported electrodes for efficient hydrogen production

In the present work, an efficient four-step strategy to fabricate the Fe-Co-P porous nanowire arrays in situ grown on a self-supported carbon cloth (denoted as Fe-Co-P/CC) for developing excellent HER activity is reported. The four steps include the preparation of the CoFeZn-precursor by a hydrothermal reaction, the formation of pore-forming agent (ZnO) after annealing treatment, the alkaline etching of ZnO, and phosphorization. Particularly, the alkaline-etched porous Fe-Co-P nanowire-arrays contribute to enhancing the catalytic activity by the exposure of more electrochemical active sites. The as-prepared Fe-Co-P/CC which was prepared by the rational Co-Fe molar ratio, as a binder-free electrocatalyst, shows a high-performance HER with a small overpotential of 121 mV in 1 M KOH and 124 mV in 0.5 M H2SO4 at a current density of 10 mA·cm−2, as well as a good Tafel slope value of 118 mV/dec and 85 mV/dec in alkaline and acid media, respectively, owing to the well-optimized pore-structures and active sites. Additionally, the catalyst almost maintains its electrochemical activity for about 24 and 16 h under alkaline and acidic conditions, respectively. This work provides a new idea for the synthesis of high-efficiency, binder-free electrodes for high-purity hydrogen production.

High-purity hydrogen production by sorption-enhanced steam reforming of iso-octane over a Pd-promoted Ni-Ca-Al-O bi-functional catalyst

Liquid hydrocarbon fuels produced from fossil resources are potential portable hydrogen carriers given their sufficient supply and extensively available infrastructures. However, effective approaches to hydrogen production from liquid hydrocarbons fuels are still insufficient, especially in the context of carbon emission control. Here, we report that high-purity hydrogen is produced with minimized CO2 emissions via the sorption enhanced steam reforming of iso-octane (SESRI), a model compound of gasoline. With a Pd-promoted Ni-CaO-Ca12Al14O33 bi-functional catalyst, 98.0% purity of hydrogen with 90% hydrogen yield was obtained for 10 consecutive SESRI-decarbonation cycles. XRD, SEM, and TEM techniques revealed that structural and morphological properties of the bi-functional catalyst were preserved after 10 cycles. Raman spectroscopy, CO2-TPO and TGA further demonstrated that coke formation was substantially suppressed in the presence of Pd, which played a key role in maintaining stable SESRI performance in terms of hydrogen production. Our results provide a feasible alternative for production of high-purity hydrogen from liquid fossil fuels, thereby being prospective in meeting the demand of portable hydrogen on short to medium term basis.

Hydrogen energy: development prospects and materials

The review addresses the prospects of global hydrogen energy development. Particular attention is given to the design of materials for sustainable hydrogen energy applications, including hydrogen production, purification, storage, and conversion to energy. The review highlights the key role of oxide-supported metal or alloy nanoparticles as catalysts in the hydrogen production via the conversion of natural gas or alcohols. An alternative approach is the pyrolysis of hydrocarbons giving hydrogen and carbon. The direct production of high-purity hydrogen can be performed using electrolysis or membrane catalysis. Apart from conventional hydrogen storage methods such as the compression and liquefaction, the hydrogen alloy absorption and chemical conversion to liquid carriers (ammonia and toluene cycles) are considered. Fuel cells, containing catalysts and proton-conducting membranes as the key components, are used for hydrogen energy generation. Binary platinum alloys or core – shell structures supported on carbon or oxides can be employed to facilitate the oxygen electroreduction and CO electrooxidation in low-temperature fuel cells. High conductivity and selectivity are provided by perfluorinated sulfonic acid membranes. The high cost of the latter materials dictates the development of alternative membrane materials. A crucial issue in high-temperature fuel cells is the necessity of reducing the operating temperature and ohmic losses. This problem can be solved by designing thin-film materials and replacing oxygen-conducting ceramic membranes by proton-conducting membranes.The bibliography includes 290 references.

