CN104852073A

CN104852073A - Method for preparing positive electrolyte of all-vanadium redox flow battery through chemical synthesis method

Info

Publication number: CN104852073A
Application number: CN201510164986.0A
Authority: CN
Inventors: 陈殿磊; 吴艳民; 任凤
Original assignee: New Energy Technology Co Ltd Is Got Over By Shenzhen Ten Thousand
Current assignee: New Energy Technology Co Ltd Is Got Over By Shenzhen Ten Thousand
Priority date: 2015-04-09
Filing date: 2015-04-09
Publication date: 2015-08-19

Abstract

The invention discloses a method for preparing positive electrolyte of an all-vanadium redox flow battery through a chemical synthesis method. Through the method, a high-valence oxide which is insoluble in water is reduced to a low-valence vanadium ion which is easily soluble in water through redox reaction. The adopted chemical synthesis method mainly comprises the following steps of (1) preparing with vanadium ores; (2) preparing by reducing V2O5 through sulfur dioxide; (3) preparing by reducing V2O5 through elemental sulfur; and (4) preparing by reaction of oxides of different valences of vanadium. The activated V2O5 is diluted and reduced to pure blue VOSO4 solution, and the pure blue VOSO4 solution is just dehydrated and dried under the temperature condition of 100 DEG C. The electrolyte prepared by the method has good charge and discharge performance, and is an ideal vanadium battery electrode active material.

Description

A kind of method being prepared positive electrolyte for all-vanadiumredox flow battery by chemical synthesis

Technical field

The present invention relates to a kind of method being prepared positive electrolyte for all-vanadiumredox flow battery by chemical synthesis.

Background technology

Vanadium redox battery (VRB) receives much attention because having stored energy capacitance and power adjustable, big current and can't harm the advantages such as deep discharge, long service life, Operation and Maintenance are simple, environmental protection, obtain very large development in recent years, progressively moving towards practical.

Vanadium cell forms primarily of 3 parts: electrode material section, battery diaphragm, electrolyte, and therefore its development is also mainly by the restriction of these 3 aspects.Wherein electrolyte is the core of vanadium cell, and it is the multivalent state system of a vanadium, realizes storage and the release of vanadium cell energy.Electrolyte and the conventional batteries of vanadium cell are not quite alike, it comprises the ion (active material as vanadium cell) of the different valence state of sulfuric acid (as supporting electrolyte) and vanadium, therefore the storage performance of vanadium cell more depends on its electrolyte than other battery, require that electrolyte will have high concentration, to realize the high-energy-density of battery, there is high stability again.

Anode electrolyte of vanadium battery is V (V)/V (IV) mixed solution using sulfuric acid as supporting electrolyte, and when fully charged state, vanadium ion is pentavalent, is tetravalence completely during electric discharge.In strong acidic environment, pentavalent vanadium is often considered to flaxen VO2+ form existence, and tetravalence vanadium then exists with the VO2+ form of sapphirine.

The initial electrolysis liquid of vanadium cell generally using the sulfuric acid solution of tetravalent vanadium ion as both positive and negative polarity.After primary charging activation, positive pole is oxidized to V (V) ion.Negative pole is reduced into V (II) ion.When initial electrolysis liquid concentration is identical, the volume of anode electrolyte is 2 times of negative pole.Because in activation process, negative pole also exists the transfer of two electronics, and positive pole only has one.Although VOSO4 directly can be used as the initial electrolysis liquid of vanadium cell, its price is very expensive, is unfavorable for the large-scale promotion of vanadium cell.Because the solubility of V2O5 is very little, directly can not be dissolved in acid solution by V2O5 and produce battery electrolyte.Therefore a kind of method better preparing electrolyte must separately be sought.In the preparation process of electrolyte of vanadium redox battery, factors such as improving its concentration, stability, conductivity, electro-chemical activity and economy must be considered.

Summary of the invention

The object of the invention is to improve positive electrolyte for all-vanadiumredox flow battery concentration, stability, conductivity, electro-chemical activity and economy.

For achieving the above object, the present invention adopts following technical scheme: a kind of method being prepared positive electrolyte for all-vanadiumredox flow battery by chemical synthesis, is mainly reduced to the vanadium ion of lower valency more soluble in water by the high oxide of vanadium not soluble in water by redox reaction.The chemical synthesis adopted mainly contains several as follows:

(1) with made of stones standby containing navajoite.Because Rock coal containing alum is very abundant in China, from bone coal, extract V2O5 to produce VOSO4, as electrolyte of vanadium redox battery;

(2) with sulphur dioxide reduction V2O5 preparation.Adopt V2O5, sulfuric acid and water to be raw material, at room temperature slowly pass into pure SO2, until V2O5 all dissolves, then pass into pure CO2 and drive SO2 away, the sulfuric acid solution of VOSO4 can be obtained;

(3) with elemental sulfur reduction V2O5 preparation.Take V2O5 as raw material, by V2O5 powder and dense H2SO4 Hybrid Heating, with S powder by V2O5 electronation, V (III), V (IV) electrolyte can be prepared simultaneously;

(4) with the different valence state oxide reaction preparation of vanadium.V2O5 and V2O3 powder after refinement is mixed in vitriolization solution by a certain percentage, stirs in controlled electric furnace top heating edge, just can obtain the V (III) of corresponding proportion and V (IV) mixed solution.

