Small Laboratory Cells Research Articles

Slot‐Die Deposition of CuSCN Using Asymmetric Alkyl Sulfides as Cosolvent for Low‐Cost and Fully Scalable Perovskite Solar Cell Fabrication

The development of industrially relevant deposition processes for efficient, stable, and inexpensive charge extracting layers is crucial for the commercialization of perovskite solar cells (PSCs). This work demonstrates, for the first time, the deposition of copper thiocyanate (CuSCN) as a low‐cost and reliable hole‐transport layer using slot‐die coating. Methyl ethyl sulfide is thereby used as an asymmetric cosolvent to significantly increase the solubility of CuSCN in the utilized slot‐die ink compared to traditional pure diethyl sulfide‐based solutions. Optimized CuSCN inks allow for the deposition of CuSCN layers on 5 × 10 cm2 substrates with a wide range of thicknesses. Multidimensional imaging photoluminescence techniques are used to investigate the uniformity of the CuSCN thin films deposition as well as the influence of the solvent on charge losses. Finally, the CuSCN slot‐die deposition is integrated into a fully upscalable PSC fabrication process showing 19.1% power conversion efficiency for small laboratory cells and 14.7% for 9 cm2 minimodules. Furthermore, semitransparent minimodules retain 80% of their initial efficiency after 500 h of constant illumination.

Phosphorous extraction and heavy metal separation from sewage sludge ash by two-compartment electrodialysis in an upscaled tube reactor

Two-compartment electrodialytic extraction (2C-ED) is a one-step process for the simultaneous phosphorous extraction and separation of heavy metals from sewage sludge ash (SSA). The process is driven by an applied electric DC field, which can be supplied from renewable sources. The proof-of-concept of the method was conducted in small laboratory cells; however, upscaling to a continuous 2C-ED process, which additionally can treat SSA suspensions at a low liquid-to-solid (L:S) ratio, requires a new design. This paper presents such a new design. In principle, ED consists of two compartments separated by a cation exchange membrane. One compartment contains a suspension of SSA in water and the anode. A cathode is placed in the other compartment. Electrolysis at the anode acidifies the suspension causing the dissolution of phosphorous and heavy metals. The heavy metals are separated from the suspension by electromigration into the catholyte, whereas the dissolved phosphorous remains in the dispersion solution. In the new design, the SSA was suspended in a tube-shaped reactor with the cation exchange membrane covering the outside. The reactor was placed in a container with the catholyte. Periodically turning off the reactor kept SSA in suspension even at a low L:S ratio without corners and pockets where the SSA otherwise tends to settle. Five 2C-ED experiments were conducted with 1.5 to 3 kg SSA at varying currents and durations. Up to 89% P was extracted. The extracted P was concentrated in the dispersion solution of the SSA suspension, where the obtained P-related concentrations of heavy metals were far below the limiting values for spreading on agricultural land. The experiments underlined that treating the SSA in a suspension with a low L:S ratio is advantageous. A comparison to previous laboratory experiments in small cells treating 50 g SSA shows a significantly more efficient use of the applied current in the new reactor setup. Thus, the new reactor design for 2C-ED fulfilled the set criteria for the operation and did additionally result in a higher efficiency than the laboratory setups, i.e., the design can be the first step towards an upscaling.

(Invited) Iron Flow Battery with Slurry Electrode for Large Scale Energy Storage: Scale-up, Commercialization, and IP Challenges in an Academic Environment

Large-scale energy storage is required to meet a multitude of current energy challenges. These challenges include modernizing the grid, incorporating intermittent renewable energy sources (so as to dispatch continuous electrical energy), improving the efficiency of electricity transmission and distribution, and providing flexibility of storage independent of geographical and geological location.Through efforts supported by ARPA-E and the Department of Energy Office of Electricity, one technology we are developing utilizes an approach based on sustainable, low cost iron electrolytes in an iron flow battery (IFB). Advantages of the IFB include abundant, non-toxic, and non-corrosive materials that are used to provide an energy storage solution that has inherently safe operation and is environmentally friendly. In our approach to the all iron RFB, we introduced a flowing carbon slurry as the negative electrode as a substrate for plating iron during charging allowing storage of the plated iron in a tank external to the stack. This configuration decouples energy and power capacities. The work supported by DOE allowed us to address challenges encountered in scaling up from small laboratory cells to a large commercial size slurry IFB single cell. 1 In this presentation, we will address some of the challenges we encountered for demonstrating the technology within an academic environment in order to position it for commercial development. Even with funding to overcome the valley-of-death and technology-to-market assistance given by ARPA-E, we faced many challenges including hiring expertise to address scale-up, design and testing. We will discuss challenges faced with identifying partners and licensees for moving discovery to product. Also, we will describe the many types of interactions we had with the university Technology Transfer Office including patent disclosure, IP protection, and negotiating licenses. Acknowledgements: This research was supported by ARPA-E contract DE-AR0000352. Partial support also was received from the DOE Office of Electricity Award #1111358,0 under Dr. Imre Gyuk. 1N.S. Sinclair, R.F. Savinell and J.S. Wainright, MRS Energy & Sustainability, 2022; doi: 10.1557/s43581-022-00046-8

