Soluble Lead Flow Batteries Research Articles

Effect of carbon-foam composite-coated electrode on the power storage performance of soluble lead flow batteries

In this study, we meticulously fabricated a carbon-foam composite-coated electrode through a plating electroless copper technique, which was subsequently followed by electrodeposition of lead on a carbon-foam matrix. The investigation focused on exploring the physicochemical properties of the electrodes and the cycling performances of soluble lead flow batteries. In comparison to a conventional graphite electrode, the carbon-foam composite-coated electrode exhibited superior characteristics, including a higher specific surface area characterized (282 m2 g−1) and a higher conductivity (915.37 S cm−1). The utilization of cyclic voltammetry and electrochemical impedance spectroscopy demonstrated a notable enhancement in the reversible activity of the Pb/Pb2+ couple on the novel electrode. The porous structure of the novel electrode facilitated efficient charge dispersion between the poles and effectively suppressed the dendrite growth of the negative lead. As indicated by the result, the battery incorporating the novel electrode exhibited an energy efficiency exceeding 90.0 %, an extended charge duration of 6 h, and an elevated charge/discharge rate of 60 mA cm−2. The cell employing the CFCC-E had been successfully cycled for over 650 cycles with an average Coulombic efficiency of 94.5 % when cycled at 60 mA cm−2 for 1 h.

Properties of a Soluble Lead Flow Battery Recycled with Hydrogen Peroxide

AbstractThe service life of soluble lead flow batteries can be extended by periodic addition of H2O2, especially when it failed. However in first few cycles after H2O2 treatment, its coulombic efficiency is very low. To clarify it, the properties of electrode and electrolyte, and cycle performance have been systematically analyzed. It has been found that the negative/positive electrode reactions have serious overpotentials during early charging due to oxygen, which are produced and dissolved into the electrolyte during H2O2 treatment. With increasing the cycle number, the polarization degree decreases to the normal level of the battery. To solve it, oxygen is removed using argon after H2O2 treatment. The flow cell is normally recovered in the cycling performance. The average coulomb efficiency is 94.5±5.8 % for 500 times. After H2O2 treatment and oxygen removal, it exhibits a good cycling performance at the average coulomb efficiency of 93.9±4.2 % for another 500 times.

Life span enhancement of low cost soluble-lead-redox-flow battery using high performance meso-graphite spherules/AC anode

Limited life span and sluggish kinetics have impeded the large-scale commercialization of the emerging soluble lead flow battery (SLFB). In this perspective, we have developed a promising anode with rapid charge transport characteristics and good reversible chemical reactions. A graphite spherules-based composite anode modified with an activated carbon additive can restrain the poor electrodeposits adhesion, improve the charge transfer kinetics for more balanced redox chemistry and prevent cell failure. An optimized composite anode configuration assisted in enhanced exchange current density and demonstrated high coulombic efficiency (>80 %) with a long-life span (813 cycles), additionally generating meagre precipitation of the deposits (0.53 g). The morphological and kinetic interpretation of the cycled electrodes further elucidates that the modified SLFB anode enables faster dissolution of the Pb to Pb+2, allowing the flow battery to stock the stored capacity to meet the future energy requirements efficiently. The proof-of-concept modified anode achieved through this work would reliably open new approaches to developing better electrodes for stable and efficient SLFB systems to help modularize batteries for grid-scale exploration.

Issues Concerning Manufacture and Recycling of Lead

This article gives an overview of historical and present uses of lead against the backdrop of gradual realization that lead is an environmental hazard. In this paper the lead in the lead-acid batteries is investigated from the view of its present use. This use continues because there does not exist economical and practical alternative to lead for this purpose. In fact the use is still steadily increasing. This may not be a concern as it has been demonstrated that in countries with strong economies, recycling of lead from the batteries can near 100%. Here, we take a look at reality, by comparing select countries on both sides of the economic spectrum. In poorer countries, recycling suffers more on the safe and clean side of the process. Historical uses of lead are also reviewed, as well as a new approach of using lead compounds in soluble lead flow batteries.

