The materialistic viability of proton exchange membrane fuel cells predominantly depends on the membrane properties. Thus, in this paper, an emphasis was made on the preparation of cross‐linked ...composite electrolyte membranes. Primarily, a terpolymer was synthesized by employing monomers of phenolphthalein, 4,4′‐diflorobenzophenone, and sodium 5,5′‐carbonyl bis(2‐fluorobenzene‐sulfonate). To enhance the mechanical characteristics of the terpolymer, it was cross‐linked with bisphenol‐A diglycidyl ether. Furthermore, to boost the performance of the fuel cell of the cross‐linked terpolymer electrolyte, two different sulfonated single‐walled carbon nanotubes were incorporated into cross‐linked terpolymer matrix and the resulting developed electrolytes, respectively, denoted as Bu‐singe‐walled carbon nanotubes (SWCNTs) and Su‐SWCNTs membranes. The physico‐chemical characteristics of the successive electrolytes were tested using discrete techniques. Across the series of membranes, the proton conductivity of the 12 mass% of Bu‐SWCNTs and Su‐SWCNTs varied cross‐linked composite membrane was found to be 0.131 and 0.126 S cm−1 at 80 °C with a relative humidity of 100%. Similarly, the performance of the fuel cell examination ascertained the highest power density of 0.43 and 0.39 W cm−2 for the same membranes. These results are superior to the commercially available Nafion® 117 membrane. Thereby, the above‐mentioned cross‐linked composite membranes might be utilized as constructive applicants for the fuel cell.
Sulfonated SWCNTs and physical appearance of membranes after durability study.
Driving style has a significant effect on the operating economy of fuel cell buses (FCBs). To reduce hydrogen consumption and prolong the fuel cell life of FCBs, this paper proposes an online ...adaptive equivalent consumption minimum strategy (A-ECMS) based on driving style recognition. Firstly, driving data from various drivers is collected, and a standard driving cycle is created. Neural networks are then used to identify driving conditions, and three fuzzy logic recognizers are developed to identify driving styles for different driving conditions. The driving style factor is associated with the equivalent factor using an optimization algorithm that incorporates hydrogen consumption cost and fuel cell degradation cost into the objective function. Simulation results demonstrate that the proposed A-ECMS can reduce equivalent hydrogen consumption, prolong fuel cell life, and result in a 6.2% reduction in total operating cost compared to the traditional method.
This study develops a three-dimensional numerical model of a proton exchange membrane (PEM) fuel cell (PEMFC) to investigate the mass transport characteristics and performance of PEMFC with novel ...two-block structures in the cathode channel. The results reveal that the novel two-block structures improve the efficiency of mass transport and the performance of PEMFC. Effects of the arrangement of two-block structures and the operating conditions on the PEMFC performance are investigated. It is found that the block position closer to the outlet of the channel has greater improvement of the PEMFC performance. The PEMFC performance increases firstly with the block structure number and then decreases, and the best number of block structures is 6 for the present study. The block channel has more evident effect when the PEMFC operated under high current density and small stoichiometric ratio, and the block channel is effective in a wide relative humidity (RH) range.
Display omitted
•Effect of two-block channel on fuel cell mass transport and performance are studied.•Two-block channel increases cell performance with small pressure drop increment.•Fuel cell performance increases firstly with the block number and then decreases.•The optimal number of two-block structure is 6 for the best cell performance.•Applicability of two-block channel under different operating conditions are probed.
The ability of some bacteria to perform Extracellular Electron Transfer (EET) has been explored in bioelectrochemical systems (BES) to obtain energy or chemicals from pure substances or residual ...substrates. Here, a new pyoverdine-producing Pseudomonas aeruginosa strain was isolated from an MFC biofilm oxidizing glycerol, a by-product of biodiesel production. Strain EL14 was investigated to assess its electrogenic ability and products. In an open circuit system (fermentation system), EL14 was able to consume glycerol and produce 1,3-propanediol, an unusual product from glycerol oxidation in P. aeruginosa. The microbial fuel cell (MFC) EL14 reached a current density of 82.4 mA msup.−2 during the first feeding cycle, then dropped sharply as the biofilm fell off. Cyclic voltammetry suggests that electron transfer to the anode occurs indirectly, i.e., through a redox substance, with redox peak at 0.22 V (vs Ag/AgCl), and directly probably by membrane redox proteins, with redox peak at 0.05 V (vs Ag/AgCl). EL14 produced added-value bioproducts, acetic and butyric acids, as well as 1,3 propanediol, in both fermentative and anodic conditions. However, the yield of 1,3-PDO from glycerol was enhanced from 0.57 to 0.89 (mol of 1,3-PDO molsup.−1 of glycerol) under MFC conditions compared to fermentation. This result was unexpected, since successful 1,3-PDO production is not usually associated with P. aeruginosa glycerol metabolism. By comparing EL14 genomic sequences related to the 1,3-PDO biosynthesis with P. aeruginosa reference strains, we observed that strain EL14 has three copies of the dhaT gene (1,3-propanediol dehydrogenase a different arrangement compared to other Pseudomonas isolates). Thus, this work functionally characterizes a bacterium never before associated with 1,3-PDO biosynthesis, indicating its potential for converting a by-product of the biodiesel industry into an emerging chemical product.
The aim of this work is the development of a structured catalyst for the dry reforming of biogas to be used as a pre–reformer in the indirect internal reforming configuration (IIR) of solid oxide ...fuel cells (SOFCs). The structured catalyst is based on NiCrAl foams coated with ruthenium (nominal loading 3.0 wt%) supported on a CaZrsub.0.85Smsub.0.15Osub.3−δ (CZS) perovskite oxide. The powder is produced by solution combustion synthesis and deposited on metallic foams by the wash–coating method. Catalytic tests for the dry reforming of methane (DRM) reaction are carried out at 850 °C, 700 °C and 550 °C for an overall 50 h with CHsub.4/COsub.2 = 1 and p = 1.3 bar at different gas hourly space velocities (GHSVs). The final goal is a proof–of–concept: a laboratory validation of an IIR–SOFC fed by biogas. The carbon amount on spent structured catalysts is evaluated by thermogravimetric analysis and microstructural/compositional investigation.
