Types of chemical batteries
Chemical batteries can be divided into the nature of the work: primary batteries (primary batteries); secondary batteries (rechargeable batteries); lead-acid batteries. Among them: primary batteries can be divided into: paste zinc-manganese batteries, cardboard zinc-manganese batteries, alkaline zinc-manganese batteries, button zinc-silver batteries, button lithium-manganese batteries, button zinc-manganese batteries, zinc-air batteries, primary lithium-manganese batteries. Secondary batteries can be divided into: cadmium-nickel batteries, nickel-hydrogen batteries, lithium-ion batteries, secondary alkaline zinc-manganese batteries and so on. Lead-acid batteries can be divided into: open lead-acid batteries, fully sealed lead-acid batteries.
1. Zinc-manganese dry batteries
Zinc-manganese batteries, also known as Leclanche (Leclanche) batteries, is a French scientist Leclanche (Leclanche) invented in 1868 by the zinc (Zn) for the negative electrode, manganese dioxide (MnO2) for the positive electrode, the electrolyte solution using neutral ammonium chloride (NH4Cl), zinc oxide (ZnCl2), aqueous solution, surface starch, and aqueous solution. Aqueous solution of electrolyte solution using neutral ammonium chloride (NH4Cl), zinc oxide (ZnCl2), face starch or pulp layer paper as the isolation layer made of batteries called zinc-manganese batteries, due to the electrolyte solution is usually made of gel or adsorbed on other carriers and presenting the state of immobility, so it is also known as zinc-manganese dry batteries. Distinguished by the use of isolation layer for the paste and plate batteries of two kinds, plate and different electrolyte solution divided into ammonium-type and zinc-type batteries cardboard batteries of two kinds.
Dry cell with a zinc cylinder shell for the negative pole, located in the center of the top cover with a copper cap on the graphite rod for the positive pole, around the graphite rod from the inside to the outside is in order A: manganese dioxide powder (black) ------ used to absorb the hydrogen generated in the positive electrode (in order to prevent the phenomenon of polarization); B: saturated with ammonium chloride and zinc chloride as the electrolyte solution of starch paste.
The electrode reaction formula is: Negative electrode (zinc cylinder): Zn - 2e- === Zn2+
Positive electrode (graphite): 2NH4+ + 2e - === 2NH3 ↑ + H2↑
H2 + 2MnO2 === Mn2O3 + H2O
Total reaction: Zn + 2NH4+ + 2MnO2 === Zn2+ + 2NH3 + Mn2O3 + H2O
The dry cell has a voltage of about 1.5V and cannot be recharged for regeneration.
2. Alkaline zinc-manganese batteries
Developed in the mid-20th century on the basis of zinc-manganese batteries, they are an improved version of zinc-manganese batteries. The battery uses potassium hydroxide (KOH) or sodium hydroxide (NaOH) aqueous solution as the electrolyte solution, and adopts the opposite negative structure with zinc-manganese batteries, the negative electrode within the paste gel, with copper nails as a collector, positive electrode outside, active substances and conductive materials pressed into a ring connected with the battery shell, positive and negative electrodes with a special diaphragm separating the batteries made of batteries.
3. Lead-acid battery
1859 France Plante (Plante) found by the positive plate, negative plate, electrolyte, separator, container (battery tank) and other five basic parts. Lead dioxide is used as the positive active substance, lead as the negative active substance, sulfuric acid as the electrolyte, microporous rubber, sintered polyvinyl chloride, glass fiber, polypropylene, etc. for the spacer made of batteries.
Lead batteries can be discharged or recharged, generally made of hard rubber or transparent plastic rectangular shell (to prevent acid leakage); with multi-layer electrode plates, including a layer of brown lead dioxide on the positive plate, the negative is spongy metal lead, positive and negative electrodes separated by microporous rubber or microporous plastic plate (to prevent short-circuiting between the electrodes); both poles are immersed in the sulfuric acid solution. When discharged, it is a primary cell, and its electrode reaction is:
Negative pole: Pb + SO42- 2e - === PbSO4
Positive pole: PbO2 + 4H+ + SO42- + 2e -=== 2e - === PbSO4 + 2H2O
The total reaction formula is: Pb + PbO2 + 2H2SO4 ====== 2PbSO4 + 2H2O
When the discharge is carried out, the concentration of sulfuric acid solution will be reduced, when the density of the solution drops to 1.18g/ml should stop using for charging, charging for the electrolytic cell, the electrode reaction is as follows Electrolytic cell, its electrode reaction is as follows:
Anode: PbSO4 + 2H2O- 2e - === PbO2 + 4H+ + SO42-
Cathode: PbSO4 + 2e -=== Pb + SO42 -
The total reaction equation is: 2PbSO4 + 2H2O ====== Pb + PbO2 + 2H2SO4
When the density of the solution rises to 1.28g/ml, charging should be stopped.
The total reaction formula of the above process is:
Discharge
Pb + PbO2 + 2H2SO4 ====== 2PbSO4 + 2H2O
Charge
4. Silver-zinc batteries
Generally made of stainless steel in the form of a small round box, the round box consists of a positive shell and a negative shell, which is similar to the shape of the button (commonly known as the button). (commonly known as button battery). Inside the box, one end of the positive shell is filled with positive active material composed of silver oxide and graphite, and one end of the negative cover is filled with negative active material composed of zinc-mercury amalgam, and the electrolyte solution is a concentrated solution of KOH. The electrode reaction formula is as follows:
Negative electrode: Zn + 2OH- -2e-=== ZnO + H2O
Positive electrode: Ag2O + H2O + 2e- === 2Ag + 2OH
The total reaction equation of the battery is: Ag2O + Zn ====== 2Ag + ZnO
The voltage of the battery is usually 1.59V, and it has a long service life.
