scholarly journals Perspective on advanced nanomaterials used for energy storage and conversion

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Hsuanyi Huang ◽  
Rong Li ◽  
Cuixia Li ◽  
Feng Zheng ◽  
Giovanni A. Ramirez ◽  
...  

Abstract To drive the next ‘technical revolution’ towards commercialization, we must develop sustainable energy materials, procedures, and technologies. The demand for electrical energy is unlikely to diminish over the next 50 years, and how different countries engage in these challenges will shape future discourse. This perspective summarizes the technical aspects of nanomaterials’ design, evaluation, and uses. The applications include solid oxide fuel cells (SOFCs), solid oxide electrolysis cells (SOEC), microbial fuel cells (MFC), supercapacitors, and hydrogen evolution catalysts. This paper also described energy carriers such as ammonia which can be produced electrochemically using SOEC under ambient pressure and high temperature. The rise of electric vehicles has necessitated some form of onboard storage of fuel or charge. The fuels can be generated using an electrolyzer to convert water to hydrogen or nitrogen and steam to ammonia. The charge can be stored using a symmetrical supercapacitor composed of tertiary metal oxides with self-regulating properties to provide high energy and power density. A novel metal boride system was constructed to absorb microwave radiation under harsh conditions to enhance communication systems. These resources can lower the demand for petroleum carbon in portable power devices or replace higher fossil carbon in stationary power units. To improve the energy conversion and storage efficiency, we systematically optimized synthesis variables of nanomaterials using artificial neural network approaches. The structural characterization and electrochemical performance of the energy materials and devices provide guidelines to control new structures and related properties. Systemic study on energy materials and technology provides a feasible transition from traditional to sustainable energy platforms. This perspective mainly covers the area of green chemistry, evaluation, and applications of nanomaterials generated in our laboratory with brief literature comparison where appropriate. The conceptual and experimental innovations outlined in this perspective are neither complete nor authoritative but a snapshot of selecting technologies that can generate green power using nanomaterials.

2021 ◽  
Author(s):  
Maoyu Wang ◽  
Zhenxing Feng

Electrochemical energy systems such as batteries, water electrolyzers, and fuel cells are considered as the promising and sustainable energy storage and conversion devices due to their high energy densities and...


Author(s):  
Diogo Ortiz Machado ◽  
Diana Francisca Adamatti ◽  
Eder Mateus Nunes Gonçalves

Microbial Fuel Cells (MFC) could generate electrical energy combined with the wastewater treatment and they can be a promising technological opportunity. This chapter presents an agent-based model and simulation of MFC comparing it with analytical models, to show that this approach could model and simulate these problems with more abstraction and with excellent results.


2012 ◽  
Vol 727-728 ◽  
pp. 769-774
Author(s):  
A. Ávila ◽  
J. Poveda ◽  
D. Gómez ◽  
D. Hotza ◽  
J. Escobar

Solid oxide fuel cells (SOFCs) have emerged as an efficient way to transform chemical energy into electrical energy. However, a major disadvantage of this technology is related to the high temperatures required for SOFC operation. In this way, new materials are necessary to maintain the electrical properties of the cell at intermediate temperatures. Based on these ideas, it is necessary to study both the structural variation of the cells components at different temperatures and their electrochemical behavior. In this work, a crystallographic characterization is presented, which was performed in a commercial SOFC cell using X-ray diffraction (XRD). An equivalent linear electrical model to predict SOFC losses is developed as well. Keywords: Solid oxide fuel cells (SOFCs); AC impedance; Electrochemical impedance spectroscopy (EIS); Equivalent circuit models.


