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1.
Multi-anode/cathode microbial fuel cells (MFCs) incorporate multiple MFCs into a single unit, which maintain high power generation at a low cost and small space occupation for the scale-up MFC systems. The power production of multi-anode/cathode MFCs was similar to the total power production of multiple single-anode/cathode MFCs. The power density of a 4-anode/cathode MFC was 1184 mW/m3, which was 3.2 times as that of a single-anode/cathode MFC (350 mW/m3). The effect of chemical oxygen demand (COD) was studied as the preliminary factor affecting the MFC performance. The power density of MFCs increased with COD concentrations. Multi-anode/cathode MFCs exhibited higher power generation efficiencies than single-anode/cathode MFCs at high CODs. The power output of the 4-anode/cathode MFCs kept increasing from 200 mW/m3 to 1200 mW/m3 as COD increased from 500 mg/L to 3000 mg/L, while the single-anode/cathode MFC showed no increase in the power output at CODs above 1000 mg/L. In addition, the internal resistance (Rin) exhibited strong dependence on COD and electrode distance. The Rin decreased at high CODs and short electrode distances. The tests indicated that the multi-anode/cathode configuration efficiently enhanced the power generation.  相似文献   

2.
To screen out suitable electrode materials and overcome the shortcomings of the existed electrode materials for the application in dye-sensitized solar cells and supercapacitors, NiS2/reduced graphene oxide (NiS2/rGO) composite material was prepared by a simple one-step hydrothermal method in this paper and applied in the field of both dye-sensitized solar cells and supercapacitors as electrode material. In an electrolyte of 6 M KOH, the NiS2/rGO composite material with bilayer capacitance characteristics exhibited a high specific capacitance of 259.20 F g−1 at the current density of 0.6 A g−1, which was significantly higher than that of rGO (188.94 F g−1). Moreover, at a current density of 2 A g−1, the NiS2/rGO composite material had 92.85% capacitance retention after 2000 cycles. When applied as counter electrode material for the dye-sensitized solar cells, the NiS2/rGO composite material counter electrode exhibited a satisfactory photoelectric conversion efficiency (η) of 3.16% under standard simulated sunlight (AM 1.5 G), which was significantly higher than that of single rGO counter electrode (improved by 90.40%). The NiS2/rGO composite electrode material prepared by a simple one-step hydrothermal method is a potential bi-functional composite electrode materials for both dye-sensitized solar cells and supercapacitors.  相似文献   

3.
Carbon-based materials are the most commonly used electrode material for anodes in microbial fuel cell (MFC), but are often limited by their surface areas available for biofilm growth and subsequent electron transfer process. This study investigated the use of activated carbon nanofibers (ACNF) as the anode material to enhance bacterial biofilm growth, and improve MFC performance. Qualitative and quantitative biofilm adhesion analysis indicated that ACNF exhibited better performance over the other commonly used carbon anodes (granular activated carbon (GAC), carbon cloth (CC)). Batch-scale MFC tests showed that MFCs with ACNF and GAC as anodes achieved power densities of 3.50 ± 0.46 W/m3 and 3.09 ± 0.33 W/m3 respectively, while MFCs with CC had a lower power density of 1.10 ± 0.21 W/m3 In addition, the MFCs with ACNF achieved higher contaminant removal efficiency (85 ± 4%) than those of GAC (75 ± 5%) and CC (70 ± 2%). This study demonstrated the distinct advantages of ACNF in terms of biofilm growth and electron transport. ACNF has a potential for higher power generation of MFCs to treat wastewaters.  相似文献   