Predicting the cost of a 24 V soluble lead flow battery optimised for PV applications

Providing reliable electricity from small-scale renewable power is an important challenge for emerging economies. The soluble lead flow battery (SLFB) is a promising battery for this application, as it has a simple architecture making it relatively robust, and a lifetime of 2000 cycles demonstrated at the cell level. Also, the electrolyte is manufacturable directly from spent lead acid batteries. There is a need for techno-economic models to allow the cost/performance of a complete system to be defined and optimised.Such a model is defined here for the first time and used in a multi-objective optimisation to design a 24 V system for a charging hub in Sierra Leone. A 4 h duration was found to be optimal, and electrolyte for a 3.5 kW/14 kWh system would fit in a 1000 L IBC.Methanesulfonic acid was found to be the largest cost component of the 4 h system, with graphitic bipolar plates next. Both have low raw material costs, and in an optimistic scenario a total component cost of <£50/kWh would be achieved, half that of current NMC Li-ion cells. The greatest technical risk to achieving low cost is deposit thickness of lead dioxide. This important research gap should be addressed.

Electrochemical properties of electrolyte for lead fluoroborate redox flow battery prepared with recovered lead

The electrochemical properties of electrolyte for soluble lead flow battery(SLFB) are a key factor for the improvement of its performance. Pb(BF4)2 in which Pb2+ ions are highly soluble is cheaper and more stable than conventional Pb(CH3SO3)2. This paper presents the electrochemical properties of HBF4 and Pb(BF4)2 prepared with recovered lead for the electrolytes of SLFB. The density difference of reagent grade and recovered lead electrolytes is less than 0.05 g/cm3 and their viscosities increase up to 132 %, 120 %, respectively when concentration of Pb(BF4)2 changes from zero to 2.0 mol·dm−3. The conductivity of 1.5 mol·dm−3 electrolyte prepared with recovered lead has a peak when concentration of HBF4 is less than 1.0 mol·dm−3. The results of cyclic voltammetry, linear sweep voltammetry and constant current charge/discharge test showed that impurities of recovered lead exert insignificant influences on the Pb2+/Pb and Pb2+/PbO2 reactions. These results are promising to apply recovered lead to SLFB.

Weatherability of soluble lead flow batteries using the electrolytes of Pb(CH3SO3)2 and CH3SO3H/HBF4

An electrolyte of Pb(CH3SO3)2 and CH3SO3H/HBF4 mixed acids is utilized to investigate the cycling performance of soluble lead flow batteries over the range −40 °C–50 °C. The solution containing 1.0 M Pb(CH3SO3)2 + 0.4 M CH3SO3H + 1.6 M HBF4 is optimized as the electrolyte based on its freezing point, conductivity and dynamic viscosity. At low temperature, its charge transfer resistance is lower than that in Pb(CH3SO3)2 + CH3SO3H solution. The side reactions of hydrogen and oxygen evolutions are reduced that is beneficial for the electrodeposition of PbO2 and Pb. At high temperature, the hydrolysis of HBF4 could be inhibited by CH3SO3H. The corrosion current density is reduced to effectively avoid the corrosion and failure of graphite electrodes. The coulombic efficiency of cells is maintained at 87.3 %–95.1 % within the range −40 °C–50 °C. The energy efficiency is higher than 74 %. The soluble lead flow battery exhibits an excellent weatherability.

The soluble lead flow battery: Image-based modelling of porous carbon electrodes

A novel numerical modelling framework coupling physics-based model equations and image-based input parameters is developed to simulate the behaviour of the soluble lead flow battery when reticulated vitreous carbon (RVC) electrodes are used. Experimental results are presented to validate the model. Open-source software OpenImpala is used to predict the macro-homogeneous properties of RVC from computed tomography scans of various grades of RVC. The process is repeated on manipulated datasets where a voxel dilation technique has been used to estimate the geometry of RVC electrodes with a range of thicknesses of electrodeposited material. The model predicts that with a region of free electrolyte dividing the electrodes, the electrolyte velocity is low within the electrodes. This is exacerbated by a build-up of deposit close to the inlet. By dividing the electrodes with only a porous separator, a deposit build-up is no longer seen, and the concentration within the electrodes is shown to be far more even. Finally, with an applied current density of 50 mA cm−2, the overpotential is predicted to be reduced by over 100 mV when 100 ppi RVC electrodes are used instead of 10 ppi electrodes. An experimentally validated voltage efficiency of over 80% is achieved.