5. Cadmium-nickel batteries and metal hydride batteries
Both use nickel oxide or nickel hydroxide as the positive electrode, potassium hydroxide or sodium hydroxide aqueous solution as the electrolyte solution, metal cadmium or metal hydride as the negative electrode. Metal hydride batteries for the late 1980s, the use of hydrogen-absorbing alloys and the release of hydrogen reaction of the electrochemical reversibility of the invention made, is a small secondary battery leading products.
6. lithium battery
refers to the lithium metal or lithium compounds as the active substance of the battery is commonly known as lithium batteries, divided into primary lithium batteries and secondary lithium batteries.
7. Lithium-ion batteries
refers to the lithium ion can be embedded and de-embedded carbon materials instead of pure lithium as the anode, lithium compounds as the positive electrode, mixed electrolyte as the electrolyte made of batteries.
8. Hydrogen-oxygen fuel cell
This is a new type of high-efficiency, low-pollution batteries, mainly used in aerospace. Its electrode materials are generally activated electrodes, with strong catalytic activity, such as platinum electrodes, activated carbon electrodes. The electrolyte solution is generally 40% KOH solution. The electrode reaction formula is as follows:
Negative: 2H2 + 4OH- -4e-=== 4H2O
Positive: O2 + 2H2O + 4e-=== 4OH-
< p>Total reaction equation: 2H2 + O2 === 2H2O9. Molten Salt Fuel Cell
This is a kind of high-power chemical battery with very high power generation efficiency, which is close to the level of civil industrialization in a few developed countries such as Canada. According to the different fuel or molten salt used, there are many different varieties, such as natural gas, CO, --- molten carbonate type, molten phosphate type, etc., generally at a certain high temperature (to ensure that the salt is in a molten state) in order to work.
The following is an example of a CO---Li2CO3 + Na2CO3---air and CO2 type battery to illustrate:
Negative electrode reaction formula: 2CO + 2CO32--4e- === 4CO2
Positive electrode reaction formula: O2 + 2CO2 + 4e- === 2CO32-
The total reaction formula: 2CO + O2 === 2CO2
The battery's operating temperature is generally 6500C
10. seawater battery
In 1991, Chinese scientists pioneered the use of aluminum --- air --- seawater as the basis for the battery. --- air --- seawater as the material composition of a new type of battery, used as a navigational marker light. The battery to inexhaustible seawater as an electrolyte, relying on the oxygen in the air to make the continuous oxidation of aluminum and produce current. The electrode reaction formula is as follows:
Negative: 4Al - 12e- === 4Al3+
Positive: 3O2 + 6H2O + 12e- === 12OH-
The total reaction formula is: 4Al + 3O2 + 6H2O === 4Al(OH)3
The energy of this battery is 20---50 times higher than that of ordinary dry cell!
New Chemical Battery
(1) Sexual Hydrogen-Oxygen Fuel Cell
This battery uses 30%-50% KOH as electrolyte and works below 100°C. The fuel is hydrogen. The fuel is hydrogen and the oxidizer is oxygen. Its cell diagram is (-) C|H2|KOH|O2|C(+)
The cell reaction is Negative 2H2 + 4OH-4e=4H2O Positive O2 + 2H2O + 4e=4OH
Total Reaction 2H2 + O2 = 2H2O
Alkaline Hydrogen-Oxygen Fuel Cells Alkaline hydroxide fuel cells have been used in manned spacecraft in the United States since the 1960s, and have also been used in forklifts, tractor-trailers, etc., but their prospects as a civilian product are still subject to mixed reviews. Naysayers believe that the electrolyte used in the battery, KOH, reacts easily with CO2 from fuel gas or air to produce carbonates with poor electrical conductivity. In addition, although the fuel cell requires a low precious metal catalyst loading, it has a limited practical life. The affirmative argues that the fuel cell is made of cheaper materials, and when fueled by natural gas, it is less costly than the only commercially available phosphoric acid-type fuel cell.
(2) Phosphoric acid type fuel cell
It uses phosphoric acid as the electrolyte and cheap carbon material as the skeleton. In addition to hydrogen as a fuel, it is now possible to directly utilize methanol, natural gas, city gas and other inexpensive fuels, compared with alkaline hydroxide fuel cells, the biggest advantage is that it does not require CO2 processing equipment. Phosphoric acid type fuel cell has become the fastest developing and the most mature fuel cell at present, which represents the main development direction of fuel cell. At present, the world's largest fuel cell power plant is the 11MW U.S.-Japan cooperative phosphoric acid fuel cell power plant operated by Tokyo Electric Power Company, which has been running well since its completion in 1991. Of the more than 100 fuel cell power generation systems that have been put into operation in recent years, 90% are phosphoric acid type. The types of phosphoric acid type power generation systems supplied in the market are mainly 50KW or 100KW from Fuji Electric of Japan and 200KW supplied by International Fuel Cell Corporation of the U.S.
Fuji Electric has supplied more than 70 power plants with a field life of more than 100,000 hours.
The problems that remain to be solved for phosphoric acid-based fuel cells are: how to prevent catalyst agglomeration, which leads to shrinkage of the surface area and reduction of catalyst activity, and how to further reduce equipment costs.