4.
Self-stratifying microbial fuel cells with three different electrodes sizes and volumes were operated in supercapacitive mode. As the electrodes size increased, the equivalent series resistance decreased, and the overall power was enhanced (small: ESR = 7.2 Ω and Pmax = 13 mW; large: ESR = 4.2 Ω and Pmax = 22 mW). Power density referred to cathode geometric surface area and displacement volume of the electrolyte in the reactors. With regards to the electrode wet surface area, the large size electrodes (L-MFC) displayed the lowest power density (460 μW cm−2) whilst the small and medium size electrodes (S-MFC, M-MFC) showed higher densities (668 μW cm−2 and 633 μW cm−2, respectively). With regard to the volumetric power densities the S-MFC, the M-MFC and the L-MFC had similar values (264 μW mL−1, 265 μW mL−1 and 249 μW cm−1, respectively). Power density normalised in terms of carbon weight utilised for fabricating MFC cathodes-electrodes showed high output for smaller electrode size MFC (5811 μW g−1-C- and 3270 μW g−1-C- for the S-MFC and L-MFC, respectively) due to the fact that electrodes were optimised for MFC operations and not supercapacitive discharges. Apparent capacitance was high at lower current pulses suggesting high faradaic contribution. The electrostatic contribution detected at high current pulses was quite low. The results obtained give rise to important possibilities of performance improvements by optimising the device design and the electrode fabrication.  相似文献   

5.
A novel nanoblocks@nanoballs NiMnO3/Ni6MnO8 electrode material was synthesized by one-step solvothermal–hydrothermal method, followed by thermal annealing. At the same time, electrode materials with different nanostructure were prepared by changing the volume ratio of deionied water and ethylene glycol. The results show that different structure has been gained including nanospheres, nanosheets and nanoblocks. When the deionied water: ethylene glycol = 1:1 (nanoblocks@nanoballs NiMnO3/Ni6MnO8 composite structure), the electrode material has a maximum specific surface area of 55.3 m2 g−1. The electrode material exhibited outstanding electrochemical performance with specific capacitance reached 494.4 F g−1 at a current density of 1 A g−1 as well as superior cycling performance of 88.0% capacitance retention after 5000 cycles at 3 A g−1. Such excellent performance was due to the synergistic effective between the Ni6MnO8 nanoballs and NiMnO3 nanoblocks. Nanoballs structure will increase in specific surface area and redox reaction active sites, and the blocks structure acts as a holder to improved the cycle performance. The NiMnO3/Ni6MnO8 become a promising candidate as next-generation electrode material for high-performance supercapacitors.  相似文献   

6.
The demands for highly efficient and low-cost electrochemically active materials are still urgent needs for the fields of electro-catalysis and supercapacitor. Herein, a facile strategy for preparing high-efficient bi-functional electrode material was reported. The electrode material was prepared through embedding Co2P nanoparticles in the binary co-doped carbon nanofibers (Co2P@N&P-CNFs). This unique structure can effectively prevent the Co2P from detaching and provide abundant active sites. Materials prepared in this work showed the superior hydrogen evolution reaction (HER) performance with overpotential of 192 mV at a current density of 10 mA cm?2 and remarkable stability for 20 h. Moreover, the asymmetric supercapacitor (ASC) was fabricated using the Co2P@N&P-CNFs as the positive electrode material and carbon nanofibers (CNFs) as the negative electrode material, which shows an outstanding cycle stability (91.5% of the initial capacitance is retained throughout 10,000 charge-discharge tests) and a high E of 22.31 Wh kg?1 at the P of 225.02 W kg?1 at 0.3 A g?1. This work offers an effective route in designing bi-functional active materials for HER and supercapacitor.  相似文献   

7.
This study assessed the feasibility of vanadium pentoxide (V2O5) as a novel cathode catalyst material in air-cathode single chamber microbial fuel cells (SCMFCs). The V2O5 nanorod catalyst was synthesized using a hydrothermal method. MFCs with different cathode catalyst loadings were studied. Cyclic voltammetry (CV) was used to examine the electrochemical behavior of the catalysts in the MFCs. The V2O5 cathode catalyst constructed with a double loading MFC exhibited the highest maximum power density of 1073 ± 18 mW m−2 (OCP; 691±4 mV) compared with 447 ± 12 mW m−2 (OCP; 594 ± 5 mV) and 936 ± 15 mW m−2 (OCP; 647±5 mV) for the single loading MFC and triple loading MFC, respectively. The power density of MFC with double loaded V2O5 is comparable to the traditional Pt/C cathode (2067 ± 25 mW m−2, OCP; 821 ± 4 mV), which covers up to 55% of the performance of Pt/C. This finding highlights the potential of the V2O5 cathode as an inexpensive catalyst material for MFCs that may have commercial applications.  相似文献   