During the shutdown process of the fuel cell system for vehicles, the air entering the anode chamber can form the hydrogen/air interface, accelerating the carbon corrosion of the catalytic layer. ...According to optimized control strategies, the carbon corrosion of fuel cells can be reduced. Nowadays, the main control strategies include gas purging and the consumption of residual oxygen in the stack by the auxiliary load. However, the oxygen in the fuel cell stack cannot be fully consumed or can cause the single-cell voltage to rise to 0.8 V with an inappropriate discharge current drop rate and auxiliary load resistance value, thus affecting the protective effect of the shutdown strategy. In this work, a shutdown strategy of the fuel cell system is studied. After the experiment, the optimized value of the discharge current drop rate and the auxiliary load resistance were obtained. With the resistance value of 50 Ω and the current drop rate of 7 A/s, the shutdown time of the fuel cell system is 13.5 s and the time of single-cell voltage above 0.82 V in the fuel cell stack is 0.1 s. Thus, the optimized shutdown strategy can reduce the shutdown time.
A reasonably designed energy management strategy (EMS) can guarantee the safe and stable operation of fuel cell hybrid electric vehicle (FCHEV). To optimize the energy conversion efficiency of FCHEV, ...this research proposes a three-level efficiency optimized EMS based on the dual reward functions Q-learning algorithm. Focused on the system overall efficiency, a hardware-in-the-loop experimental platform was built first to compare the effectiveness between the proposed EMS and other existed methods. The results shown that compared with other state-of-art methods, the proposed strategy can effectively improve the energy efficiency of the system, and can slow down the aging of the fuel cell by reducing its operating stress. To further verify the effectiveness of the proposed strategy, varying driving loads profile were tested based on a 1.2-kW hybrid electric vehicle developed in the laboratory. The FCHEV real-time experiment results indicated that the proposed EMS can achieve the average load power matching error of 0.19 W and can optimize the system average overall system efficiency to 52%. The proposed method can help to contribute to the massive commercialization and implementation of the FCHEV.
Fuel starvation is a major cause of anode corrosion in low temperature polymer electrolyte fuel cells. The fuel cell start-up is a critical step, as hydrogen may not yet be evenly distributed in the ...active area, leading to local starvation. The present work investigates the hydrogen distribution and risk for starvation during start-up and after nitrogen purge by extending an existing computational fluid dynamic model to capture transient behavior. The results of the numerical model are compared with detailed experimental analysis on a 25 cm2 triple serpentine flow field with good agreement in all aspects and a required time step size of 1 s. This is two to three orders of magnitude larger than the time steps used by other works, resulting in reasonably quick calculation times (e.g., 3 min calculation time for 1 s of experimental testing time using a 2 million element mesh).
•Advanced Dynamic MPC (AMPC) is designed using a novel multi-objective cost function.•Thermal models of energy systems are employed in AMPC’s decisions.•A Fuzzy Cognitive Map is designed to tune the ...dynamic cost function weights online.•Multi-objective optimization is done to improve the overall performance of FCHEV.•Efficacy of AMPC-based energy management system for FCHEV is verified using ADVISOR.
In this paper, an Advanced Dynamic Model Predictive Control (AMPC) based on a Nonlinear Model Predictive Control (NMPC) framework with a multi-objective cost function driven by dynamic weights is proposed to improve the energy performance of fuel cell hybrid electric vehicles whilst prolonging their component lifetime. By the use of dynamic weights, the cost function is effectively formulated as the combination of fuel consumption, rate of change of fuel cell power, battery power, the fuel cell efficiency, state of charge of the battery, and their temperatures. In order to enhance the adaptability of the AMPC, a Fuzzy Cognitive Map (FCM) is then newly designed to regulate online the dynamic weights to adjust the importance of each cost component according to the conditions prevailing during driving. A comparative study between the proposed AMPC, a constant weight based NMPC and a conventional NMPC having cost function with fewer objectives has been carried out by means of simulation using a FCHEV model from the simulation tool ADVISOR to illustrate the efficacy of the proposed AMPC.
Surface engineering has achieved great success in enhancing the electrochemical activity of Cosub.3Osub.4. However, the previously reported methods always involve high-temperature calcination ...processes which are prone to induce agglomeration of the nanostructure, leading to the attenuation of performance. In this work, Cosub.3Osub.4 nanowires were successfully modified by a low-temperature NHsub.3/Ar plasma treatment, which simultaneously generated a porous structure and efficient nitrogen doping with no agglomeration. The modified N-CoOx electrode exhibited remarkable performance due to the synergistic effect of the porous structure and nitrogen doping, which provided additional active sites for faradic transitions and improved charge transfer characteristics. The electrode achieved excellent supercapacitive performance with a maximum specific capacitance of 2862 mF/cmsup.2 and superior cycling retention. Furthermore, the assembled asymmetric supercapacitor (N-CoOx//AC) device exhibited an extended potential window of 1.5 V, a maximum specific energy of 80.5 Wh/kg, and a maximum specific power of 25.4 kW/kg with 91% capacity retention after 5000 charge-discharge cycles. Moreover, boosted hydrogen evolution reaction performance was also confirmed by the low overpotential (126 mV) and long-term stability. This work enlightens prospective research on the plasma-enhanced surface engineering strategies.
PDF
