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This paper presents research on the impact of the material microstructure on the performance of Molten Carbonate Fuel Cells (MCFC). The study is motivated by the need to increase the operation time of MCFC stacks. As the MCFC stacks are mainly composed of porous materials, the paper shows the impact of the porosity on both fuel cell performance and degradation rate. The study is based on the mathematical model, validated through experiments with varying microstructure parameters, achieving an overall relative error of 8%. The study evaluated the performance of MCFC using anodes with different porosity and found that increasing anode porosity from 40% to 70% led to a nearly two-fold increase in maximum power density. However, from both the degradation test and polarization curves, the optimal level of porosity for the anode is around 55%. The porosity level at 55% ensures the highest catalytic surface of the electrodes and is a compromise between the mechanical properties of the electrode and its electrochemical properties. • New approach of 0D model of MCFC including materials microstructure influence is proposed. • The new model is prepared in MS Excel and Aspen HYSYS environments. • Experimental investigation for materials with predefined microstructire parameters was performed for model validation. • Variant analysis is presented for different porosity, tortuosity and constrictivity of MCFC anode. • An optimal scenario is suggested based on modleing results. [ABSTRACT FROM AUTHOR]

Ammonia production via the electrochemical N 2 reduction reaction (NRR) at ambient conditions is highly desired as an alternative to the Haber-Bosch process, but remains a great challenge due to the low efficiency and selectivity caused by the competing hydrogen evolution reaction (HER). Herein we investigate the effect of availabilities of reactants (protons, electrons and N 2) on NRR using a FeO x -coated carbon fiber paper cathode in various electrochemical configurations. NRR is found viable only under the conditions of low proton- and high N 2 availabilities, which are achieved using 0.12 vol% water in LiClO 4 -ethyl acetate electrolyte and gaseous N 2 supplied to the membrane-electrode assembly cathode. This results in an NRR rate of 29 ± 19 pmol NH3 s−1 cm−2 at a Faradaic efficiency of 70 ± 24% at the applied potential of −0.1 V vs. NHE. Other conditions (high proton-, or low N 2 -availability, or both) yield a lower or negligible amount of ammonia due to the competing HER. Our work shows that promoting NRR by suppressing the HER requires optimization of the operational variables, which serves as a complementary strategy to the development of NRR catalysts. • Electrochemical N 2 reduction reaction (NRR) is viable at ambient conditions. • Electrochemical system with membrane-electrode assembly yields best NRR activity. • NRR is promoted at the condition of low proton- and high-N 2 availabilities. • High proton-, or low-N 2 availabilities or both favor H 2 evolution side reaction. [ABSTRACT FROM AUTHOR]

In this study, in-situ cerium-assembled tungsten oxide carbon nanofibers were successfully prepared via simple electrospinning and calcination technology and were used as flexible electrodes without conductive agent and adhesive. It was confirmed that the introduction of Ce has better maintained the continuous morphology of one-dimensional fibers to provide a continuous uninterrupted reaction position by the SEM TEM and XPS results. The addition of cerium improved the wettability of the material, which was propitious to the penetration of the electrolyte, made the electrolyte more fully contact with the active site, and enhanced the interface transmission effectiveness by the liquid contact angle test. Otherwise, the XRD and XPS results exhibited that the addition of cerium has caused the lattice expansion of the tungsten oxide, which generated the self-adjustable strain relaxation ability of electrode material in the process of continuous constant voltage charge and discharge. It proved that the introduction of cerium has promoted electron transfer, which improved the electrochemical performance of electrode material. In this paper, compared with WO 3 -CNFs without Ce, the Ce/WO 3 -CNFs have wide lattice spacing and hydrophilicity, fully contact with the electrolyte in the electrochemical reaction, and provide high electron transfer ability. The Ce/WO 3 -CNFs shows the maximum specific capacitance (407 F g−1) and excellent cycling stability (10,000 cycles at 5 A g−1 with a retention rate of 80 %). Otherwise, the flexible asymmetric supercapacitor device was prepared using the Ce/WO 3 -CNFs as cathode, and the CNFs as the anode, which exhibited the maximum energy density was 35.75 Wh kg−1 and a power density was 362.54 W kg−1 at 0.5A g−1. The results show that rare earth doping is an effective way and that the Ce/WO 3 -CNFs are promising electrode materials for supercapacitors. For the first time, in-situ cerium-assembled tungsten oxide carbon nanofibers were successfully prepared via simple electrospinning and calcination technology, which could directly serve as a flexible electrode without conductive agent and adhesive. And then, the flexible solid-state asymmetric supercapacitor was prepared using the Ce/WO 3 -CNFs as the cathode, the CNFs as the anode, and a PVA/KOH gel as electrolytes. [Display omitted] • The Ce/WO 3 -CNFs is used as binder-free electrode for supercapacitor. • Cerium improves the electrochemical performance of WO 3. • The improvement of electrode material wettability promotes the transportation of ions and electron between electrode and electrolyte. [ABSTRACT FROM AUTHOR]