8.
The intent of designing and exploring novel active electrode materials is to enhance the electrochemical performance of supercapacitors. Herein, a hierarchical structure of nickel-cobalt-sulfide nanostructures (NiCo2S4) decorated on the electrospun N-doped carbon nanofiber (CNF), NiCo2S4@CNF, is manipulated using a one-step and simple hydrothermal approach. The fabricated hierarchical structure of the NiCo2S4@CNF is featured by a large surface area and a high porosity that serve as ion diffusion channels. Therefore, it manifests high specific capacitance and specific capacity values of 377.2 C g?1 and 754.4 F g?1 at a current density of 1 A g?1, respectively. Furthermore, a NiCo2S4@CNF//CNF hybrid supercapacitor in which a positive electrode of NiCo2S4@CNF is assembled with a negative electrode of CNF to estimate the electrochemical performance of the NiCo2S4@CNF. As a result, the device has a superior energy density of 65.6 and 52.5 Wh kg?1 at a power density of 665 and 1313.8 W kg?1, respectively. Moreover, the device reveals good stability with capacitance retention of 72% after 3000 charge/discharge cycles. These outstanding results enable the designed hierarchical structure of the NiCo2S4@CNF to be a promising electrode material for supercapacitors (SCs) applications.  相似文献   

9.
The nanoparticles of Mn1.5[Cr(CN)6]∙mH2O@Ni1.5[Cr(CN)6]∙nH2O core-shell prussian blue analogues (PBA) embedded with carbon additives (PBA-C) were synthesized and characterized as electrode material for solid state battery application. The impedance spectroscopy and cyclic voltametry were used to study the electrochemical properties by adding functionalized carbon in 1:1 proportion to improve the electrical performance. The value of room temperature electrical conductivity of core-shell PBA and core-shell nanoparticles mixed with vulcan carbon (PBA-C) are found to be 1.574 × 10−3 and 1.92 × 10−3 Scm−1, respectively. Using Li7La3Zr2O12 (LZZO) electrolyte, single cell was fabricated with PBA-C material, and studied its charging-discharging cycles, which exhibits higher current density with stable performance for 400 cycles for time slots of 400 min. The study reveals that the PBA core-shell nanoparticles mixed with carbon (PBA-C) may be a potential candidate as an electrode material in the form of a single cell using LZZO electrolyte.  相似文献   

10.
Direct CO2 electrolysis has been explored as a means to store renewable energy and produce renewable fuels. La chromate-based perovskite oxides have attracted great attention as fuel electrode materials for solid oxide electrolyzer cells. However, the electrochemical catalytic activity of such oxides is relatively low, and their stability has not been confirmed. In this study, Pr is doped into La0.75Sr0.25Cr0.5Mn0.5O3-δ (LSCM) and the applicability of the resulting fuel electrode to direct CO2 electrolysis is investigated. The polarization resistance of the resulting electrode at 800 °C is decreased by 25%. Distribution function of relaxation times analysis indicates that the observed improvements may be attributed to increased oxygen ion conductivity. A full cell of Pr-doped LSCM-gadolinium-doped ceria (GDC)|scandia-stabilized zirconia|La0.6Sr0.4Co0.2Fe0.8O3-δ-GDC achieves an electrolysis current of 0.5 A cm−2 at 1.36 V and a Faradaic efficiency close to 100%. Short-term (210 h) stability testing of the cell under an electrolysis current of 0.5 A cm−2 at 800 °C with pure CO2 as the feedstock reveals a decrease in applied voltage at a rate of 7 mV kh−1, thereby indicating excellent stability. Thus, given its satisfactory performance and stability, the Pr-doped LSCM electrode may be considered a promising candidate material for direct CO2 electrolysis.  相似文献   

