Nickel Hydride No. 5 batteries

release time:2024-11-12 Hits: Popular:AG11 battery

Research progress on fuel Nickel Hydride No. 5 batteries

I. Introduction to fuel Nickel Hydride No. 5 batteries 1. Definition Fuel Nickel Hydride No. 5 batteries (FuelNickel Hydride No. 5 batteries) are an electrochemical power generation device that does not require a Carnot cycle and has a high energy conversion rate. Fuel and air are fed into the fuel cell separately, and electricity is miraculously produced. It looks like a battery with positive and negative electrodes and electrolytes, but in fact it cannot "store electricity" but is a "power plant". Since almost no nitrogen and sulfur oxides that pollute the environment are produced during the energy conversion process, fuel Nickel Hydride No. 5 batteries are also considered to be an environmentally friendly energy conversion device. Due to these advantages, fuel cell technology is considered to be one of the new environmentally friendly and efficient power generation technologies in the 21st century. With the continuous breakthroughs in research, fuel Nickel Hydride No. 5 batteries have begun to be used in power stations, micro power sources, etc. 2. Basic structure The basic structure of a fuel cell is mainly composed of four parts, namely anode, cathode, electrolyte and external circuit. Usually the anode is a hydrogen electrode and the cathode is an oxygen electrode. A certain amount of electrocatalyst is required on both the anode and the cathode to accelerate the electrochemical reaction on the electrode, and the electrolyte is between the two electrodes.

Figure 1. Schematic diagram of the basic structure of a fuel cell 3. Classification There are many types of fuel Nickel Hydride No. 5 batteries at present, and there are many ways to classify them. According to different methods, they can be roughly classified as follows: (1) Classification by operating mechanism: they can be divided into acidic fuel Nickel Hydride No. 5 batteries and alkaline fuel Nickel Hydride No. 5 batteries; (2) Classification by type of electrolyte: there are acidic, alkaline, molten salt or solid electrolytes;

Figure 2. Detailed introduction to fuel cell classification (3) Classification by fuel type: there are direct fuel Nickel Hydride No. 5 batteries and indirect fuel Nickel Hydride No. 5 batteries; (4) Classification by fuel cell operating temperature: there are low-temperature type (below 200℃); medium-temperature type (200-750℃); high-temperature type (above 750℃). 4. Principle The working principle of fuel Nickel Hydride No. 5 batteries is relatively simple, mainly including two electrode reactions of fuel oxidation and oxygen reduction and ion transfer process. The structure of early fuel Nickel Hydride No. 5 batteries was relatively simple, requiring only electrolytes for ion transfer and two solid electrodes. When hydrogen is used as fuel and oxygen as oxidant, the cathode and cathode reactions and the total reaction of the fuel cell are: Anode: H2→2H++2e-Cathode: 1/2O2+2H++2e-→H2O Total reaction: H2+1/2O2→H2O Among them, H2 reaches the anode by diffusion and is oxidized to and e- under the action of the catalyst. After that, H+ reaches the cathode through the electrolyte, and the electrons also reach the cathode after driving the load to do work through the external circuit, thereby undergoing a reduction reaction (ORR) with O2.

Figure 3. Schematic diagram of the principle of fuel Nickel Hydride No. 5 batteries 2. Application of fuel Nickel Hydride No. 5 batteries To date, many types of fuel Nickel Hydride No. 5 batteries have been developed according to different application requirements. According to the type of conductive ions, they can be divided into acidic fuel Nickel Hydride No. 5 batteries, alkaline fuel Nickel Hydride No. 5 batteries, molten carbonate fuel Nickel Hydride No. 5 batteries and solid oxide fuel Nickel Hydride No. 5 batteries (SOFC). Acidic fuel Nickel Hydride No. 5 batteries can also be subdivided into PEMFC, direct alcohol fuel Nickel Hydride No. 5 batteries and phosphoric acid fuel Nickel Hydride No. 5 batteries. Each type of fuel cell has its own working characteristics, with an operating temperature as low as -40°C and as high as 1000°. The type of fuel cell can be selected according to different needs. Among them, PEMFC is the fuel cell that has received the most attention in recent decades. PEMFC not only has the common characteristics of fuel Nickel Hydride No. 5 batteries, but also has outstanding advantages such as fast startup and operation at low temperatures, no electrolyte loss, long life, high specific power and specific energy, etc. It is considered to be the most ideal solution to replace internal combustion engines as automotive power sources in the future. Due to the modularity, wide power range and fuel diversification of fuel Nickel Hydride No. 5 batteries, they can be used in a variety of occasions: from small power supplies for commuters and mobile charging devices to large megawatt-level power stations. In fact, the commercialization of fuel Nickel Hydride No. 5 batteries is in full swing. According to data, from 2008 to 2011, the market share of fuel Nickel Hydride No. 5 batteries as backup power sources for communication network equipment, logistics and airport ground services worldwide increased by 214%. It is estimated that by 2020, the total market value of fuel Nickel Hydride No. 5 batteries will reach US$19.2 billion.