Author(s):  
Juhyun Kang ◽  
Joonguen Park ◽  
Joongmyeon Bae

Hydrogen is a resource that provides energy and forms water only after reacting with oxygen. Because there are no emissions such as greenhouse gases when hydrogen is converted to produce energy, it is considered one of the most important energy resources for addressing the problems of global warming and air pollution. Additionally, hydrogen can be useful for constructing “smart grid” infrastructure because electrical energy from other renewable energy sources can be stored in the form of chemical energy by electrolyzing water, creating hydrogen. Among the many hydrogen generation systems, solid oxide electrolysis cells (SOECs) have attracted considerable attention as advanced water electrolysis systems because of their high energy conversion efficiency and low use of electrical energy. To find the relationship between operating conditions and the performance of SOECs, research has been conducted both experimentally, using actual SOEC cells, and numerically, using computational fluid dynamics (CFD). In this investigation, we developed a 3-D simulation model to analyze the relationship between the operating conditions and the overall behavior of SOECs due to different contributions to the over-potential. All SOECs involve the transfer of mass, momentum, species, and energy, and these properties are correlated. Furthermore, all of these properties have a direct influence on the concentration of the gases in the electrodes, the pressure, the temperature and the current density. Therefore, the conservation equations for mass, momentum, species, and energy should be included in the simulation model to calculate all terms in the transfer of mass, heat and fluid. In this simulation model, the transient term was neglected because the steady state was assumed. All governing equations were calculated using Star-CD (CD Adapco, U.S). The source terms in the governing equations were calculated with in-house code, i.e., user defined functions (UDF), written in FORTRAN 77, and these were linked to the Star-CD solver to calculate the transfer processes. Simulations were performed with various cathode inlet gas compositions, anode inlet gas compositions, cathode thickness, and electrode porosity to identify the main parameters related to performance.


2006 ◽  
Vol 3 (4) ◽  
pp. 499-502 ◽  
Author(s):  
N. J. J. Dekker ◽  
G. Rietveld

Hydrogen is the fuel for fuel cells with the highest cell voltage. A drawback for the use of hydrogen is the low energy density storage capacity, even at high pressures. Liquid fuels such as gasoline and methanol have a high energy density but lead to the emission of the greenhouse gas CO2. Ammonia could be the ideal bridge fuel, having a high energy density at relative low pressure and no (local) CO2 emission. Ammonia as a fuel for the solid oxide fuel cell (SOFC) appears to be very attractive, as shown by cell tests with electrolyte supported cells (ESC) as well as anode supported cells (ASC) with an active area of 81cm2. The cell voltage was measured as function of the electrical current, temperature, gas composition and ammonia (NH3) flow. With NH3 as fuel, electrical cell efficiencies up to 70% (LHV) can be achieved at 0.35A∕cm2 and 60% (LHV) at 0.6A∕cm2. The cell degradation during 3000 h of operation was comparable with H2 fueled measurements. Due to the high temperature and the catalytic active Ni∕YSZ anode, NH3 cracks at the anode into H2 and N2 with a conversion of >99.996%. The high NH3 conversion is partly due to the withdrawal of H2 by the electrochemical cell reaction. The remaining NH3 will be converted in the afterburner of the system. The NOx outlet concentration of the fuel cell is low, typically <0.5ppm at temperatures below 950°C and around 4ppm at 1000°C. A SOFC system fueled with ammonia is relative simple compared with a carbon containing fuel, since no humidification of the fuel is necessary. Moreover, the endothermic ammonia cracking reaction consumes part of the heat produced by the fuel cell, by which less cathode cooling air is required compared with H2 fueled systems. Therefore, the system for a NH3 fueled SOFC will have relatively low parasitic power losses and relative small heat exchangers for preheating the cathode air flow.


2000 ◽  
Vol 66 (4) ◽  
pp. 1292-1297 ◽  
Author(s):  
Doo Hyun Park ◽  
J. Gregory Zeikus

ABSTRACT Neutral red (NR) was utilized as an electron mediator in microbial fuel cells consuming glucose to study both its efficiency during electricity generation and its role in altering anaerobic growth and metabolism of Escherichia coli andActinobacillus succinogenes. A study of chemical fuel cells in which NADH, NR, and ferricyanide were the electron donor, the electronophore, and the electron acceptor, respectively, showed that electrical current produced from NADH was proportional to the concentration of NADH. Fourfold more current was produced from NADH in chemical fuel cells when NR was the electron mediator than when thionin was the electron mediator. In microbial fuel cells in which E. coli resting cells were used the amount of current produced from glucose when NR was the electron mediator (3.5 mA) was 10-fold more than the amount produced when thionin was the electron mediator (0.4 mA). The amount of electrical energy generated (expressed in joules per mole of substrate) and the amount of current produced from glucose (expressed in milliamperes) in NR-mediated microbial fuel cells containing either E. coli or A. succinogeneswere about 10- and 2-fold greater, respectively, when resting cells were used than when growing cells were used. Cell growth was inhibited substantially when these microbial fuel cells were making current, and more oxidized end products were formed under these conditions. When sewage sludge (i.e., a mixed culture of anaerobic bacteria) was used in the fuel cell, stable (for 120 h) and equivalent levels of current were obtained with glucose, as observed in the pure-culture experiments. These results suggest that NR is better than other electron mediators used in microbial fuel cells and that sludge production can be decreased while electricity is produced in fuel cells. Our results are discussed in relation to factors that may improve the relatively low electrical efficiencies (1.2 kJ/mol) obtained with microbial fuel cells.