High-purity hydrogen production via a water-gas-shift reaction in a palladium-copper catalytic membrane reactor integrated with pressure swing adsorption

A Pd-Cu catalytic membrane reactor (CMR) integrated with pressure swing adsorption (PSA) was developed to produce fuel cell grade hydrogen from syngas. The enhanced water-gas-shift reaction in the Pd-Cu CMR packed with a high-temperature shift catalyst was experimentally conducted by using a carbon monoxide (CO)/hydrogen (H2)/carbon dioxide (CO2) mixture (65:30:5 vol%) at 360–380 °C, 6–10 bar, and a steam/carbon (s/c) ratio of 1–5. Since H2 was used as the sweeping gas, pure H2 could be directly obtained from the permeate side. The temperature inside the packed catalysts was well distributed in the developed CMR module without any specific hotspots during the reaction and separation. The CO conversion in the CMR increased from 85.4% to 94.8% with the recovery of 53.4% to 56.1% when the s/c ratio increased from 1 to 5. The conversion rate was enhanced by 10.0–16.7% compared with the fixed catalytic bed reactor. When four-bed PSA using activated carbon and zeolite was integrated to recover more H2 from the retentate flow, the recovery of H2 was additionally improved by 31.2–35.7%. The integrated Pd-Cu CMR with four-bed PSA could produce H2 of over 99.9991% with a recovery of 91.37% and 8.67 ppm CO. For H2 produced with less than 0.2 ppm CO, the recovery was reduced to 85.99% with 0.15 ppm CO. The feasibility of CMR with PSA to enhance CO conversion and H2 recovery is suggested for the production of fuel cell grade H2 for a proton-exchange membrane fuel cell (ISO 14687).

Interface engineered NiFe2O4−x/NiMoO4 nanowire arrays for electrochemical oxygen evolution

Designing highly active and stable electrocatalysts for oxygen evolution reaction (OER) is the key to success in sustainable water splitting reaction, a sustainable route towards high purity hydrogen production. Interface engineering is one of the most effective strategies for modulating the local electronic structure of active sites to enhance catalytic activity. Herein, NiFe2O4−x nanoparticles were integrated to NiMoO4 nanowires (NiFe2O4−x/NMO) grown on nickel foam to construct an extended interface with strong electronic interactions. The NiFe2O4−x/NMO demonstrates high OER activities as manifested by a low overpotential of 326 mV at a high current density of 600 mA cm−2 and good long-term stability. The intimate interface between NiFe2O4−x and NiMoO4 is responsible for the Fe-facilitated phase transition to active γ-NiOOH phase as revealed by in situ Raman spectroelectrochemical studies. This study outlines how the interface design of integrated nanostructures can optimize the formation of active phase for enhanced catalytic activity.

High purity hydrogen production by plasma membrane reactor

High purity hydrogen production by plasma membrane reactor

Assessment of the Effects of Temperature and Pressure on the Efficiency of High-Purity Hydrogen Production from Hydrocarbon Feedstocks in Membrane-Catalytic Devices

The effects of temperature and pressure on both sides of the membrane on the efficiency of hydrogen production are estimated by mathematical modeling using as examples two types of membrane-catalytic devices for high-purity hydrogen production from hydrocarbon feedstocks with different methods of removing the hydrogen product. Graphs of the results are convenient for prompt selection of the optimal operating temperatures and pressures for producing high-purity hydrogen with a high volumetric yield.

Analysis of Parameters for Producing High-Purity Hydrogen from Natural Gas in a Tubular Type Membrane-Catalytic Module

Mathematical modeling is used to analyze results of laboratory studies of a tubular type membranecatalytic module for high-purity hydrogen production from natural gas. It is shown that the mathematical model can almost exactly describe the experimental data.

Electronic modulation and proton transfer by iron and borate co-doping for synergistically triggering the oxygen evolution reaction on a hollow NiO bipyramidal prism.

Designing an Earth-abundant and inexpensive electrocatalyst to drive the oxygen evolution reaction (OER) for high-purity hydrogen production is of great importance. Herein, the cation (iron) and anion (borate) co-doping strategy was proposed to effectively trigger the OER performance on a low-cost NiO material. The optimal hollow Fe/Bi-NiO bipyramidal prism shows superior OER performance, and displays a low overpotential (261 mV) at 10 mA cm-2, accompanied by a low Tafel slope (46 mV dec-1), excellent intrinsic activity and robust stability. The overall alkaline water splitting using Fe/Bi-NiO/NF as an anode affords low cell voltages of 1.50 and 1.63 V at 10 and 100 mA cm-2, and operates steadily at a high current density of 100 mA cm-2 for 55 h without decay. The excellent electrocatalytic activity could be ascribed to the hollow structure to shorten the mass transfer pathway, the electronic modulation by Fe doping, the increased accessible electroactive sites created by oxygen vacancies through borate doping, and the formation of BO33--OH- to accelerate the deprotonation of OHads.

