scholarly journals Carbon-Encapsulated Iron Nanoparticles as a Magnetic Modifier of Bioanode and Biocathode in a Biofuel Cell and Biobattery

Catalysts ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 705
Author(s):  
Roman Chomicz ◽  
Michał Bystrzejewski ◽  
Krzysztof Stolarczyk

This work demonstrates the application of magnetic carbon-encapsulated iron nanoparticles (CEINs) for the construction of bioelectrodes in a biobattery and a biofuel cell. It has been shown that carbon-encapsulated iron nanoparticles are a suitable material for the immobilization of laccase (Lc) and 1,4-naphthoquinone (NQ) and fructose dehydrogenase (FDH). The system is stable; no leaching of the enzyme and mediator from the surface of the modified electrode was observed. The onset of the catalytic reduction of oxygen to water was at 0.55 V, and catalytic fructose oxidation started at −0.15 V. A biobattery was developed in which a zinc plate served as the anode, and the cathode was a glassy carbon electrode modified with carbon-encapsulated iron nanoparticles, laccase in the Nafion (Nf) layer. The maximum power of the cell was ca. 7 mW/cm2 at 0.71 V and under external resistance of 1 kΩ. The open-circuit voltage (OCV) for this system was 1.51 V. In the biofuel cell, magnetic nanoparticles were used both on the bioanode and biocathode to immobilize the enzymes. The glassy carbon bioanode was coated with carbon-encapsulated iron nanoparticles, 1,4-naphthoquinone, fructose dehydrogenase, and Nafion. The cathode was modified with carbon-encapsulated magnetic nanoparticles and laccase in the Nafion layer. The biofuel cell parameters were as follows: maximum power of 78 µW/cm2 at the voltage of 0.33 V and under 20 kΩ resistance, and the open-circuit voltage was 0.49 V. These enzymes worked effectively in the biofuel cell, and laccase also effectively worked in the biobattery.

Author(s):  
Budiyanto Budiyanto ◽  
Fadliondi Fadliondi

This paper explains the experimental investigation to improve the output power of solar cell using cooling and light reflection from mirrors. The results show that by adding mirror, the current and output power of solar cell increase but the open circuit voltage and maximum power voltage decrease due to heat. By adding cooling, the open circuit voltage and the maximum power voltage are improved, so the output power also increases.


Electronics ◽  
2019 ◽  
Vol 8 (3) ◽  
pp. 321 ◽  
Author(s):  
Dmitry Baimel ◽  
Saad Tapuchi ◽  
Yoash Levron ◽  
Juri Belikov

This paper proposes two new Maximum Power Point Tracking (MPPT) methods which improve the conventional Fractional Open Circuit Voltage (FOCV) method. The main novelty is a switched semi-pilot cell that is used for measuring the open-circuit voltage. In the first method this voltage is measured on the semi-pilot cell located at the edge of PV panel. During the measurement the semi-pilot cell is disconnected from the panel by a pair of transistors, and bypassed by a diode. In the second Semi-Pilot Panel method the open circuit voltage is measured on a pilot panel in a large PV system. The proposed methods are validated using simulations and experiments. It is shown that both methods can accurately estimate the maximum power point voltage, and hence improve the system efficiency.


2003 ◽  
Vol 763 ◽  
Author(s):  
D. Guimard ◽  
N. Bodereau ◽  
J. Kurdi ◽  
J.F. Guillemoles ◽  
D. Lincot ◽  
...  

AbstractCuInSe2 and Cu(In, Ga)Se2 precursor layers have been prepared by electrodeposition, with morphologies suitable for device completion. These precursor films were transformed into photovoltaic quality films after thermal annealing without any post-additional vacuum deposition process. Depending on the preparation parameters annealed films with different band gaps between 1eV and 1.5 eV have been prepared. The dependence of resulting solar cell parameters has been investigated. The best efficiency achieved is about 10,2 % for a band gap of 1.45 eV. This device presents an open circuit voltage value of 740 mV, in agreement with the higher band gap value. Device characterisations (current-voltage, capacitance-voltage and spectral response analysis) have been performed. Admittance spectroscopy at room temperature indicates the presence of two acceptor traps at 0.3 and 0.43 eV from the valance band with density of the order of 2. 1017 cm-3 eV-1.