2014 ◽  
Vol 976 ◽  
pp. 70-74
Author(s):  
Iván L. Samperio-Gómez ◽  
Claudia A. Cortés-Escobedo ◽  
A.M. Bolarín-Miró ◽  
Félix Sánchez de Jesús

Several methods for processing tubular anodes for solid oxide fuel cells have been developed, but many of them are expensive and sophisticated, therefore, there is a great interest in researching the use of a simple process to produce them. In this paper, the results of using slip casting for processing minitubes of NiO-8YSZ with the dimensions of 100x5x1 mm are presented. This is a versatile method for obtaining complex geometries with a suitable surface finish and dimensional precision at low cost compared with ceramic processing which uses high energy consumption and/or has high startup costs. In order to carry out this study, an aqueous slurry of an oxide mixture of NiO-8YSZ with poly-etilenglycol as a dispersant agent was used. The modification of the ratio of water:ceramic powders, the composition NiO:x8YSZ (30, 50 and 70 in wt.) and the casting time (3 to 30 min) were also applied. The minitubes obtained were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and spectroscopy of dispersive energy (EDS). The results show that slip casting is an appropriate method to obtain NiO-8YSZ minitubes. Minitubes of varying composition (30, 50 and 70% in wt. of NiO) with dimensions of 100x5x1 mm were obtained showing an excellent porosity (higher than 96% in v/v) and a homogeneous distribution of NiO and 8YSZ particles. XRD analysis confirms the presence of starting oxides before and after the casting process.


2020 ◽  
Vol 12 (2) ◽  
pp. 1-9
Author(s):  
Vidia Wahyu Meidy Safitri ◽  
Tuhu Agung Rachmanto

ABSTRAK Limbah cair tahu mengandung kandungan organik tinggi dengan konsentrasi COD 1408 mg/l, TSS 191 mg/l dan pH 4,46.  Salah satu penelitian dengan pemanfaatan limbah dan energi yaitu Microbial Fuel cell (MFC). Energi Kimia senyawa organik dari mikroorganisme akan dirubah menjadi energi listrik dengan reaksi katalik dari mikroorganisme dalam keadaan anaerob merupakan proses microbial fuel cells. Salah satu tantangan untuk mengembangkan sistem MFC adalah dengan memilih elektroda yang tepat. Elektroda yang digunakan harus memiliki daya konduktifitas listrik tinggi, pemukaan yang luas, non korosif, biokompatibel, stabil. Penelitian ini bertujuan untuk memgetahui jenis elektroda optimum dalam menghasilkan power density dengan variasi elektroda karbon grafit, seng dan tembaga, variasi waktu 0, 48, 96, 144, dan 192 jam. Dilakukan pre-treatment koagulasi flokulasi. Hasil penelitian menunjukkan bahwa MFC dengan elektroda karbon grafit dan karbon grafit menghaslikan power density sebesar 2292,994 mW/m2. MFC juga menurunkan konsentrasi COD hingga 88%. Waktu pengolahan dapat mempengaruhi efisiensi penyisihan COD.   Kata kunci: limbah tahu, microbial fuel cell, power density   ABSTRACT   Tofu liquid waste contains high organic content with a COD concentration of 1408 mg / l, TSS 191 mg / l and pH 4.46. One of the researches related to waste and energy utilization is Microbial Fuel cell (MFC). Chemical energy organic compounds from microorganism will be converted into electrical energy by the catalytic reaction of microorganism in anaerobic conditions is a process of microbial fuel cells. One of the challenges to developing an MFC system is to choose the right electrodes. The electrodes used must have high electrical conductivity, a wide surface, non-corrosive, biocompatible, stable. This study aims to find out the most optimum type of electrode in producing power density with variations of carbon graphite, zinc and copper, variations of 0, 48, 96, 144, and 192 hours. The pre-treatment are Coagulation-flocculation. The results showed that MFC with carbon graphite and carbon graphite electrodes produced a power density of 2292,994 mW/m2. MFC also reduces COD concentrations up to 88%. Processing time can affect the efficiency of COD removal.   Keywords: Tofu Liquid Waste, Microbial Fuel Cells, power density


Sign in / Sign up

Export Citation Format

Share Document