The uniform coating of catalytic materials on the electrode surface is essential for improving the performance of electrochemical reactions. In this study, the electrostatic spray coating technique is used to deposit Molybdenum disulfide (MoS 2) particles on carbon electrodes and examine the electrochemical hydrogen evolution reaction (HER) performance in a 0.1 M H 2 SO 4 electrolyte. The experimental results reveal that the electrostatic spray coating method achieves a more uniform coating MoS 2 catalyst particles on the carbon fiber substrate. It provides good adhesion for electrocatalyst binding on the carbon paper electrodes. During HER analysis, a 25% higher current density is obtained from the electrostatic spray-coated electrodes compared to the manual spray-coated electrode at a potential of 0.95 V. Electrochemical impedance spectroscopy, and electrochemical surface area measurements indicate the superior electrochemical characteristics of the electrostatic spray-coated electrode. The faradaic efficiency of the electrostatic spray-coated electrode is close to 100% at a high applied potential of −1.6 V with a 0.0059 L volume of hydrogen generation. Moreover, chronoamperometric measurements demonstrate the excellent durability of the electrostatic spray-coated carbon electrodes. This study suggests that the facile electrostatic spray method is efficient for coating electrodes with high uniformity and good adhesion for various electrochemical applications. • The parametric study and its results verify the relevant coating method for HER process. • The electrostatic spray is the efficient method, exhibits high uniformity and good adhesion. • The electrostatic spray-coated electrodes delivered higher current density than manual spray-coated electrodes. • The electrostatic spray provides 100% faradaic efficiency at −1.6 V. [ABSTRACT FROM AUTHOR]