11.
Binder-free NiO/MnO2-carbon felt electrode is prepared with a facile two-step hydrothermal method. The NiO self-grown on the carbon felt is used as the skeleton structure to support the in-situ growth of MnO2. Both the core and shell materials are excellent pseudocapacitance materials. The compositing of such pseudocapacitance metal oxides can produce synergistic effects, so that the modified electrode has a high capacitance. NiO/MnO2-carbon felt electrode also possesses a high specific surface area, super hydrophilicity and good biocompatibility, which are conducive to the enrichment of typical exoelectrogen Geobacter. As the anode, NiO/MnO2-carbon felt electrode can effectively improve the electricity generation and methyl orange (MO) wastewater degradation performances of microbial fuel cell (MFC). The highest output voltage and the maximum power density of MFC with NiO/MnO2-carbon felt anode are respectively 652 mV and 628 mW m?2, which are much higher than those of MFC with MnO2-carbon felt anode (613 mV, 544 mW m?2), NiO-carbon felt anode (504 mV, 197 mW m?2) and unmodified carbon felt anode (423 mV, 162 mW m?2). The decolourization efficiency and the chemical oxygen demand (COD) removal rate of MO for MFC with NiO/MnO2-carbon felt anode are respectively 92.5% and 58.2% at 48 h.  相似文献   

12.
Microbial fuel cells (MFCs), a promising future energy conversion technology, play a significant role in the area of sustainable and renewable energy. In air-cathode MFCs, the catalytic activity for oxygen reduction reaction (ORR) of cathode electrocatalyst is the key factor to the performance of MFCs. Development of efficient and economical ORR electrocatalysts is an important step for the wide application of MFCs. Herein, Co wrapped carbon nanotubes (CNTs) N-doped nanoporous carbon materials (Co@NC-CoxZny) are constructed via a facile zinc-assisted growth pyrolytic approach of bimetallic zeolitic imidazole frameworks (BMZIFs)-derived strategy. They are directly prepared via carbonization of the precursor CoxZny-BMZIFs. During the pyrolysis process, the evaporation of zinc plays critical role in the in-situ growth of CNTs. For instance, the optimal catalyst, Co@NC-Co1Zn3, exhibits excellent ORR performance activity and stability with on-set potential (Eon-set) of 0.830 V (vs. RHE) and diffusion-limited current density (jL) of 6.706 mA cm?2, which is superior to the benchmark catalyst of commercial 20 wt% Pt/C. Additionally, Co@NC-Co1Zn3 displays four-electron pathway, long-term stability and better resistance to methanol tolerance. The MFC with Co@NC-Co1Zn3 cathode shows a maximum power density of 1039 mW m?2, and outperforms the MFC with commercial 20 wt% Pt/C catalyst (678 mW m?2). This work paved the way for exploring cost-effective, superior performance non-precious metal-based catalysts for air-cathode MFCs.  相似文献   

13.
Exploring advanced electrode materials with high electrochemical performance and sufficient durability is crucial to the commercialization of solid oxide fuel cells (SOFCs). Herein, a Ruddlesden-Popper Sr2·9La0·1Fe1·9Ni0·1O7?δ (SLFN) oxide is systematically evaluated as efficient oxygen electrode material. La and Ni co-doping strategy demonstrates improved oxygen desorption ability and promoted electrochemical activity of pristine Sr3Fe2O7?δ (SF) toward oxygen reduction react (ORR). Further, the ORR process of the SLFN electrode is probed by electrochemical impedance spectroscopy (EIS) and distribution of relaxation time (DRT) technique. The button cell with the SLFN cathode delivers a peak power density of 1.01 W cm?2 at 700 °C, along with desirable stability over a period of 60 h. This study offers a feasible strategy for developing Ruddlesden-Popper type cathode candidates for SOFCs.  相似文献   

