Hydrogen fuel cells are different from hydrogen-oxygen fuel cells.
Hydrogen fuel cells use the chemical element hydrogen to create batteries that store energy. The basic principle is the reverse reaction of water electrolysis, supplying hydrogen and oxygen to the cathode and anode, respectively. Once the hydrogen diffuses outward through the cathode and reacts with the electrolyte, the electrons are released and reach the anode via an external charge.
Characteristics of hydrogen fuel cells:
1. No pollution
Fuel cells do not pollute the environment. This is by electrochemical reaction rather than combustion (gasoline, diesel) or energy storage (battery) - the most typical traditional backup power solution. Combustion releases pollutants such as COx, NOx, SOx gases and dust. As mentionedabove, fuel cells only produce water and heat. If hydrogen is produced from renewable energy sources (photovoltaic panels, wind energy, etc.), the entire cycle is completely emissions-free.
2. Quiet
The fuel cell operates quietly, with only approximately 55 dB of noise, which is equivalent to the level of a normal conversation. This makes the fuel cell suitable for indoor installation or where there are exterior noise restrictions.
3. High efficiency
The power generation efficiency of fuel cells can reach more than 50%. This is determined by the conversion properties of fuel cells. It directly converts chemical energy into electricity. energy without the need After the intermediate conversion of thermal energy and mechanical energy (generator).
The hydrogen-oxygen fuel cellst a promising new energy source. It generally uses hydrogen, carbon, methanol, borohydride, coal gas or natural gas fuel as the negative electrode and air oxygen as the positive electrode. . The main difference from ordinary batteries is that the active materials of ordinary batteries are pre-placed inside the battery, so the capacity of the battery depends on the amount of active materials stored while the active materials (fuel and oxidizer) fuel cells are supplied continuously; While reacting to earth input, this type of battery is actually just an energy conversion device. This type of battery has the advantages of high conversion efficiency, large capacity, high specific energy, wide power range and no need to recharge. However, due to its high cost and complex system, it islimited to certain special uses, such as spacecraft. , submarines, military, TV transfer stations, aspects such as lighthouses and buoys.
Hydrogen-oxygen fuel cells use hydrogen as a fuel as a reducing agent and oxygen as an oxidant.
Hydrogen-oxygen fuel cells are batteries that convert chemical energy into electrical energy through the combustion reaction. fuel. Primary batteries work on the same principle.
When a hydrogen-oxygen fuel cell operates, it supplies hydrogen gas to the hydrogen electrode and oxygen to the oxygen electrode. Hydrogen and oxygen pass through the electrolyte to generate water under the action of a catalyst on the electrode. At this time, there is an excess of electrons on the hydrogen electrode and they are negatively charged, and the oxygen electrode is positively charged due to the lack of electrons.ctons. Once the circuit is ignited, this combustion-like reaction process can continue.
When working, fuel (hydrogen) is supplied to the negative electrode and oxidant (oxygen) is supplied to the positive electrode. Hydrogen decomposes into positive H+ ions and e- electrons under the action of the catalyst on the negative electrode. Hydrogen ions enter the electrolyte and electrons move along the external circuit towards the positive electrode. The electrical load is connected to the external circuit. On the positive electrode, the oxygen and hydrogen ions present in the electrolyte absorb the electrons arriving at the positive electrode to form water. This is the reverse process of the water electrolysis reaction.
Hydrogen-oxygen fuel cells do not require a device to store all the reducing and oxidizing agents inside the battery.
Hydrogen fuel cell reagents-oxygen are all found outside the battery, it simply provides a container for the reaction 2H2+O2==2H2O
Hydrogen and oxygen can be supplied outside the battery
The fuel cell is a chemical battery that uses the energy released when substances undergo chemical reactions to convert it directly into electrical energy. From this point of view, it is similar to other chemical batteries such as zinc-manganese dry batteries, lead-acid batteries, etc. However, when it works, it needs to continuously supply reaction substances, fuel and oxidant, which is different from other ordinary chemical batteries. Because it converts the energy released by fuel during chemical reactions into electrical energy, it is called a fuel cell.
More precisely, a fuel cell is a “generator” that uses the reverse reaction of the electrolysis of water. Il consists of a positive electrode, a negative electrode and an electrolyte plate sandwiched between the positive and negative electrodes. Initially, electrolyte plates were formed by infiltrating electrolytes into porous plates. In 2013, they were developed to directly use solid electrolytes.
When working, fuel (hydrogen) is supplied to the negative electrode and oxidizer (air, the active ingredient is oxygen) is supplied to the positive electrode. Hydrogen is broken down into positive H+ ions and e- electrons at the negative electrode. When hydrogen ions enter the electrolyte, electrons move toward the positive electrode along the external circuit. The electrical load is connected to the external circuit. On the positive electrode, oxygen from the air and hydrogen ions from the electrolyte absorb electrons arriving at the positive electrode to form water. This is the prreverse process of the water electrolysis reaction. Water can be reused in this process and the principle of generating electricity is similar to solar cells that can be used at night.
The electrode materials of fuel cells are generally inert electrodes with strong catalytic activity, such as platinum electrodes, activated carbon electrodes, etc.
Thanks to this principle, the fuel cell can continuously transmit energy to the outside during its operation, so it can also be called a “generator”.
Generally speaking, writing the equation for the chemical reaction of a fuel cell requires careful attention to the acidity and alkalinity of the electrolyte. The electrode reaction that occurs on the positive and negative electrodes is not isolated, but is often closely related to the electrolyte solution. For example, there are two types of batterieshydrogen-oxygen fuel: acid type and alkali type:
If the electrolyte solution is alkaline or saline solution, the reaction formula of the negative electrode is: 2H2 + 4OHˉ-4eˉ == 4H20 Anode: O2 + 2H2O + 4eˉ== 4OHˉ
If the electrolyte solution is an acidic solution, the reaction formula of the negative electrode is: 2H2-4eˉ=4H+ (cation), and the positive electrode: O2+4eˉ+4H+=2H2O
In an alkaline solution, H+ cannot appear, and in an acidic solution, OHˉ cannot appear.
Red is hydrogen,Hydrogen generator to handle. If water electrolysis is used to produce oxygen, hydrogen will be produced at the same time, because the hydrogen will float to the top and collect at the top. So it is necessary to build an air pump on top of the base to pump the water. hydrogen and send it to the red hydrogen generator to produce electricity (mainly used to eliminateiner hydrogen, don't expect to use it for electricity).