In this paper, we have synthesized a nanocomposite of nickel oxide (NiO) and cobalt oxide (Co 3 O 4) using l -ascorbic acid which is named A(NC). Herein, A stands for l -ascorbic acid, N stands for nickel oxide (NiO), and C stands for cobalt oxide (Co 3 O 4). Where l -ascorbic acid has been used as stabilizing agent/capping agent. Herein, a simple two steps wet-chemical method has been used for the synthesis of the nanocomposite A(NC). This synthesized nanocomposite has been characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), powder X-ray diffraction (PXRD), X-ray photoelectron spectroscopy (XPS), UV–visible spectroscopy, and Fourier transform infrared spectroscopy (FTIR). A comparative electrochemical study has been done using cyclic voltammetry (CV) and galvanostatic charge/discharge (GCD) techniques for supercapacitor performance. This study has been performed with a three-electrode system using 1 M Na 2 SO 4 as a supporting electrolyte. Herein, a glassy carbon electrode (GCE) as a working electrode, Ag/AgCl as a reference electrode and Pt electrode as a counter electrode have been used in the electrochemical analysis. The CV curves have been recorded at different scan rates of 5 mV/s, 10 mV/s, 15 mV/s, 20 mV/s, 40 mV/s, 80 mV/s, and 100 mV/s respectively. The value of specific capacitance has been calculated 2.1472 F/g at 5 mV/s and energy density at 0.1074 Wh/kg using the CV curves. Whereas, specific capacitance and energy density have been determined 0.6833 F/g and 0.0342 Wh/kg respectively using the GCD method. Also, the photocatalytic degradation behavior of the synthesized nanocomposite A(NC) has been investigated against methylene blue (MB) dye. Herein, 89.88% MB dye has been degraded with synthesized nanocomposite A(NC) within 360 min in the presence of sunlight. [Display omitted] • Ascorbic acid-mediated NiO/Co 3 O 4 named A(NC) has been synthesized by the two-step wet chemical method for the first time. • The characterization has been done by UV–Visible spectroscopy, FT-IR, PXRD, XPS, SEM, and EDS analysis. • Sheets with 'nanosize cracks' of as-synthesized NiO/Co 3 O 4 have been obtained. • NiO/Co 3 O 4 has been used for the effective degradation (89.88%) of methylene blue under sunlight. • Electrochemical study has been done using CV and GCD techniques for supercapacitor performance. [ABSTRACT FROM AUTHOR]

The development of large surface-area and high conductivity electrode is a prerequisite for the construction of high-performance microbial fuel cells. Herein, we report an innovative approach to the fabrication of such high-performance electrodes via the welding assembly of 3D interconnected carbon nanotubes (CNTs) on a carbon-fiber (CF) paper electrode. The minimized interfacial ohmic loss between CNTs and the CF scaffold endowed the microbial fuel cells with the welding-assembled CNT-CF electrodes excellent electrochemical properties with the maximum power density of 2015.6 mW m−2, 10.0 times higher than that obtained with the untreated CP/CNT (499.8 mW m−2) carbon paper anode. As compared to the conventional chemical vapor deposition (CVD) growth technique for fabricating CNT- CF electrodes, this welding assembly approach is more versatile and much easier for up-scaling; on this basis, our work may pave a new avenue to the large-scale production of high-performance microbial fuel cells. • A novel approach to fabricating 3D welding-assembled CNT-CF electrodes for MFC. • Formation of robust network by welding assembly of the interconnected CNTs. • A modified anode providing the power density of MFC 10 times higher than CP. [ABSTRACT FROM AUTHOR]

In the paper, MOF(Ni) and MOF(Ni) complex with graphene MOF(Ni)-GR(w%) are synthesized by solvothermal method. The structure, morphology and elemental composition of samples are analyzed by physical characterization such as SEM, XRD, EDS and XPS. The results show that MOF(Ni) and MOF(Ni)-GR(w%) with high crystallinity and less impurities are successfully synthesized. Different samples are loaded on the electrodes and their electrochemical performances are tested by electrochemical workstation. The results show that doping appropriate graphene in MOF(Ni) can effectively improve the electrochemical catalytic activity of the composites. When the content of graphene is 4%, MOF(Ni)-GR(4%) is of the highest electrochemical catalytic activity, its overpotential is 268 mV, the Tafel slope is 108 mV·dec−1, and it has better electrochemical stability compared with that of Pt/C electrode. The ECSA and EIS of MOF(Ni)-GR(4%) are superior to that of MOF(Ni) in exploring the reasons for enhancing catalytic hydrogen evolution. The reason is that the addition of graphene enhances the conductivity of the composites and reduces the resistance of catalyst transportation. Moreover, the doping of graphene improves the specific surface area of the composites, and provides enough active sites for hydrogen evolution reaction (HER). [Display omitted] • MOF(Ni) and MOF(Ni)-GR(w%) composites were prepared by solvothermal method. • MOF(Ni)-GR(4%) material has good electrocatalytic activity for HER. • MOF(Ni)-GR(4%) has better electrochemical stability compared with Pt/C electrode. [ABSTRACT FROM AUTHOR]

