CN106711486B

CN106711486B - Lead flow battery electrolyte

Info

Publication number: CN106711486B
Application number: CN201611144823.7A
Authority: CN
Inventors: 吴旭; 陈渊; 纪良鑫; 董金鑫; 谢梦茹; 李金东; 杨家宽
Original assignee: Huazhong University of Science and Technology
Current assignee: Huazhong University of Science and Technology
Priority date: 2016-12-13
Filing date: 2016-12-13
Publication date: 2020-05-19
Anticipated expiration: 2036-12-13
Also published as: CN106711486A

Abstract

The invention belongs to the field of battery electrolyte, and discloses lead flow battery electrolyte, wherein a solvent of the lead flow battery electrolyte is deionized water, and a solute of the lead flow battery electrolyte comprises lead methanesulfonate and methanesulfonic acid, wherein the molar concentration of the lead methanesulfonate is 0.1-2 mol/L, and the molar concentration of the methanesulfonic acid is 0.1-1 mol/L. The electrolyte of the lead flow battery prepared by using the recycled lead powder has smaller difference in battery performance with the electrolyte prepared by using the traditional analytical pure chemical reagent, and the electrolyte suitable for the lead flow battery is prepared by using the more environment-friendly lead powder instead of the analytical pure PbO, so that the cost is reduced, and the scrapped lead-acid battery can be effectively utilized.

Description

Lead flow battery electrolyte

Technical Field

The invention belongs to the field of lead flow battery electrolyte.

Background

Lead acid batteries have since the invention now undergone a development history of over 150 years, which still dominates the secondary battery industry. At present, most domestic lead-acid storage battery manufacturing enterprises adopt lead powder as an active material of lead-acid storage batteries, and the lead powder comprises 70-80% of PbO and 20-30% of free lead (Pb and PbO)₂And Pb₃O₄) A mixture of components. Lead powder containing certain impurities can be obtained by recycling through a wet recycling process after the battery is scrapped, but the problem of treatment and disposal of the recycled lead powder is one of the problems which are urgently needed to be solved at present. The redox flow battery is a next-generation lead-acid battery under the concept of combining the redox flow battery, the manufacturing process is relatively simple, the energy storage cost is lower than that of the traditional lead storage battery, and the redox flow battery has a good application prospect in the field of large-scale energy storage.

The electrolyte is stored in a liquid storage tank as the core part of the lead flow battery and is transmitted to the interior of the battery through a pump to perform electrochemical reaction. The positive and negative electrodes simultaneously consume/release Pb during charge/discharge of the battery²⁺Ions. Pb²⁺The flow of the electrolyte can improve the solid-liquid interface mass transfer of the electrode and the power density, and simultaneously, the energy storage capacity of the lead-acid flow battery depends on Pb pumped into the reaction chamber from an external storage tank²⁺The amount of electrolyte, and therefore the nature of the electrolyte and the cost, are among the constraints that determine the scaling of lead flow batteries.

The lead methylsulfonate electrolyte in the prior art is prepared by adding PbCO₃The lead methyl sulfonate is obtained by reacting with methanesulfonic acid, but the lead methyl sulfonate prepared by the method has high cost and is not beneficial to scale-up.

Disclosure of Invention

Aiming at the defects or improvement requirements of the prior art, the invention provides the lead flow battery electrolyte, which provides an active substance for the charge and discharge process of the lead flow battery and is beneficial to solving the treatment and disposal problems of the waste lead-acid flow battery.

In order to achieve the above object, according to the present invention, there is provided a lead flow battery electrolyte characterized in that a solvent of the lead flow battery electrolyte is deionized water, and a solute comprises lead methanesulfonate and methanesulfonic acid, wherein a molar concentration of the lead methanesulfonate is 0.1mol/L to 2mol/L, and a molar concentration of the methanesulfonic acid is 0.1mol/L to 1 mol/L.

Preferably, the lead methanesulfonate is obtained by reacting lead powder obtained by recovering waste lead plaster by a wet method with methanesulfonic acid.