14.
The present work is focused on the comparative analysis of electrochemical and structural properties of anode materials for solid oxide fuel cells (SOFCs) and the influence of factors affected on electrode performance. The Cu0.5Ce0.5O2−δ was prepared by Citrate–Nitrate route (CNP) and its formation is confirmed by XRD. The crystallite size of anode materials decreases with change of synthesis route. The highest conductivity is found to be 3.7 × 10−2 and 5.2 × 10−2 S cm−2 at 660 °C before and after reduction for CNP with suitable mechanical strength. The electrochemical performance of anode/electrolyte/anode interface of Cu0.5Ce0.5O2−δ is studied after reduction in presence of gas mixture (10%H2 + 90%N2) using electrochemical impedance spectroscopy. The conductivity for the Cell-800 prepared by CNP in presence of gas (10%H2 + 90%N2) shows lowest activation energy 1.28 eV. Thus, CNP is most promising method for obtaining the suitable anode material for the application of SOFC than Urea–Nitrate Process (UNP) and Glycine–Nitrate Process (GNP).  相似文献   

15.
Hierarchical hybrid heterostructures are regarded to be promising materials for highly efficient bifunctional electrocatalysts and high-performance supercapacitors due to their intriguing morphological features and remarkable electrochemical properties. Herein, we demonstrate the rational construct of cost-effective MoOx@NiS2 hybrid nanostructures as bifunctional electrocatalysts and the electrode material of supercapacitor. Microstructural analysis shows that the hybrid is a kind of hierarchical heterostructure composed of open and porous NiS2 nanowrinkles in situ grown on non-stoichiometric MoOx nanorods, which greatly improves the conductivity, and effectively maximized the electrochemical surface area. As expected, the MoOx@NiS2 hybrid show remarkable electrocatalytic performance in alkaline media, such as overpotentials of 101 mV at 10 mA cm?2 for hydrogen evolution reaction (HER) and 278 mV at 20 mA cm?2 for oxygen evolution reaction (OER), and a low cell voltage of 1.62 V to deliver a current density of 10 mA cm?2. Moreover, the hybrid nanostructures present a high specific capacitance 1050 A/g at 1 A/g with ultra-long stability in 6 M KOH. The strategy proposed here introduces a new perspective about the development of efficient earth-abundant bifunctional elecrocatalysts and electrode materials for superior energy conversion and storage devices.  相似文献   

16.
Solid oxide fuel cell (SOFC) has experienced a growing interest in the last few decades because of generating energy more efficiently than the conventional combustion of fossil fuels. By using the same material as anode and cathode of SOFC (symmetric fuel cell), the production of reliable and repeatable cells would be simpler. In this work, La0.4Sr0.6Co0.2Fe0.7Nb0.1O3−δ (LSCFN) perovskite has been prepared and evaluated as both cathode and anode material of symmetric fuel cell. The results of symmetric fuel cell show that a maximum peak power density of 500 mW cm−2 has been achieved and the total electrode polarization resistances of the cell is only 0.22 Ω cm2 at 850 °C which is much lower than that of typical symmetric fuel cell with La0.75Sr0.25Cr0.5Mn0.5O3−δ as electrode material. All of these results indicate that LSCFN can potentially be a promising candidate for the electrode material of symmetric fuel cell.  相似文献   