Study on electrochemical properties of Pb(BF4)2 electrolyte for improvement of cycle lifetime and efficiency in soluble lead flow batteries

The electrochemical characteristics of a soluble lead flow battery are key factors for the improvement of its cyclic lifetime and efficiency. In this work, we suggested aqueous solution of Pb(BF4)2 and HBF4 as the electrolytes of soluble lead flow battery and observed the kinetic behavior of the electrode by cyclic voltammetry of the cyclic lifetime, quantum efficiency and voltage efficiency of the SLFB with respect to concentration of the electrolyte. Both the density and viscosity of the electrolyte increase with an increasing [Pb(BF4)2]. The conductivity exhibits a peak at 1.5 mol/L Pb(BF4)2 when [HBF4] is below 1.0 mol/L. According to the cyclic voltammetry, the electrode process is fast with a low overvoltage and no additional reactions for the aqueous solution with 1.5 mol/L Pb(BF4)2 and 0.25 mol/L HBF4. Overall, for the aqueous solution of 1.5 mol/L Pb(BF4)2 and 0.25 mol/L HBF4, the battery showed a best performance with the cyclic lifetime being 48 times, the average quantum efficiency 88%, the voltage efficiency 70% and the battery efficiency 62%. These results are promising for fresh parameters of the electrolyte that could play a major role for the improvement of SLFBs.

Effect of temperature on physicochemical properties of PbO2 deposits in the soluble lead flow battery

The weatherability of soluble lead flow battery is critical to its large-scale and safety application. In this work, physicochemical properties of PbO2 deposits are investigated at different temperatures, 50, 20, 0 and -20 °C. The deposit formed at low temperature has the higher discharge capacity than that formed at high temperature when they are discharged at the same temperature of 20 °C. With the temperature decreased from 50 to -20 °C, the relative content ratio of α-PbO2: β-PbO2 changes from 0: 100 to 33: 67. The non-stoichiometric ratio of Olattice: Pb in PbO2 deposits increases from 1.31 ± 0.15 to 1.67 ± 0.18. And particle sizes of PbO2 deposits become fine, from 4.29 ± 1.71 to 2.08 ± 0.93 µm, and their distributions become narrow. This indicates that physicochemical properties of PbO2 deposits can be improved by increasing activation overpotential through decreasing temperature. However, the cycling performance of batteries becomes worse at low temperature, even though the high activity PbO2 deposits is obtained after charge. It can be well explained from the limiting current-density and exchange current density of positive electrode significantly decreases with decreasing temperature.

Improvement of commercial carbon/high density polyethylene conductive composite plate with an aqueous silane treatment for soluble lead flow batteries

In this paper, γ-aminopropyltrimethoxysilane is used to improve the properties of commercial carbon/HDPE conductive composite plate. The surface chemistry of carbon fillers are characterized using X-ray Photoelectron Spectroscopy. Carbon fillers (natural flake graphite, carbon black and short carbon fiber) are treated by hydrolysis of silane to improve their compatibility with polyethylene. High-speed shearing and two-screw rotating are performed to distribute carbon fillers into the matrix. Finally the carbon/HDPE conductive composite is prepared using a hot press. Compared with the sample without silane treatment, the conductivity and flexible strength of composite plate can be enhanced by addition of hydrolyzed γ-aminopropyltrimethoxysilane, especially treated with the concentration of 2 wt% aqueous silane solution. The conductivity of NFG57.5%CB11.5%SCF4%/HDPE27% composite increases from 41.2 S/cm to 82.6 S/cm, and its bending strength from 49.3 MPa to 65.6 MPa. The sample treated with the concentration of 2 wt% silane exhibits a better electrochemical corrosion resistance than other samples treated with 0 wt%, 1.0 wt%, 3.0 wt% and 4.0 wt% silane. As the electrode of lead methanesulfonate flow batteries, the conductive composite treated with 2 wt% silane has the highest energy efficiency than other sample since due to its high conductivity, which is confirmed by electrochemical impedance spectroscopy.

A two dimensional numerical model of the membrane-divided soluble lead flow battery

Dividing the soluble lead flow battery (SLFB) is known to improve the cycle life of the SLFB by preventing failure mechanisms such as short-circuiting and by allowing electrode specific electrolyte additives. Modelling (SLFB) is a complex multiphysics problem due to the electrolyte flow, composition changes and reaction environment geometry variations associated with the deposition and dissolution of the active material as a function of state of charge. Here we studied the membrane divided SLFB using a two-dimensional, transient, numerical model, built in COMSOL Multiphysics. Divided cells using cationic and anionic ion-exchange membranes and simple, porous separators are compared with the undivided SLFB. The model successfully predicts the complex, non-linear relationship between Pb2＋ ion concentration and conductivity of the electrolyte as a function of free acid concentration. There is a deviation of less than 22 mS cm−1 between the simulated electrolyte conductivity and the experimental data. We show the conductivity of the Nafion-115 membrane in the SLFB dominated the potential drop across the membrane. However, at higher current densities, the Donnan potential becomes more dominant.