Implications of the Heat Generation of LMR-NCM on the Thermal Behavior of Large-Format Lithium-Ion Batteries

Lithium- and manganese-rich NCM (LMR-NCM) cathode active materials exhibit a pronounced energy inefficiency during charge and discharge that results in a strong heat generation during operation. The implications of such a heat generation are investigated for large-format lithium-ion batteries. Small laboratory cells are generally considered isothermal, but for larger cell formats this heat cannot be neglected. Therefore, the heat generation of LMR-NCM/graphite coin cells and NCA/graphite coin cells as a reference is measured for varying charge/discharge rates in an isothermal heat flow calorimeter and scaled to larger standardized cell formats. With the aid of thermal 3D models, the temperature evolution within these cell formats under different charge/discharge operations and cooling conditions is analyzed. Without an additional heat sink and any active cooling of larger LMR-NCM/graphite cells, discharge C-rates lower than C/2 are advisable to keep the cell temperature below a critical threshold. If the loads are increased, the cooling strategy has to be adapted to the specific cell format, otherwise critical temperatures above 60 °C are easily reached. For the investigated convective surface cooling and base plate cooling scenarios, thick prismatic cell formats with LMR-NCM are generally unfavorable, as the large amount of heat cannot be adequately dissipated.

Development and evaluation of a composite supercapacitor-based 12 V transient start–stop power system for vehicles: Modelling, design and fabrication scaling up

The study involves a bottom-up approach, from bottom cells to large supercapacitor pouch cells, encompassing the design, modelling and fabrication stages of the cells leading to a 12 V transient start–stop (TSS) power system for automotive applications. More specifically, the design of a large composite supercapacitor is presented, consisting of a high power density component and a high energy density component, hybridised at material level. The composition of the composite supercapacitor is optimised to be application-specific so that it satisfies a specified energy-to-maximum power ratio for the 12 V TSS system. The testing of the large composite supercapacitor pouch cells and the 12 V TSS system proves the validity of the bottom-up approach, validates the design and the proposed electric circuit model and its parameters, fitted according to experimental data of small laboratory cells and applied successfully to the large cells, and proves the high quality of the scaled-up fabrication processes. The 12 V TSS power system of seven large composite supercapacitor cells satisfies the set criteria of energy and maximum power for the specified duration, 15 Wh and 4.2 kW respectively, at a total mass of 3.94 kg, below the original set limit of 5 kg.

Study on a high current density redox flow battery with tin(Ⅱ)/tin as negative couple

The cyclic voltammetry characteristics of Sn2+/Sn couple in the H2SO4 medium on a graphite felt electrode is evaluated. The charge–discharge performance of Sn–V battery with VO2+/VO2+ couple as positive part and Sn2+/Sn couple as negative part is investigated through a small laboratory cell. The result shows that though the deposition/dissolution of Sn is not a normal reversible process, Sn deposits can almost dissolve completely during the charge–discharge tests. It is remarkable that the battery could work normally at a current density of 180 mA cm−2 with an average voltage efficiency of 72%.

State-of-Charge Monitoring and Electrolyte Rebalancing Methods for the Vanadium Redox Flow Battery

A major issue with all flow batteries is the control of the imbalance between the two half-cell electrolytes that arises as a result of the differential transfer of ions across the membrane and the inevitable gassing side reactions that can occur during charging. While a number of methods are available to rebalance electrolyte state of charge and restore capacity, reliable methods are needed to monitor the state-of-charge of each individual half-cell solution in order to determine the appropriate action to be taken by the battery control system. In this study different methods of state-of-charge monitoring have been considered for application in the All-Vanadium Redox Flow Battery (VRB). Half-cell potentials and electrolyte conductivities were calibrated as a function of state-of-charge and evaluated for state-of-charge monitoring of individual half-cell electrolytes for the purpose of capacity restoration and control. An empirical model based on experimental conductivity data has been shown to provide accurate predictions, with an average error of 0.77%, of the conductivity of the positive half-cell electrolyte as a potential state-of-charge detection tool. Separate monitoring of the two half-cell electrolyte potentials has also been used to determine the state-of-charge of each half-cell solution in order to detect system imbalance. This was used in small laboratory cell tests to determine necessary actions to restore capacity by either remixing the two solutions, or by using chemical rebalancing methods, depending on the cause of the solution imbalance.