2019 ◽  
Vol 8 (4) ◽  
pp. 402
Author(s):  
Doudou N. Luta ◽  
Atanda K. Raji

The concept of power tracking was at first applied to renewable power systems and especially those based on solar and wind to extract as much power as possible from them. Both types of power systems operate on the principle of converting either solar or wind into electricity. Thus, their output power is direct dependent on the solar radiation for solar power systems and on the wind speed for wind generators. To maintain efficient system operations, the output power of these power systems is optimized through maximum power tracking techniques. In the similar vein, fuel cell stacks display nonlinear output powers resulting from internal limitations and operating parameters such as tem-perature, hydrogen and oxygen partial pressures and humidity levels, etc., leading to a reduced system performance. It is critical to extract as much power as possible from the stack, thus, to prevent also an excessive fuel use. To ensure that, the power converter interfaced to the stack must be able to self-adjust its parameters continuously, hence modifying its voltage and current depending upon the maximum power point position. Diverse techniques are utilized to extract maximum power from the fuel-cell stack.  In this paper, a fractional open circuit voltage and fuzzy rule based maximum power tracking techniques are considered and compared. The proposed system consists of a 50 kW Proton Exchange Membrane fuel cell interfaced to a DC-to-DC boost converter. The converter is designed to deliver 1.2 kV from 625 V input voltage. The simulation is carried out under Matlab/Simulink environment.  


Author(s):  
Ibukun Akinsola ◽  
Aderemi Babatunde Alabi ◽  
Muibat A Soliu ◽  
Taiye Akomolafe

Enzymatic fuel cells produce electrical power by oxidation of renewable energy sources. An enzymatic glucose biofuel cell uses glucose as fuel and enzymes as biocatalyst, to convert biochemical energy into electrical energy. The applications which need low electrical voltages and low currents have much of the interest in developing enzymatic fuel cells. The cell was constructed using three different materials with different electrodes (Bitter leaf and Copper electrodes (BCu), Bitter leaf and Carbon electrodes (BC) and Water leaf and Carbon electrodes (WC)). The short circuit current and open circuit voltage were measured in micro-ampere (mu A) and milli-volt (mV) respectively at 30 minutes interval over the period of 12 hours (from dawn to dusk). The results which show that fuel cells constructed using bitter leaf with carbon electrode has the highest open circuit voltage, short circuit current and generated power of 162.8~mV, 1.65~ mu A and 268.62~nW respectively at 720~mins is obtained from the plots generated by the use of Microsoft Excel. The results show that all short circuit currents, voltages and powers generated increases with time and this is as a result of the exposure to solar radiation during the period of taking the measurement.


Author(s):  
Ferdaws Ben Naceur ◽  
◽  
Abdelaziz Salah Saidi ◽  
Javed Khan Bhutto ◽  
Mohamed Ali Mahjoub ◽  
...  

This paper deals with the problem of the optimization of the power, delivered by the photovoltaic panel (PVP). To achieve this aim, a neuro-fuzzy estimator (NFE), followed by a conversion coefficient and a calculation stage of the optimal duty cycle, has been developed. The NFE is used to calculate the open circuit voltage corresponding to each solar radiation, based only on the standard open circuit voltage. A coefficient, determining for each climatic condition the voltage of the maximum power directly from the open circuit voltage, is estimated by a measured test. Finally, the optimal duty cycles, next, determined by the input/output equation of boost converter. The system performance, under different scenarios, has been checked carrying out MATLAB simulations, using an existing photovoltaic model and real weather data, and comparing the simulation results with the measured one. The results demonstrate the effectiveness of the present approach. The efficiency of the proposal maximum power point tracking (MPPT) is proved and it showed that this controller can generate almost 99% of the real PVP maximum power.


Sign in / Sign up

Export Citation Format

Share Document