Effect of phase composition of PbO2 on cycle stability of soluble lead flow batteries

As the anodic deposited material of soluble lead flow battery, the phase composition of PbO2 is an important factor affecting the performance of battery. In this paper, the influences of current density, concentration of H+ and operating temperature on the phase composition of PbO2 are systematically studied in the aqueous solution of lead methanesulfonate / methanesulfonic acid. It has been found that the electrodeposition potential of PbO2 is affected by those three conditions, which is a main factor to produce crystal PbO2 with different phase compositions. The high potential (higher than 1.50 V vs. SCE) is beneficial to producing α-PbO2, and the low potential (lower than 1.50 V vs. SCE) is favor for the formation of β-PbO2. To avoid the cell voltage dropping down during constant current charge/discharge cycling, the constant voltage charge was applied to keep a mixture of α-PbO2 and β-PbO2 during cycling. The cycling performance of flow cell is more stable than that under galvanostatic charge/discharge conditions.

Temperature adaptability of the soluble lead flow battery using different solutions of fluoborate, perchlorate, methanesulfonate and trifluoromethanesulfonate

The evaluation of cell's weatherability is of practical interest. To further improve the soluble lead flow battery's weatherability, physiochemical properties of electrolytes containing fluoborate, perchlorate, methanesulfonate and trifluoromethanesulfonate are investigated from −60 to 50 °C. Activities of CF3SO3H and HClO4 are poor in trifluoromethanesulfonate and perchlorate solutions due to common anion effect. The solubility of lead salt can be improved by increasing temperature, but worsened by increasing acid's content. With the temperature increasing, the conductivity is enhanced, and the viscosity is lowered for four solutions. The same results have been found by increasing acid's content except for CF3SO3H. The high energy efficiency can be achieved for cells over −40–0 °C using fluoborate and perchlorate solutions, 73.2% at −40 °C and 78.1% at −30 °C respectively. Over the temperature range of 20–50 °C, the cells with methanesulfonate and trifluoromethanesulfonate solutions have good performance, 77.4% and 73.7% at 50 °C respectively.

Impact of Acetate Additive on PbO2 Plating and Oxygen Evolution in Soluble Lead Flow Batteries

Soluble lead flow batteries (SLFBs), a potential form of large-scale energy storage, are currently facing the challenge of short cycle life. We previously demonstrated that by adding sodium acetate...

Performance of soluble lead flow batteries using lead trifluoromethylsulfonate electrolyte

Abstract In lead methanesulfonate flow battery, with the charge/discharge cycling, some PbO2 drops into the electrolyte, decreasing the efficiency of the battery and limiting its service life. In this work, an aqueous solution of soluble lead trifluoromethylsulfonate is firstly proposed as a supporting electrolyte for the lead soluble flow battery. Its efficiency and the cycling stability can be improved. Compared with the Pb(CH3SO3)2/CH3SO3H electrolyte, the kinetics and reversibility of PbO2/Pb2+ are improved in the Pb(CF3SO3)2/CF3SO3H electrolyte. The charge voltage in the Pb(CF3SO3)2/CF3SO3H electrolyte is lower than that in the Pb(CH3SO3)2/CH3SO3H electrolyte at the same current density in the range of 10 - 60 mA cm−2. Moreover, the PbO2 layer deposited in the Pb(CF3SO3)2/CF3SO3H electrolyte is smooth and compact, no any PbO2 particles are observed to drop off from the positive electrode over tens of cycles. Pb particles are smaller than those deposited in the Pb(CH3SO3)2/CH3SO3H electrolyte. More impressively, the high columbic efficiency is dropped down to 80% after 244 cycles at a current density of 40 mA cm−2 by employing the Pb(CF3SO3)2/CF3SO3H electrolyte.

