What happens to the lead electrode when the lead acid battery is discharged? Oxidation or reduction?

A battery is a type of battery, and its function is to store limited electrical energy and use it in a suitable place. It works by converting chemical energy into electrical energy. It uses a lead plate filled with spongy lead as the negative electrode, a lead plate filled with lead dioxide as the positive electrode, and dilute sulfuric acid as the electrolyte.

When charging, electrical energy is converted into chemical energy, and when discharging, chemical energy is converted into electrical energy. When the battery is discharged, the metal lead is the negative electrode, which undergoes an oxidation reaction and is oxidized to lead sulfate; Lead dioxide is the positive electrode, which undergoes a reduction reaction and is reduced to lead sulfate. When the battery is charged with direct current, lead and lead dioxide are generated at the two poles, respectively.

After the power supply is removed, it returns to its pre-discharge state and forms a chemical cell. Lead-acid batteries are batteries that can be charged and discharged repeatedly, and are called secondary batteries. Its voltage is 2V, and it is usually used in series with three lead-acid batteries in series, and the voltage is 6V.

The car uses 6 lead-acid batteries connected in series to form a 12V battery pack. Lead-acid batteries should be supplemented with distilled water after a period of use, so that the electrolyte remains containing 22-28% dilute sulfuric acid. When discharged, the electrode reacts as:

PBO2 + 4H+ +SO42- +2E- = PBSO4 + 2H2O Negative Reaction: PB+SO42- -2E- = PBSO4 Total Reaction: PBO2 + PB+2H2SO4 === 2PBSO4 + 2H2O (The right reaction is discharge, and the left reaction is charge.

When discharged, it is equivalent to a galvanic battery, and the lead is an inert electrode, which is of course a positive electrode, and a reduction reaction occurs! This is generally the case, but there are special cases where the nature of the electrolyte should be considered. But that rarely ......happens

Lead-acid batteries. The two poles are Pb and Pbo2, the electrolyte solution is H2SO4, and the total cell reaction is: Pb+PBO2+2H2SO4=2PbSO4+2H2O

Negative Pb: PB SO42 2E PBSO4

Cathode: PBO2 4H SO42 2E PBSO4 2H2O

During the charging and discharging of the battery, electrical energy and chemical energy.

The mutual conversion depends on the active material and the electrolyte on the plate.

Chemical reaction of sulfuric acid.

to achieve it. The active material on the positive plate is lead dioxide (PBO2), which is dark brown in color; The active material on the negative plates is spongy pure lead (PB), which is blue-gray in color.

In order to increase the capacity of the battery, multiple positive and negative plates are welded in parallel respectively to form a positive and negative plate group. When installing, the positive and negative plates are mated to each other, and the partition plate is inserted in the middle. In each cell, there is always one more negative plate than positive plate.

Matters of use. 1) Ensure adequate insulation between and around the battery and the device. Inadequate insulation measures may cause electric shock, short circuit, and heat generation.

Smoke or burning.

2) Charging application chargers, directly connected to the DC power supply may cause battery leakage, heat or burning.

3) Battery capacity due to self-discharge.

It will decrease slowly. Recharge the battery before using it after a long period of storage.

1. When discharging: positive electrode: PBO2++2E-+4+H +SO42 ==PBSO4++2H2O, negative electrode: PB-2E-++SO42 ==PBSO4.

2. When charging: cathode: PBSO4++2+E-==PB++SO42-, anode: PBSO4+2H2O-2E-===PBO2+4H++SO42-.

To sum up, lead-acid batteries.

The total reaction formula of the electrode is 2PBSO4 + 2H2O==PBO2+2 H2SO4 + PB (forward discharge, reverse charge).

The total cell response is: PB+PBO+2HSO=2PbSO+2HONegative Pb:PB2E PBSO:PBo:PBo4HSO2E PBSO2HO

The two poles of the lead-acid battery are Pb and Pbo2, the electrolyte solution is H2SO4, and the total cell reaction is: PB+PBO2+2H2SO4=2PBSo4+2H2O negative Pb:PB:PB42 2E PBSO4 cathode:

pbo2＋4h＋＋so42－＋2e－＝pbso4＋2h2o

Lead imitation and lead oxide must be reactant in the electrostatic clump decomposition reaction of lead sulfate.

The formula of Zheng Lu is as follows:

On the anode, lead loses two electrons and becomes a divalent lead ion. On the cathode, the tetravalent lead of lead dioxide will get two electrons and become divalent lead ions. When charging, it's the opposite.

Therefore, the anode lead plate in the lead-acid battery is involved in the reaction.