Preferably, the lead powder is not removed with impurities.

Preferably, the lead flow battery electrolyte is obtained by the following steps:

1) adding deionized water into the lead powder which is not removed and prepared by wet-method recovery of waste lead plaster, slowly adding methanesulfonic acid into the solution, and stirring until complete reaction;

2) filtering the solution after the reaction in the step 1) is completed to obtain a clarified filtrate, namely the lead flow battery electrolyte.

Preferably, the battery electrolyte is used in an electrolytic cell prepared by a 3D printer, and a positive electrode plate and a negative electrode plate are respectively packaged on two sides of the electrolytic cell.

In general, compared with the prior art, the above technical solution contemplated by the present invention can achieve the following beneficial effects:

(1) the lead powder adopted by the invention has stable raw material source and is beneficial to the large-scale preparation of the lead methylsulfonate electrolyte.

(2) The wet-method recovery of lead powder does not need impurity removal treatment, can be directly applied to a lead methane sulfonate flow battery, is beneficial to simplifying the recovery process, shortens the recovery flow and effectively reduces the recovery cost.

(3) The lead flow battery electrolyte provided by the invention has a simple preparation process, fully utilizes the active substances in the recovered lead powder, and effectively reduces the manufacturing and operating costs of the battery.

(4) The electrolyte of the lead flow battery prepared by using the recycled lead powder has smaller difference in battery performance with the electrolyte prepared by using the traditional analytical pure chemical reagent, and the electrolyte suitable for the lead flow battery is prepared by using the more environment-friendly lead powder instead of the analytical pure PbO, so that the cost is reduced, and the scrapped lead-acid battery can be effectively utilized.

Drawings

FIG. 1 is a Tafel diagram of electrolytes prepared from different raw materials;

FIG. 2(a) is a graph showing cyclic voltammetry tests of an electrolyte prepared from recycled un-decontaminated lead powder;

FIG. 2(b) is a cyclic voltammetry test graph of an electrolyte prepared from the recovered lead powder after impurity removal;

fig. 3 is a graph showing the variation of the content of Ba impurities in the battery CV test.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is described in further detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention. In addition, the technical features involved in the embodiments of the present invention described below may be combined with each other as long as they do not conflict with each other.

Referring to fig. 1 to 3, a lead flow battery electrolyte, a solvent of which is deionized water, and a solute of which comprises lead methanesulfonate and methanesulfonic acid, wherein a molar concentration of the lead methanesulfonate is 0.1mol/L to 2mol/L, and a molar concentration of the methanesulfonic acid is 0.1mol/L to 1 mol/L.

Further, the lead methanesulfonate is obtained by reacting lead powder obtained by recovering waste lead plaster by a wet method with methanesulfonic acid.

Further, the lead powder is not mixed with lead powder, so that the lead powder can be obtained in a large scale.

Further, the method for obtaining the electrolyte of the lead flow battery comprises the following steps:

Verification example:

analytically pure lead oxide, the recovered un-impurity-removed lead powder (R-2) and the recovered impurity-removed lead powder (R-3) are respectively used for preparing electrolyte of the lead methane sulfonate flow battery in a fume hood.

The difference of the two recovered lead powders removes the small difference in physical and chemical properties, and the main difference is that R-2 is lead powder without impurity removal, wherein the lead powder contains 1197.7mg/L Fe, 1579.7mg/L Ba and other impurities; and R-3 is lead powder after impurity removal, wherein the content of impurities such as Fe, Ba and the like is far lower than that of the impurities. Because the oxidation degrees of the two are different, and the methanesulfonic acid only reacts with PbO, the content of PbO is calculated, and a proper amount of lead powder is weighed to prepare the electrolyte, and the specific dosage is shown in Table 1.