In this work, we report the significant enhancement of the electrochemical performance and flexibility of a lithium–oxygen battery by introducing a free-standing, binder-free carbon nano-fibers (CNF) grafted carbon paper cathode with a bimodal pore architecture. The small pore structures (∼100 nm) accommodated Li 2 O 2 , and the large pore structures (∼10 μm) enabled effective oxygen diffusion without clogging the pores. This kind of cathode overcame some troubles of the cathode prepared by spraying coating method, such as the low utilization of substrate surface, the unreasonable aperture structure and the aggregation of active carbon material. As a result, this electrode structure imparted stability to active sites during the recovery of discharge products to the initial state, providing long-term cyclability of more than 800 cycles in a 1 M LiTFSI/TEGDME electrolyte system. In addition, the battery output a discharge capacity as high as 20000 mAh g −1 at 468 mA g −1 and exhibited a charge/discharge rate as high as 1136 mA g −1 (0.57 mA cm −2 ). The test results suggest that these CNF-grafted carbon papers have the potential to be used for oxygen/air electrodes for next-generation lithium-oxygen batteries, though the present results need to be improved to achieve performance of practical significance, namely with regard to (i) cathode mass loading to get higher areal capacity, and (ii) cycling performance at higher current density. [ABSTRACT FROM AUTHOR]

This paper carefully evaluates the electrocatalytic activity of Sr 2 FeMo 0.5 Mn 0.5 O 6 (SFMM) double perovskite as a candidate to substitute the state-of-the-art Ni/YSZ fuel electrode. The electrochemical performance of a 40% SFMM/CGO composite electrode was studied in CO/CO 2 and H 2 with different oxygen partial pressure. Two different cell configurations are prepared at a relatively low temperature of 800 °C to increase the electrochemically active surface area. The cell was supported with a 150 μm 10Sc1CeSZ electrolyte in the first configuration. The cell in the second configuration was made by applying a 400 nm thin 8YSZ layer on 150 μm CGO electrolyte to improve the electrolyte ionic conductivity. Improving catalytic activity with increasing oxygen partial pressure is a key characteristic of the developed electrode. The polarization resistance of about 0.34 and 0.56 Ω cm2 at 750 °C in 3%H 2 O + H 2 and 60% CO/CO 2 makes this electrode a promising candidate for SOCs application. • A crack-free SFMM/CGO composite fuel electrode prepared at 800 °C without the formation of the SrZrO 3 insulator phase. • The SFMM double perovskite shows a stable structure at high oxygen partial pressure. • The electrochemical behavior obtained in CO/CO 2 and H 2 with 3–20 vol% H 2 O. • The relatively small polarization resistance makes it a candidate for substitution of the state-of-art Ni/YSZ electrode. [ABSTRACT FROM AUTHOR]

Facile synthesis methods and rich-reserve feedstocks are the keys to accelerating the scale commercial use of Sb-based anodes for sodium-ion batteries (SIBs). In this paper, we synthesize Sb/carbon nanotubes (CNTs) composite anodes by a straightforward electrochemical approach using stibnite and CNTs as feedstocks. The concentrated sodium hydrate solution profits the formation of antimony and electrons enables the solid-state electrochemical desulfurization. The low-cost stibnite can be directly obtained from the earth's crust avoiding the intermediate processes and pollution of preparing the common-used raw materials SbCl 3 and metallic Sb. CNTs provides a network for both electron and ion transport, thereby resulting in producing Sb particles anchored in the CNTs network as well as restraining the cluster of electrolytic Sb particles. The electrolytic Sb-0.5CNTs anode delivers a decent capacity of 510 mAh g−1 at 0.1 A g−1 after 200 cycles and even 425 mAh g−1 at 1 A g−1 over 100 cycles. The excellent sodium-storage performances are attributed to the unique structure of the electrolytic Sb/CNTs composite. This electrochemical desulfurization method can be expanded to prepare other metal-carbon type anodes from metal sulfides ores and carbon materials composites. [Display omitted] • Sb/CNTs composites are synthesized via a facile strong alkali electrolysis. • Earth-abundant stibnite is employed as feedstock and electrons as reducing agents. • CNT buffer can facilitate the transport of ions and electrons. • The Sb/CNTs composites anodes have high cycling and rate capability for SIBs. [ABSTRACT FROM AUTHOR]