The effect of electrolyte filling method on the performance of dye-sensitized solar cells

The effect of electrolyte filling method on the performance of the dye-sensitized solar cells is investigated with the segmented cell method, a recent technique which is very simple but effective as it can be used to examine all the photovoltaic characteristics. The electrolyte filling techniques compared were single injection, which is typically used in small laboratory cells, and pumping the electrolyte through the cell several times, which is often used for larger cells and modules. Significant photovoltage and photocurrent variations occur with the repeated pumping of the electrolyte in the cell preparation. Transient and charge extraction measurements confirmed that the differences in open circuit voltage were due to the shifts of the TiO2 conduction band and time correlated single photon counting confirmed that the reduction of short circuit current was largely due to reduced electron injection correlated with the increasing conduction band edge in the studied cases. This was interpreted as an effect of molecular filtering by the TiO2 causing an accumulation of electrolyte additives (4-tert-butylpyridine and benzimidazole) near the electrolyte filling hole, the concentration of which increased with repeated pumping of the electrolyte. Interestingly, spatial variations were seen not only in the relative TiO2 conduction band energy but also in the density of trap states. In this contribution it is demonstrated how the changes in the conduction band can be separated from the changes in the density of trap states which is an essential for the correct interpretation of the data.

Study on a single flow acid Cd–chloranil battery

This paper describes a novel redox flow battery–single flow acid Cd–chloranil battery. The electrolyte of this battery for both negative electrode and positive electrode is the aqueous intermixture of H 2SO 4–(NH 4) 2SO 4–CdSO 4, the negative electrode is inert metal such as copper foil, and the positive electrode is an insoluble organic material, tetrachloro- p-benzoquinone (chloranil). Typically, the electrolyte is continuously circulated to pass though the cells by means of a single pump as the battery is on duty. There is no requirement for a membrane. Tetrachloro- p-benzo-hydroquinone is oxidized to chloranil at positive electrode and the cadmium ions is reduced to cadmium and electroplated onto the negative electrode during charge. The reverse occurs during discharge. Results obtained with a small laboratory cell show that high efficiencies can be achieved with an average coulombic efficiency of 99% and energy efficiency of 82% over 100 cycles at the current density of 10 mA cm −2.

The Zn(S,O,OH)/ZnMgO buffer in thin‐film Cu(In,Ga)(Se,S)2‐based solar cells part II: Magnetron sputtering of the ZnMgO buffer layer for in‐line co‐evaporated Cu(In,Ga)Se2 solar cells

AbstractA ZnS/Zn1‐xMgxO buffer combination was developed to replace the CdS/i‐ZnO layers in in‐line co‐evaporated Cu(In,Ga)Se2(CIGS)‐based solar cells. The ZnS was deposited by the chemical bath deposition (CBD) technique and the Zn1‐xMgxO layer by RF magnetron sputtering from ceramic targets. The [Mg]/([Mg] + [Zn]) ratio in the target was varied between x = 0·0 and 0·4. The composition, the crystal structure, and the optical properties of the resulting layers were analyzed. Small laboratory cells and 10 × 10 cm2 modules were realized with high reproducibility and enhanced stability. The transmission is improved in the wavelength region between 330 and 550 nm for the ZnS/Zn1‐xMgxO layers. Therefore, a large gain in the short‐circuit current density up to 12% was obtained, which resulted in higher conversion efficiencies up to 9% relative as compared to cells with the CdS/i‐ZnO buffer system. Peak efficiencies of 18% with small laboratory cells and 15·2% with 10 × 10 cm2 mini‐modules were demonstrated. Copyright © 2009 John Wiley & Sons, Ltd.

Study of zinc electrodes for single flow zinc/nickel battery application

Zinc deposition from alkaline zincate solution in single flow zinc/nickel battery has been investigated. The effect of different substrates such as copper, cadmium and lead were examined by using cyclic voltammetry and cathodic polarization technique. It was found that the cadmium substrate is better than the others. Zinc deposition was carried out by using galvanostatic technique, and the deposits were examined by SEM. The results demonstrated that there is no zinc dendrite on the cadmium substrate in flowing electrolyte. Coulombic and voltage efficiencies of 98 and 88%, respectively, are obtained in a small laboratory cell.