17.
In the present work, nitrogen doped hierarchically activated porous carbon (APC) samples have been synthesized via single step scalable method using ethylene di-amine tetra acetic acid (EDTA) as precursor and KOH as activating agent. Activated porous carbons with different pore sizes have been developed by varying the activation temperature. SEM, TEM and SAXS analysis suggest that with variation of activation temperature, a hierarchical porous structure with interconnected meso-pore and micro pores has been achieved. The sufficiently high surface area of the synthesized materials provides active sites to enhance the diffusion of ions between the electrolyte and the carbon electrodes. The electrode prepared at 800 °C activated sample exhibited highest specific capacitance of 274 Fg-1 in two electrode setup, at a current density of 0.1 Ag-1 in 1 M aqueous H2SO4. Along with this, it showed maximum energy density of 9.5 Whkg?1 at a power density of 64.5 Wkg-1. The remarkable electrochemical performance reveals that the synthesized nitrogen doped activated carbon electrodes derived from EDTA can be tuned to have optimum pore structure and pore size distribution for better electrochemical performance, so it can be considered as a potential electrode material for applications in electrochemical energy storage.  相似文献   

18.
We present combined Synchrotron X-ray Absorption Near Edge Spectroscopy (XANES) and Extended X-ray Absorption Fine Structure (EXAFS) study of La0.4Sr0.6Ti1−yCoyOδ (0 ≤ y ≤ 0.5), which are promising electrode materials for symmetric solid oxide fuel cells. The measurements were performed at room temperature at the Ti and the Co K-edges in order to determine the local structural and electronic changes around the two transition metals. We find that Ti remains in a higher formal valence (around 4+) independent of the Co concentration. In contrast to this, dramatic and systematic changes are observed for the Co as a function of y. We conclude that the stability of the Ti4+ triggers the A-site deficiency in our samples and predicts that oxygen vacancies are much more easily formed at large Co content, which in turn will greatly enhance the performance as electrode material.  相似文献   

19.
In this study, the hetero-structure of MgCo2O4 nanowires (MCO-NWs) and microcubes (MCO-MCs) on the skeleton of nickel foam (NF) was realized through a simple hydrothermal method and subsequent annealing treatment, and then served as a binder-free cathode for assembly of high-performance hybrid supercapacitor (HSC). Such synthetic methodology avoided the traditional usage of conductive and binder reagents for the electrode fabrication. The electrochemical tests indicated its battery-type characteristics, and the MCO-NWs@NF exhibited a huge specific capacity (Cs) of 389.0 C g?1 as well as 86.2% capacity retention when the current density boosted from 1 to 10 A g?1. The assembled HSC with activated carbon (AC) as anode further demonstrated the advantages of this electrode material. After 5000 cycles at 6 A g?1, the MCO-NWs@NF//AC HSC showed good long-term cycling stability without any decay in capacitance, and could deliver an energy density (Ed) of 37.9 W h kg?1 at the power density (Pd) of 958.1 W kg?1, higher than the 30.4 W h kg?1 of MCs-based HSC. These impressive results regarding electrochemical performance suggest that MCO-NWs@NF may be a promising candidate to serve as a battery-type material in electrochemical energy storage applications such as HSCs, batteries, and so on.  相似文献   

20.
Microfluidic fuel cell (MFC) suffers from small single cell output power due to the inherent cell size limitation as microscale geometries are prerequisite to prevent reactant crossover between the anode and cathode. To meet the power demand of practical applications, previous works mainly focus on the creating of MFC stacks with multiple cells connected in series, parallel, or mixture of both series and parallel to increase the output power. Yet, low energy efficiency is observed because of the flow distribution nonuniformity and shunt current losses. In this work, a high performance radial vanadium redox MFC is presented to address the size limitation issue by adding a separate layer between the porous electrodes of the conventional plate‐frame MFC. Specific cell characteristics are detailed by mathematical modeling, and parametric studies are performed to evaluate the influences of the geometrical and operational parameters on the cell performance. The results show that this new radial MFC can provide a higher fuel utilization and meanwhile an improved cell performance under a fixed electrode size compared with the conventional plate‐frame MFC. Moreover, the electrode size limitation due to the reactant crossover between the anode and cathode is broken as the influences of the electrode size on the mixing region are greatly reduced. In the case with the electrode size equal to 18 mm × 18 mm , single cell output power of 0.35 mW with a fuel utilization of 53.33% is obtained under the reactant concentration of 2 mol L?1 and flow rate of 300 μL min?1 .  相似文献   

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