Direct carbon solid oxide fuel cells (DC-SOFCs) are promising energy-conversion devices that can directly convert the chemical energy of carbon into electricity with high efficiency and low pollution. The efficient and durable operation of DC-SOFCs is maintained by the effective coupling of electrochemical oxidation in the anode and the reverse Boudouard reaction in the carbon fuel. In this paper, we review recent advances in material design, fuel development, and heat management for improving the electrochemical output and conversion efficiency of DC-SOFCs. First, developments in state-of-the-art anode materials for the electrochemical oxidation of carbon are briefly reviewed. Second, various kinds of carbon fuels and catalysts for carbon gasification are outlined. Third, we introduce the present status of heat management in DC-SOFC systems. Finally, some conclusions involving challenges in DC-SOFCs and perspectives on them are systematically summarized. • A comprehensive review of the advanced progress on DC-SOFCs is given. • State-of-the-art anode materials development for DC-SOFCs is reviewed. • The catalysts of carbon gasification and alternative carbon fuels are presented. • Current situations of the heat management for DC-SOFCs are introduced. • Critical challenges and perspectives of DC-SOFCs are proposed and summarized. [ABSTRACT FROM AUTHOR]

This paper explores the potential of using solid-state electrochemical heat engines (EHE) operating on reversible redox reactions to generate electric power using available thermal energy from natural and man-made sources. Electrochemical heat engines utilize and control the electrochemical potential of molecules undergoing redox reactions in a manner to produce electrical energy from thermal energy. The electrochemical potential of these redox pairs is a function of composition, temperature and pressure. EHE's in this paper exploit the change in basic thermodynamic properties with temperature. The EHE technology can be deployed using fuel cell and electrolyser combinations. It is quite interesting that for mature optimized EHE systems there is great potential for energy harvesting. [ABSTRACT FROM AUTHOR]

The present paper reports the data on the long-term monitoring (during 1500 h at 800 °С in the atmosphere of wet hydrogen and 40% H 2 + 60% H 2 O) of Ni–Zr 0.9 Sc 0.1 O 1.95 anode polarization resistance before and after its impregnation with cerium oxide. In wet hydrogen difference between the rates of polarization resistance degradation before and after impregnation is insignificant and reaches a level close to stationary one after 500 h of testing. In 40% H 2 + 60% H 2 O gas mixture a behavior of the initial anode is similar to the above mentioned, whereas, the high rate of increase the polarization resistance of impregnated anode and sintering cerium oxide species was observed. After the long-term tests, the re-impregnation allows increasing the anode activity. The re-impregnation of anode increases its activity the higher, the greater of anode degraded during the long-term tests. [ABSTRACT FROM AUTHOR]

Over the last few years, we have developed a 1.3 kW direct methanol fuel cell (DMFC) system with a proven lifetime of 20,000 h. An extension of the system's lifetime would dramatically increase the commercial competitiveness of this technology. In order to reduce degradation effects in the stack, we identify the insertion of ion exchange filters into the anodic circuit as an important approach for absorbing impurities directly in the fluid cycle. This paper outlines the development of a characterization technique and material screening process for ion exchange materials, which are characterized in terms of their stability, activity and capacity, as well as their selectivity under the operating conditions of a DMFC system. The amount of ion-exchanging material is calculated by means of a project post-mortem analysis of a DMFC stack operated for 20,000 h. This study fills a gap in the literature and offers a basis for the designing of ion exchangers. The results presented are an important step for the ongoing development process and commercial deployment of DMFC systems. Given the similarity of requirements, the results are also applicable to the PEM electrolysis field. [ABSTRACT FROM AUTHOR]

