Abstract-Power management strategy is as significant as component sizing in achieving optimal fuel economy of a fuel cell hybrid vehicle (FCHV). We have formulated a combined power management/design optimization problem for the performance optimization of FCHVs. This includes subsystem-scaling models to predict the characteristics of components of different sizes. In addition, we designed a parameterizable and near-optimal controller for power management optimization. This controller, which is inspired by our Stochastic Dynamic Programming results, can be included as design variables in system optimization problems. Simulation results demonstrate that combined optimization can efficiently provide excellent fuel economy. IntroductionPower management strategy and component sizing affect vehicle performance and fuel economy considerably in hybrid vehicles because of the multiple power sources and differences in their characteristics.Furthermore, these two important factors are coupled-different design of component sizing should come with different design of power management strategy. Therefore, to achieve maximum fuel economy for hybrid vehicles, optimal power management and component sizing should be determined as a combined package. Our research has formulated and solved a combined power management/design (i.e., control/plant) optimization problem of a fuel cell hybrid vehicle (FCHV).Development of the power management strategy is one of the important tasks in developing hybrid vehicles and relatively many literatures can be found. to determine an optimal power distribution for a fuel cell/supercapacitor hybrid vehicle. The concept of equivalent factors in hybrid electric vehicles has been described by Sciarretta et al. [3]. In the same research, they also compared their power management result to deterministic dynamic programming result, which can lead to a global optimality. Another reference was published from Argonne National Laboratory [10], with an approach similar to [9]. In addition to component sizing optimization, Markel et al. [11] summarized design issues such as cost and volume in choosing types and sizes of the energy storage system for FCHVs.Research in the optimization of hybrid vehicles was predominately conducted independently for either component sizing or control strategy; in rare cases when the two were considered together, control strategies

Bimetallic PtNi nanoparticles have been considered as a promising electrocatalyst for oxygen reduction reaction (ORR) in polymer electrolyte membrane fuel cells (PEMFCs) owing to their high catalytic activity. However, under typical fuel cell operating conditions, Ni atoms easily dissolve into the electrolyte, resulting in degradation of the catalyst and the membrane-electrode assembly (MEA). Here, we report gallium-doped PtNi octahedral nanoparticles on a carbon support (Ga-PtNi/C). The Ga-PtNi/C shows high ORR activity, marking an 11.7-fold improvement in the mass activity (1.24 A mg) and a 17.3-fold improvement in the specific activity (2.53 mA cm) compared to the commercial Pt/C (0.106 A mg and 0.146 mA cm). Density functional theory calculations demonstrate that addition of Ga to octahedral PtNi can cause an increase in the oxygen intermediate binding energy, leading to the enhanced catalytic activity toward ORR. In a voltage-cycling test, the Ga-PtNi/C exhibits superior stability to PtNi/C and the commercial Pt/C, maintaining the initial Ni concentration and octahedral shape of the nanoparticles. Single cell using the Ga-PtNi/C exhibits higher initial performance and durability than those using the PtNi/C and the commercial Pt/C. The majority of the Ga-PtNi nanoparticles well maintain the octahedral shape without agglomeration after the single cell durability test (30,000 cycles). This work demonstrates that the octahedral Ga-PtNi/C can be utilized as a highly active and durable ORR catalyst in practical fuel cell applications.

A high-performance bifunctional Co–P foam catalyst was successfully synthesized by facile one-step electrodeposition at a high cathodic current density.

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Three-dimensional porous Sb/Sb2 O3 anode materials are successfully fabricated using a simple electrodeposition method with a polypyrrole nanowire network. The Sb/Sb2 O3 -PPy electrode exhibits excellent cycle performance and outstanding rate capabilities; the charge capacity is sustained at 512.01 mAh g(-1) over 100 cycles, and 56.7% of the charge capacity at a current density of 66 mA g(-1) is retained at 3300 mA g(-1) . The improved electrochemical performance of the Sb/Sb2 O3 -PPy electrode is attributed not only to the use of a highly porous polypyrrole nanowire network as a substrate but also to the buffer effects of the Sb2 O3 matrix on the volume expansion of Sb. Ex situ scanning electron microscopy observation confirms that the Sb/Sb2 O3 -PPy electrode sustains a strong bond between the nanodeposits and polypyrrole nanowires even after 100 cycles, which maintains good electrical contact of Sb/Sb2 O3 with the current collector without loss of the active materials.

Polymer electrolyte membrane water electrolysis (PEMWE) is the most promising and environmentally friendly method for highly pure hydrogen production when integrated into renewable energy sources. Presently, water electrolysis has merely 4% contribution to global hydrogen production owing to its economic challenges. To reduce the capital and operational cost of PEM water electrolysis, the porous transport layer (PTL) has been investigated intensively in the recent past. A PTL, sandwiched between a catalyst layer and a flow field, is responsible to transport water and oxygen on the anode side as well as hydrogen on the cathode side. In addition to the role of multiphase fluid transportation, PTL also acts as a current collector. A comprehensive insight into PTL materials, structural properties, and their function is strongly required for researchers to enhance performance and reduce the cost of PEMWE system. In this review, we widely discussed the findings on PTL's structural properties, surface modifications, and their impact on enhancing electrochemical performance and durability. In particular, the effect of pore size, porosity, pore gradient, thickness, and pretreatment on ohmic, mass transport, activation overpotential, and PTL modeling has been intensively analyzed. This review will unequivocally increase the previous understanding and open up an avenue for the development of state-of-the-art PTL, thereafter advancing the commercialization of PEMWE.

Exploring cheap and active non-precious metal catalyst for the oxygen reduction reaction (ORR) is a recent major effort in fuel cells for large-scale applications. Herein, we report electrospun cobalt-carbon nanofiber (Co-CNF) as an efficient catalyst for the ORR together with systematic study on active site formation. The ORR activity of Co-CNF increases with increasing Co content up to approximately 30 wt. %, which exhibits high ORR activity comparable with a commercial Pt/C catalyst in alkaline media. XPS and structural analysis reveals a Co-pyridinic N x bond at the edge plane and Co nanoparticles in the Co-CNFs also increase with increasing Co contents. These sites can behave as the primary and the secondary active site for the ORR according to a dual-site mechanism. The ORR activity of Co-CNF may deteriorate even if only one of these sites is limited. The high ORR activity of the Co-CNF catalysts results from the synergetic effect of dual site formation for the ORR. Figure 4. (a) The ORR activity of Co-CNF catalysts with various Co contents and the commercial Pt/C catalysts. (b) H2O2 yield and the electron transfer number of the 32.2 wt. % Co-CNF catalyst in O2-saturated 0.1 M KOH solution at rotating speed of 1600 rpm. ORR activity of (c) 32.2 wt % Co-CNF and (d) 20 wt% Pt/C measured before and after 10,000 voltage cycling from 0.6 to 1.0 V.

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