In the lead sulfate cell reaction, lead and lead oxide are used as anode materials at the same time to carry out different reactions. In the reaction of the anode, lead and lead oxide will undergo oxidation reaction and dissolution reaction respectively, and their reaction products and effects are different: lead oxide will be oxidized to lead dioxide, releasing electrons, thus forming an electric current; Pure limb lead seepage directly dissolves into lead ions and reacts with hydrogen ions in sulfuric acid to produce sulfuric acid and oxygen.

Therefore, lead and lead oxide do not react in the electrolytic cell reaction, but they have different reactions and play different roles.

Summary. Dear, it's a pleasure to meet your <>

In galvanic cells, the cathode is usually made of lead dioxide (PBO2). When the galvanic cell is operating, a chemical reaction occurs with PBO2 on the positive electrode, resulting in an electric current as well as a reduction product of lead dioxide (i.e., PBSO4).

Why does the positive lead dioxide in galvanic cells react.

Dear, it's a pleasure to meet your <>

In galvanic batteries, the cathode is usually simply made of lead dioxide (PBO2). When the galvanic cell is slippery, a chemical reaction occurs with PBO2 on the positive electrode, resulting in an electric current and a return of lead dioxide to the original product (i.e., PBSO4).

The process of this chemical reaction is as follows: PBO2 + SO4 2- +4H+ +2E - PBSO4 + 2H2O

In this reaction, PBO2 on the positive electrode shelter receives electrons from the negative electrode and reacts with the cations SO42- and H+ to produce PBSO4 and water.

Therefore, the lead dioxide on the positive electrode can react because it is the positive electrode in the battery, and it will accept the electrons from the positive cavity and the negative electrode in the process of careful electron conduction, thus initiating a chemical reaction.

In galvanic batteries, the positive electrode is made of lead dioxide and the negative electrode is made of pure lead. The positive and negative electrodes are connected by an electrolyte, usually sulfuric acid. In the dry core cathode, lead dioxide reacts with sulfuric acid to produce lead acid and water

PBO2 + H2SO4 + 2H+ +2E- PBSO4 + 2H2O, this process is called "discharge". In this process, electrons flow from the positive electrode to the negative electrode, so an electric current is also generated in the external circuit. Conversely, in galvanic cells, when an electric current from an external circuit passes through the cell, it prompts the pure lead of the negative electrode to react with sulfuric acid, producing hydrogen and leadbic acid

Pb + H2SO4 PBSO4 + H2O + 2H+ +2E- Since electrons need to flow from the negative electrode to the positive electrode, in this reaction the electrons flow from the external circuit to the battery, so this process is called "charging". In conclusion, the cathode lead dioxide in the galvanic battery reacts because it can produce lead-acid and water with sulfuric acid in the discharged state, and can be reduced to lead dioxide in the charged state.

The two poles of the lead-acid battery are Pb and Pbo2, the electrolyte solution is H2SO4, and the total cell reaction is: PB+PBO2+2H2SO4=2PBSo4+2H2O negative Pb:PB:PB42 2E PBSO4 cathode:

pbo2＋4h＋＋so42－＋2e－＝pbso4＋2h2o

The total reaction formula of lead-acid battery: PB+PBO2+2H2SO4=2PBSO4+2H2O. Among them, PB loses electrons, PBO2 gains electrons, and the reaction that occurs at the positive electrode should be the reaction of electron loss, which is an oxidation reaction, so the positive electrode reaction formula is Pb-2E-+SO4 2-==PbSO4.

The negative reaction formula is PB-2E + SO4 2- = PBSO4.

Under normal use, the lead-acid battery should not be over-discharged, otherwise the fine lead sulfate crystals mixed with the active substance will form a larger body, which not only increases the resistance of the plate, but also makes it difficult to re-reduce it when charging, which directly affects the capacity and life of the reservoir. Lead-acid battery charging is the reverse process of discharge.

Precautions for the use of lead-acid batteries

1. Use tools with insulating sleeves, such as pliers, lead slip, etc. The use of non-insulated tools can cause the battery to short-circuit, heat up, or burn, damaging the battery.

2. Do not place the battery in a closed room or near the fire source, otherwise it may be caused by the hydrogen released by the battery.

3. Do not use thinner, gasoline, kerosene or synthetic liquid to clean the battery. The use of the above materials will result in a cracked or leaking battery case.

4. When handling batteries with 45 volts or higher voltage, take safety measures and wear insulated rubber gloves, otherwise you may be subjected to electric shock.

5. Do not put the battery in a place where it may be flooded. If the battery is immersed in water, it may burn or injure people with electric shock.

The above content refers to Encyclopedia - Lead-acid batteries.