This paper describes a high efficiency photoelectrochemical electrode, i.e., TiO 2 /CdS/ZnIn 2 S 4 nanorod-nanosheet arrays (NRSs) for photoelectrochemical water splitting. On the basis of optimal quantity of ZnIn 2 S 4 nanosheets and optimal thickness of CdS buffer layer, the as-prepared TiO 2 /CdS/ZnIn 2 S 4 NRSs exhibit a higher photoelectrochemical performance, the photocurrent density reaches 9.33 mA cm −2 at 0.53 V versus Ag/AgCl. The superior performance observed over this TiO 2 /CdS/ZnIn 2 S 4 NRSs can be ascribed to a higher efficiency of light-harvesting ability, ideal energy band alignment, accelerated charge transmission and increased chemical stability. This study opens up a new available way to design and construct photoelectrodes for photoelectrochemical water splitting and other solar conversion materials. [ABSTRACT FROM AUTHOR]

In order to reduce the effect of water flooding on larger active area of Proton Exchange Membrane Fuel cell (PEMFC), an enhanced flow distribution on the flow channel is mandatory. In this paper to mitigate the water flooding problem, experimental studies have been carried out on 25 cm 2 and 70 cm 2 active area of PEMFCs with various flow channel designs on the cathode flow plate namely serpentine, uniform and zigzag pin type; and flow channel with 2 mm cubical porous inserts on the uniform and zigzag pin types. The results show that the cathode flow field plate with zigzag positioned porous carbon inserts having 80–90% porosity has improved the current and power densities by 7% and 11.5% respectively, when compared to the conventional serpentine flow field plate for 25 cm 2 PEMFC. The above procedure has been followed for scaling up studies from 25 cm 2 to 70 cm 2 PEMFCs for effective water management. It is concluded that the 70 cm 2 PEMFC with zigzag positioned porous carbon inserts on the cathode flow field has increased the current and power densities by 8.7% and 20.6% respectively compared to the conventional serpentine flow field. The porous carbon inserts on the rib surface of the cathode flow field removes the accumulated liquid water from the rib surface through the capillarity of its porous structure, due to this the performance of PEMFC is enhanced in scaling-up studies with better water transport characteristics. [ABSTRACT FROM AUTHOR]

In this paper, Sr 2 Fe 1.5 Mo 0.4 Nb 0.1 O 6−δ (SFMNb)−xSm 0.2 Ce 0.8 O 2−δ (SDC) (x = 0, 20, 30, 40, 50 wt%) composite cathode materials were synthesized by a one-pot combustion method to improve the electrochemical performance of SFMNb cathode for intermediate temperature solid oxide fuel cells (IT-SOFCs). The fabrication of composite cathodes by adding SDC to SFMNb is conducive to providing extended electrochemical reaction zones for oxygen reduction reactions (ORR). X-ray diffraction (XRD) demonstrates that SFMNb is chemically compatible with SDC electrolytes at temperature up to 1100 °C. Scanning electron microscope (SEM) indicates that the SFMNb-SDC composite cathodes have a porous network nanostructure as well as the single phase SFMNb. The conductivity and thermal expansion coefficient of the composite cathodes decrease with the increased content of SDC, while the electrochemical impedance spectra (EIS) exhibits that SFMNb-40SDC composite cathode has optimal electrochemical performance with low polarization resistance ( R p ) on the La 0.9 Sr 0.1 Ga 0.8 Mg 0.2 O 3 electrolyte. The R p of the SFMNb-40SDC composite cathode is about 0.047 Ω cm 2 at 800 °C in air. A single cell with SFMNb-40SDC cathode also displays favorable discharge performance, whose maximum power density is 1.22 W cm −2 at 800 °C. All results indicate that SFMNb-40SDC composite material is a promising cathode candidate for IT-SOFCs. [ABSTRACT FROM AUTHOR]