TABLE 1 raw materials for preparing battery electrolyte (1L)

The methanesulfonic acid solution reacts only with the PbO in the lead powder, and a clear solution is obtained after filtration. Preparing electrolyte with the same components by using two lead powders, and then carrying out electrochemical test; to investigate whether it would be affected by the feedstock. Performing a linear scan test (LSV) at a speed of 1600 rpm; fig. 1 shows LSV tests of three electrolytes prepared from different lead powders and an electrolyte prepared from analytically pure raw materials, wherein the electrolytes prepared from different raw materials have small difference, the equilibrium potentials of the three electrolytes are about-370 mV and within 10mV, and other parameters show small difference. Therefore, different raw materials do not have great influence on the lead simple substance deposition and dissolution process in the electrolyte.

To investigate whether different electrolytes may differ during long-term deposition dissolution. The working electrode and the counter electrode are respectively connected with a platinum wire, and long-time cyclic voltammetry test is carried out, so that obvious redox peaks appear in the phenomenon of mutual conversion between Pb and PbSO4 in the traditional lead-acid battery. The deposition and dissolution of Pb in the methanesulfonic acid solution are different from the former, and the deposition and dissolution process of Pb occurs after the potential deviates from the equilibrium potential, so that the result shows a slope; for easy observation, the current is plotted after taking the logarithm, and fig. 2 is the test result. From the cyclic voltammetry test result, after 300 CV cycles, the two electrolytes are kept stable in property, the equilibrium potential is about-380 mV, and the two electrolytes have a certain difference from the previous test result on the rotating disc electrode, because the forced convection effect exists in the latter, the mass transfer process is influenced; while the equilibrium potentials of both R-2 and R-3 are shifted by about 30mV in the positive direction as the cycle continues, because part of the Pb will be deposited on the surface of the platinum wire and not dissolved during the CV cycle, thereby changing the conductivity of the whole system. It can therefore be concluded that the different raw materials have no effect on the process of dissolution of the Pb deposit in the electrolyte of the same composition.

The biggest difference between the electrolytes prepared from the two lead powders R-2 and R-3 is that the two lead powders contain different contents of impurities, and the contents of the impurities are greatly different, so that the electrolytes prepared by ICP (inductively coupled plasma) measurement have the impurity contents and are subjected to CV (constant voltage) cycleImpurity content in the ring process to investigate whether there is a process of impurity transfer in this process. Respectively sampling two electrolytes obtained from R-2 and R-3 in the CV circulation process, respectively taking out partial solutions at 100 times, 200 times and 300 times, and performing ICP test to analyze the content of impurities in the solutions so as to investigate whether the impurities can be transferred to Pb and PbO generated on the surface of an electrode in the Pb deposition and dissolution process₂In (1). Fig. 3 shows the variation of the content of a typical impurity Ba during CV cycles. It can be seen from the figure that the content of various impurities remains substantially uniform during the CV cycle and does not increase with the number of cycles. It can be inferred that the electrolytes prepared from different raw materials have almost no difference in properties, in which the content of impurities has no influence on the electrochemical properties, and the impurities are not transferred to the formed Pb and PbO2 during the Pb deposition dissolution. Therefore, the lead powder which is more environment-friendly can be used for replacing analytically pure PbO to prepare the electrolyte suitable for the lead-acid flow battery. The cost is reduced, and the scrapped lead-acid battery can be effectively utilized.

It will be understood by those skilled in the art that the foregoing is only a preferred embodiment of the present invention, and is not intended to limit the invention, and that any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the scope of the present invention.

Claims

1. The lead flow battery electrolyte is characterized in that a solvent of the lead flow battery electrolyte is deionized water, and a solute comprises lead methylsulfonate and methanesulfonic acid, wherein the molar concentration of the lead methylsulfonate is 0.1-2 mol/L, and the molar concentration of the methanesulfonic acid is 0.1-1 mol/L; the lead methanesulfonate is obtained by reacting non-impurity-removed lead powder obtained by recovering waste lead plaster by a wet method with methanesulfonic acid; the method for obtaining the electrolyte of the lead flow battery comprises the following steps:

2. The lead flow battery electrolyte as claimed in claim 1, wherein the battery electrolyte is used in an electrolytic cell prepared by a 3D printer, and the two sides of the electrolytic cell respectively enclose a positive electrode plate and a negative electrode plate.