Development of a two-dimensional, moving mesh treatment for modelling the reaction chamber of the soluble lead flow battery as a function of state of charge for Pb and PbO2 deposition and dissolution

Abstract During cycling of the soluble lead flow battery, solid layers of lead (Pb) and lead dioxide (PbO2) are deposited and stripped from the electrode surfaces. As such, there is a change in geometry of the flow field within the battery. A detailed two-dimensional numerical model which simulates this change in geometry using a moving mesh technique is developed. The model accounts for deposition of Pb, PbO2 along with the formation of lead oxide (PbO) during discharge of the PbO2 deposit due to a side reaction which is commonly assumed in the literature. Over short time scales of around 1 hr charge/discharge periods, which are typically reported in the literature, the effect of this is small. However, over more realistic time scales (>1 hr), by applying this technique, significant differences are seen in the cell resistance and in the mass flow rate of electrolyte. As a result, a difference in cell voltage of up to 65 mV is seen over a 24 h period. The numerical results are validated against experimental data, showing an agreement in the voltage-time profile and a close fit for the moving mesh approach.

Study on the reversibility of PbOx(1&lt;&lt;2)/Pb2+ in different electrolytes containing CH3SO3−, CF3SO3−, and ClO4− for soluble lead flow batteries

• PbO 2 particles is small in the Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H electrolyte. • α-PbO 2 is tend to form in the Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H electrolyte. • Reversibility of PbO x /Pb 2+ can be improved under the function of CF 3 SO 3 − . In this work, different soluble lead electrolytes, lead methanesulfonate, lead trifluoromethylsulfonate and lead perchlorate are selected to investigate the characteristics of anodic electrodeposited materials. The charge current is large in Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H electrolyte, followed by those in Pb(ClO 4 ) 2 /HClO 4 and Pb(CH 3 SO 3 ) 2 /CH 3 SO 3 H solutions at the same positive electrode potential of 1.7 V vs. SCE. Physiochemical properties of PbO 2 , such as the particle size and its distribution, α-phase and β-phase, and the non-stoichiometry of PbO 2 are investigated using SEM, XRD and XPS. PbO 2 particles have a ball shape, which are electrodeposited in different electrolytes. Their sizes are 1.97 ± 0.84, 1.13 ± 0.35 and 1.78 ± 0.21 μm in Pb(CH 3 SO 3 ) 2 /CH 3 SO 3 H, Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H and Pb(ClO 4 ) 2 /HClO 4 electrolytes respectively. α -PbO 2 has a larger grain size than β -PbO 2 in those three electrolytes. PbO x ( x = 1.72) with the highest oxygen content is obtained in Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H electrolyte. Compared with other solutions, the reversibility of PbO x /Pb 2+ exhibits the best in Pb(CF 3 SO 3 ) 2 /CF 3 SO 3 H electrolyte, and the coulombic efficiency of 96.0 ± 0.4% is achieved.

The use of gold impregnated carbon-polymer electrodes with the soluble lead flow battery

The soluble lead flow battery (SLFB) is a hybrid redox flow battery. During charge, lead and lead dioxide are deposited onto the negative and positive electrode surfaces respectively from Pb2+ ions dissolved in a methanesulfonic acid electrolyte. Many of the challenges for the SLFB are related to these solid deposits, particularly the positive lead dioxide deposit. Gold has been shown to be an effective substrate for lead dioxide deposition. However, the prohibitively high cost of pure gold prevents its use as an electrode material. Therefore, using low mass loadings of gold at the surface of carbon-polymer electrodes is proposed. Gold impregnated carbon-polymer electrodes are tested in static electrolyte soluble lead cells. The addition of gold leaf onto the surface of the electrodes improved the peak energy efficiency by 5%. The cycle life of the cell was also improved from 13 cycles using plain electrodes to 29 cycles using the gold plated electrodes. The use of gold at the positive electrode appears to reduce the likelihood of failure due to shorting.

Extending the Lifespan of Soluble Lead Flow Batteries with a Sodium Acetate Additive.

In this report, we present a method for the construction of a soluble lead flow battery (SLFB) with an extended cycle life. By supplying an adequate amount of sodium acetate (NaOAc) to the electrolyte, a cycle life extension of over 50% is demonstrated for SLFBs via long-term galvanostatic charge/discharge experiments. A higher quality of the PbO2 electrodeposit at the positive electrode is quantitatively validated for NaOAc-added electrolyte by throwing index (TI) measurements. Images acquired by scanning electron microscopy (SEM) also exhibit more integrated PbO2 surface morphology when the SLFB is operated with the NaOAc-added electrolyte. This work indicates that electrolyte modification can be a plausible route to economically enable SLFBs for large-scale energy storage.