Above 4 kinds of chemical synthesiss, mainly utilize reducing agent V2O5 to be reduced into VOSO4 or V (III) soluble in water and the mixed solution of V (IV).

V2O5 after activation is reduced into the VOSO4 solution of pure blue through dilution, only need dewater under the temperature conditions of 100 degree, drying.

The present invention has that syntheti c route is simple, cost is low and be easy to the advantages such as control, and meanwhile, electrolyte prepared by the method has good charge-discharge performance, is desirable vanadium battery electrode active material.

Embodiment

---namely contain navajoite made of stones standby---below for first method and specifically set forth the preparation method of electrolyte of vanadium redox battery.

First V2O5 is dissolved activation in H2SO4, then with in strong reductant make V(+5) be reduced into V(+4), solution dehydrates is dry, obtain the VOSO4nH2O of pure blue.According to the difference of the reducing agent selected in VOSO4 preparation process, following several preparation method can be divided into:

(1) V2O5---H2SO4---oxalic acid, stone acid at the tenth of the twelve Earthly Branches and sucrose, hydrazine, formic acid and Acetic, the reducing agent of the method is organic substance entirely, and reducing power is more weak, and reaction speed is slow, and has CO2 to produce, and reagent dosage is larger;

(2) V2O5---H2SO4---H2S method, H2S is Well-recovered, and reaction speed is very fast, but this gas solubility in water little (≤0.1M), toxicity is large, should not control during use;

(3) V2O5---H2SO4---Fe (-2) method, the method has introduced Fe ionic impurity, makes battery unfavorable to VOSO4;

(4) V2O5---H2SO4---SO2 (H2SO2) method, this method reducing power is strong, and reaction speed is fast, and SO2 can exist with H2SO3 form, and easy and simple to handle, excessive SO2 can discharge in dehydration.This method is one best in above 4 kinds of methods, and specific embodiment can simplify as follows.

(1) raw material:

(1) V2O5 (metallurgical grade): V2O5 content is greater than 98%, yellow solid powder;

(2) H2SO4: analyze pure, concentration 98%;

(3) H2SO3: analyze pure, SO2 content (by weight) is no less than 6%.

(2) equipment:

(1) 791 type magnetic force heating stirrer;

(2) controllable temperature electric furnace;

(3) DT-100 optical electrobalance;

(4) water-bath;

(5) electric vacuum drying oven;

(6) 2XZ-1 type rotary-vane vaccum pump.

Get the 1:1 H2SO4 solution of 10 grams of V2O5 and 39ml, when V2O5 dissolves in 1:1 H2SO4 solution, temperature about 90 DEG C, constant temperature 30 minutes, mixing speed about 800 revs/min.

Then add enough reducing agents, reduction reaction is complete leaves standstill 4 hours.

When dehydrating, when temperature reaches 100 degree, continue heating moisture gradually by evaporate to dryness, along with the rising of temperature, start have acid mist to emerge, this is because a small amount of free acid is distilled out of.Therefore, the V2O5 after activation is reduced into the VOSO4 solution of pure blue through dilution, only just can need dewater under the temperature conditions of about 100 degree, drying, also can not turn green without the need to VOSO4 solid and solution under condition of negative pressure.

For the technical staff in field of the present invention, according to technical scheme described above and design, other various corresponding change can be made, all should belong within the protection range of application claims these all changes.

Claims

1. prepared a method for positive electrolyte for all-vanadiumredox flow battery by chemical synthesis, it is characterized in that: the vanadium ion by redox reaction, the high oxide of vanadium not soluble in water being reduced to lower valency more soluble in water; The chemical synthesis adopted mainly contains several as follows: (1), with made of stones standby containing navajoite, extracts V2O5 to produce VOSO4, as electrolyte of vanadium redox battery from bone coal; (2) with sulphur dioxide reduction V2O5 preparation, adopt V2O5, sulfuric acid and water to be raw material, at room temperature slowly pass into pure SO2, until V2O5 all dissolves, then pass into pure CO2 and drive SO2 away, the sulfuric acid solution of VOSO4 can be obtained; (3) with elemental sulfur reduction V2O5 preparation, take V2O5 as raw material, by V2O5 powder and dense H2SO4 Hybrid Heating, with S powder by V2O5 electronation, V (III), V (IV) electrolyte can be prepared simultaneously; (4) with the different valence state oxide reaction preparation of vanadium, V2O5 and V2O3 powder is mixed by a certain percentage in vitriolization solution, stir in controlled electric furnace top heating edge, just can obtain the V (III) of corresponding proportion and V (IV) mixed solution.

2. prepared a method for positive electrolyte for all-vanadiumredox flow battery by chemical synthesis, it is characterized in that: the V2O5 after activation is reduced into VOSO4 solution through dilution, dehydration under the temperature conditions of 100 degree, drying.