High-purity hydrogen production by sorption-enhanced methanol steam reforming over a combination of Cu–Zn–CeO2–ZrO2/MCM-41 catalyst and (Li–Na–K) NO3·MgO adsorbent

In this study, sorption-enhanced methanol steam reforming (SEMSR) was applied to generate high-purity hydrogen. The mesoporous MCM-41 as support and CuO, ZnO, CeO2, ZrO2 as active agents and promoters were employed for the catalyst preparation. In addition, (Li–Na–K) NO3·MgO as a CO2 adsorbent was prepared by the wet mixing method. The fresh and used catalysts were characterized by XRD, BET, FTIR, FESEM, TEM, H2-TPR and TGA analyses. Also, the CO2 sorbent was studied by XRD, BET, FESEM, TEM and TGA analyses before and after the reaction. The SEMSR performances of the synthesized catalyst and adsorbent were evaluated experimentally in a fixed-bed reactor. The effect of various conditions such as temperature, WHSV, feed molar ratio and sorbent/catalyst ratio were investigated. The best results were obtained at 300 °C, a feed molar ratio (water/methanol) of 2:1, a WHSV of 1.62 h−1, and the sorbent/catalyst ratio of 8:1, which produced 99.8% hydrogen, 25% more than the hydrogen production during conventional methanol steam reforming. Moreover, the cyclic stability of the catalyst and the sorbent was studied for 10 cycles.

Feasibility Studies of Pulsed Oxidation Mitigation of CO Poisoning in Polymer Electrolyte Fuel Cells

Operation of low temperature polymer electrolyte fuel cells (PEFCs) require up to 99.97% purity hydrogen with CO concentrations mandated to be below 0.2 ppmv by ISO 14687-2 standards [1]. The production and application of such high purity hydrogen increases the fuel price and overall cost of fuel cell operation due to the requirement of additional pre-purification measures. Indian Oil Corporation is the largest producer of reformate hydrogen with up to 99.9% purity in India. It contains traces of methane, carbon monoxide and carbon dioxide as some of the major impurities. This low-cost hydrogen could conceivably be used in PEFCs subject to operando mitigation of CO poisoning with the aid of techniques such as pulsed oxidation [2] and air-bleeding [3] to deliver satisfactory performance [4]. However, the long term impacts of these techniques and their feasibility in terms of overall efficiency and cost must be carefully assessed.In this work, we present a detailed investigation of the pulsed oxidation technique to mitigate the effect of CO poisoning in long term PEFC operation. A single cell PEFC with an active area of 25 cm2 and Pt-Ru as the anode electrocatalyst is subjected to 80 ppm CO fuel at a nominal operating current density. Pulsed oxidation operation for 4000 cycles showed a consistent performance recovery up to 90% compared with pure hydrogen potentials. Performance governing parameters such as average potential, peak potential and droptime are presented to show changes in cell performance and pulsed oxidation efficiency. A one-dimensional transient model is developed to detect variations in cell potential and surface coverages of species during poisoning and its pulsing process. The model results show up to 26 % increase in the overall efficiency of the cell with and without the application of pulsing process as a function of bleed rates (anode flow). The technical and economic feasibility of operating a PEFC with impure hydrogen with pulsing is demonstrated.Acknowledgement: This work was supported by Indian Oil Corporation (R&D) and Simon Fraser University under the SFU-IOCL joint PhD program in clean energy.[1] B. Shabani, M. Hafttananian, S. Khamani, A. Ramiar, A.A. Ranjbar, J. Power Sources. 427 (2019) 21–48.[2] P. J. Sarma, C. L. Gardner, S. Chugh, A. Sharma, E. Kjeang, J. Power Sources (2020)[3] L-Yu Sung, B-Joe Hwang, K-Lin Hsueh, W-Nien Su, C-Chung Yang, J. Power Sources 242 (2013) 264-272[4] C.L. Gardner, D. Mehta, S. Chugh, E. Kjeang, J. Electrochem. Soc. 166 (2019) F3123–F3135 Figure 1