The designs of flow channels are highly influencing the performance of PEMFC. A serpentine flow channel with Uniform and Zigzag positioned porous carbon inserts on cathode flow plate is experimentally analyzed in this paper. Addressing the flooding problem, a single PEMFC having an active area of 25 cm 2 with various flow channel designs on the cathode flow plate namely serpentine, uniform and zigzag pin type; and flow channel with 2 mm cubical porous inserts on the uniform and zigzag pin type is experimentally investigated. The influence of porosity of carbon inserts on the cell performance is also studied by varying the porosity of carbon inserts in the range of 60–70%, 70–80%, 80–90% respectively. The results show that the flow channel with zigzag positioned porous inserts having 80–90% porosity has improved the power density and current density by 11.5% and 7% respectively when compared to the conventional serpentine flow channel. The reason for the increase in such performance is that, the porous insert on the rib surface removes the accumulated liquid water from the rib surface through the capillarity of its porous structure and eliminates the stagnant regions under the rib, thereby reducing liquid flooding in the interface between rib and GDL. [ABSTRACT FROM AUTHOR]

Direct-fired fuel cell gas turbine hybrid power system responses to open-loop transients were evaluated using a hardware-based simulation of an integrated solid oxide fuel cell gas turbine (SOFC/GT) hybrid system, implemented through the Hybrid Performance (Hyper) facility at the U.S. Department of Energy, National Energy Technology Laboratory (NETL). A disturbance in the cathode inlet air mass flow was performed by manipulating a hot-air bypass valve implemented in the hardware component. Two tests were performed; the fuel cell stack subsystem numerical simulation model was both decoupled and fully coupled with the gas turbine hardware component. The dynamic responses of the entire SOFC/GT hybrid system were studied in this paper. The reduction of cathode airflow resulted in a sharp decrease and partial recovery of the fuel cell thermal effluent in 10 s. In contrast, the turbine rotational speed did not exhibit a similar trend. The transfer functions of several important variables in the fuel cell stack subsystem and gas turbine subsystem were developed to be used in the future control method development. The importance of the cathode airflow regulation was quantified through transfer functions. The management of cathode airflow was also suggested to be a potential strategy to increase the life of fuel cells by reducing the thermal impact of operational transients on the fuel cell subsystem. [ABSTRACT FROM AUTHOR]

Under ultra-low fuel stoichiometry condition, direct methanol fuel cell (DMFC) suffers from severe methanol crossover in the inlet region and methanol shortage in the outlet region, which results in significant performance drop. In order to improve uniformity of fuel distribution, this paper proposes an anode structure which has a dead-end fuel chamber with a porous fuel distributor, so called interdigitated anode. Comparative study between the conventional cell and the interdigitated cell was conducted with multi-dimensional model. Calculation result shows the interdigitated structure mitigates anode non-uniformity by switching fuel transport mechanism from diffusion to convection, which leads to enhancement of both cell voltage and fuel efficiency. [ABSTRACT FROM AUTHOR]