Preliminary study of single flow zinc–nickel battery

A novel redox flow battery–single flow Zn/NiOOH battery is proposed. The electrolyte of this battery for both negative electrode and positive electrode is high concentration solutions of ZnO in aqueous KOH, the negative electrode is inert metal such as nickel foil, and the positive electrode is nickel oxide for secondary alkaline batteries. Typically, there is no requirement for a membrane in the battery. Ni(OH) 2 is oxidized to NiOOH at positive electrode and the zincate ions is reduced to zinc and electroplated onto the negative electrode during charge. The reverse occurs during discharge. Results obtained with a small laboratory cell show that high efficiencies can be achieved with an average coulombic efficiency of 96% and energy efficiency of 86% over 1000 cycles. High performance obtained indicates that the single flow zinc/nickel battery is a promising battery.

Large lithium polymer battery development The immobile solvent concept

The program to develop large lithium-metal, polymer electrolyte batteries for electric traction and stand-by power is reviewed. Dry polymer electrolyte conductivity improvement through research into polymers and lithijm salts has led to a thin-film lithium polymer battery that operates in the range of 60 to 40 °C. Recent developments in large lithium polymer cell design and production are given, including preliminary results on lithium polymer cell production for the US Advanced Battery Consortium (USABC). Results of stand-by and cycle-life tests on small laboratory cells over several years are also presented confirming the electrolyte's exceptional stability in the lithium rechargeable-cell environment.

Fouling of ion-selective membranes during electrodialysis of grape must

Permselective membranes used for demineralization or concentration of natural aqueous solutions by electrodialysis become often fouled and their performance decreases. In the case of grape must, this fouling is caused by the presence of polyphenols. p]The variation of transport properties with time can be studied either in the plant for the whole stack, or for each type of membrane in the laboratory. With the first sort of study in view, we operated with a small laboratory cell. p]The instantaneous method presented here is based on the formation of a uniform deposit on the surface of membranes. p]The contribution of deposits to the total resistance of the stack is expressed as a function of time t raised to the power g, α· t g , wheras that of conductivity is given by b· t g . p]This model is in good agreement with the experimental results obtained with a small-scale laboratory apparatus.

The effect of additives on the morphology of zinc electrodeposited from a zinc chloride electrolyte at high current densities

There are advantages if zinc can be deposited electrochemically at high current densities. In order to improve the deposit at current densities exceeding 2000 Am−2, various additions were made to the electrolyte. It was found that proteinous additives produced planar deposits with a (10.2) (10.3) orientation and a current efficiency of around 85% in a small laboratory cell.

On the Anode Gas Reactions in Aluminum Electrolysis, II

The anode reaction and related secondary reactions in aluminum electrolysis have been studied in a small laboratory cell where the total amounts of anode gas could be analyzed. The primary anode product is found to be , at least at current densities above about 0.05 amp/cm2. Assuming that is formed with 100% current efficiency, a gas volume deficit of about 4% is actually observed. This deficit increases with increasing ratio in the electrolyte and with decreasing interpolar distance, and it is most likely due to a reduction of to carbon by dissolved aluminum in the electrolyte. At normal current densities does not react with the anode carbon to form . It can, however, react with the “carbon froth” formed by disintegration of the anode. A reaction between and the anode carbon is found to occur only at very low current densities, below 0.1–0.05 amp/cm2. A simple theory for the mechanism of the anode reaction is proposed.

Electrolytic Production of Sodium Perchlorate Using Lead Dioxide Anodes

Lead dioxide was investigated as an anode substitute for platinum in the production of sodium perchlorate. Rod shaped deposits were prepared on nickel and platinum clad tantalum wires. The plate was dense, heavy, metallic‐like in appearance and not too fragile for ordinary handling. The first phase of experimentation was performed in small laboratory cells to determine approximate electrolyses data. Larger bench‐scale production cells were also run simulating plant operating conditions. Lead dioxide anodes produce sodium perchlorate at high cumulative current efficiencies. One lead dioxide anode was used in cell operation for 3,000 hr. Cumulative current efficiency for a given anodic current density is a function of the cathode material, cathodic current density, and the additive used. Perchlorate can be produced using nickel, copper, stainless steel, and carbon steel cathodes. Energy requirements, under identical experimental conditions, indicate that stainless steel and nickel are the best cathode materials. A current efficiency of 91.5% was obtained with a stainless cathode at anodic and cathodic current densities of 15.5 amp/dm2 and of 7.25 amp/dm2, respectively. No unusual metallic contamination could be detected in the ammonium perchlorate prepared from the sodium perchlorate.