Bio-cathode which uses microorganisms as catalyst can reduce MFC cost and sustain similar power output compared to noble metal catalyst. Thereby, looking for a cathode material which is high conductivity, good biocompatibility and even can stimulate and enhance activity of bio-catalyst is of great interest. In this paper, modified electrode by tourmaline and polyaniline (reactor 3) was used as cathode. The output power density was improved by 492.6% and 192.8% compared to reactor 1 (unmodified cathode) and reactor 2 (cathode modified only by polyaniline) (54 mW m−2 for reactor 1, 138 mW m−2 for reactor 2 and 266 mW m−2 for reactor 3, respectively). When the external resistance was 800Ω, output voltages of reactor 1, 2 and 3 were kept at 0.20 ± 0.005 V, 0.26 ± 0.005 V and 0.37 ± 0.005 V, respectively. Cyclic voltammetry curves showed that reductive current of reactor 3 was higher than those of reactor 1 and 2, indicating that the cathode of reactor 3 had the strongest catalytic activity which was due to that tourmaline could help the interfacial electron transfer, and thereby facilitate the reduction of oxygen at the cathode. Results demonstrated that the tourmaline modified electrode could effectively improve the reduction reaction and enhance the performance of the whole MFC system. [ABSTRACT FROM AUTHOR]

Abstract: The present paper shows the preparation and characterization of alkaline batteries cathodes formed by nickel hydroxide with the addition of cobalt. This additive was incorporated by two methods: on the electrode surface, using the electroless technique and by direct incorporation of cobalt powder in the active material. The electrochemical behavior of both nickel hydroxide electrodes was investigated and compared. The results indicate that active materials containing cobalt additive by the electroless technique exhibit an improvement on the electrochemical performance. [Copyright &y& Elsevier]

Abstract: The paper reports the use of alkaline sulfide as a fuel with advantages of low cost, easy storage and transportation, and high electrochemical activity. The fuel cell fueled with alkaline sulfide, named direct alkaline sulfide fuel cell (DASFC), oxidizes sulfide to sulfur oxyanion without electrochemical catalyst, allowing not only to remove H2S but also to fully recover energy stored in H2S as electricity. In this study, particular attention was paid to systematic investigation of the effects of various operating parameters on cell performance, such as NaOH concentration, sulfide concentration, temperature, and electro-catalyst. Higher alkalinity and sulfide concentration of the anolyte were found to lead to higher power output, recording maximum power density of 10.69 mW cm−2 at 1.0 M sulfide, 3.0 M NaOH, and 80 °C, which greatly increased up to 25.86 mW cm−2 with the aid of Pt/C. During discharge, DASFC with higher alkaline anolyte exhibited higher current density profile, resulting in more oxidized sulfur oxyanions to be dominant. In the SEM analysis, the anode surface after discharge did not show any distinctive change from the original state, indicating that the anode of DASFC is free from sulfur deposition even at ambient temperature. Considering electricity generation, recovery of sulfur oxyanion, and long-term stability, we tend to believe that DASFC is one sustainable, promising way of tackling H2S problem. [Copyright &y& Elsevier]

Among the electrode materials of supercapacitors, transition metal oxides have been widely used because of their low price, high theoretical capacitance and good cycle stability, and MnO 2 is one of the typical representative materials. However, the actual specific capacitance of MnO 2 is low because of its poor conductivity, easy agglomeration in the preparation process and large volume change in the process of repeated charge and discharge. Attapulgite can not only provide a large specific surface area for transition metal oxide materials, but also provide a skeleton on which nano-sized materials can be grown or dispersed. Therefore, the electrochemical performance of electrode materials can be improved by designing nanostructures and compounding a variety of materials with different properties. Herein, a new type of composites electrode material is prepared by simple one-step hydrothermal method. As an electrode material, the ATP-MnO 2 composites exhibited a high specific capacitance of 138.2 F/g at a current density of 0.5 A/g, which was 13.4% higher than that of pure MnO 2 nanoflowers. Under the current density of 3 A/g, the capacitance retention of ATP-MnO 2 composites was 89.4% after 5000 cycles. • Provides a new idea for the application of clay-based materials in electrochemistry. • Composites can be prepared by a simple hydrothermal method. • Attapulgite can disperse the agglomeration of MnO 2 and improve the adsorption. • The capacitance and cyclic stability of the composites can be improved by attapulgite. [ABSTRACT FROM AUTHOR]