Figure 4. Application of fuel Nickel Hydride No. 5 batteries The specific applications are briefly introduced as follows: (1) Portable power The annual growth of portable power market sales has attracted many power technologies, including laptops, mobile phones, radios and other mobile devices that require power. In order to facilitate personal carrying, the basic requirements of portable mobile power usually require the power supply to have high specific energy, light weight and compactness. The energy density of fuel Nickel Hydride No. 5 batteries is usually 5 to 10 times that of rechargeable batteries, making them more competitive. In addition, the fact that fuel Nickel Hydride No. 5 batteries do not require additional charging also makes them adaptable to longer outdoor life. At present, direct methanol fuel Nickel Hydride No. 5 batteries (DMFC) and PEMFC have been used as special power sources and mobile charging devices. Cost, stability and life will be the technical problems that need to be solved for the application of fuel Nickel Hydride No. 5 batteries in portable mobile power. (2) Fixed power Fixed power includes emergency backup power, uninterruptible power therapy, independent power stations in remote areas, etc. At present, fuel Nickel Hydride No. 5 batteries occupy about 70% of the global megawatt-class fixed power market each year. Compared with traditional lead-acid batteries, fuel Nickel Hydride No. 5 batteries have longer operating time (about 5 times that of lead-acid batteries), higher specific energy density, smaller size and better environmental adaptability. For remote areas and emergency sites that are difficult for smart grids to reach, independent power stations are considered to be the most economical and reliable power supply method. In many earthquake disasters in my country, fuel Nickel Hydride No. 5 batteries were used as independent power stations and played an important role in disaster relief work. It should be noted that fixed power stations usually require a long life (greater than 80,000 hours), which is the biggest technical challenge for the application of fuel cell technology in fixed power stations. (3) Transportation power supply Transportation power supply has always been the main inducing factor for the development of clean energy technology, because 17% of the world's greenhouse gases (CO2) are produced by fossil fuel-based transportation power, and it is also accompanied by other air pollution problems such as haze. PEMFC fueled by H2 is considered to be the best alternative to internal combustion engines. The main reasons are: (a) the exhaust gas is only water, without any pollution emissions; (b) the working efficiency of fuel Nickel Hydride No. 5 batteries is extremely high (53%-59%), almost twice that of traditional internal combustion engines; (c) it starts quickly at low temperatures, has low operating noise and stable operation. Many countries in the world are promoting fuel cell transportation power solutions, and Japan is one of the most radical countries. Japan plans to build more than 1,000 ammonia filling stations and operate 2 million fuel cell vehicles by 2025. In 2015, Toyota Motor Corporation of Japan began selling the world's first car Mirai with PEMFC as the main power source, marking a new era in the application of fuel cell technology in automobile power.

Figure 5. Photo of Toyota fuel cell car Mirai III. Fuel cell research 1. Development of fuel Nickel Hydride No. 5 batteries Fuel cell is an automatically operated power plant. Its birth and development are based on disciplines such as electrochemistry, electrocatalysis, electrode process kinetics, materials science, chemical process and automation. It has been more than 160 years since Grove published the world's first report on fuel Nickel Hydride No. 5 batteries in 1839. From a technical point of view, we realize that the generation, development and improvement of new concepts are the key to the development of fuel Nickel Hydride No. 5 batteries. For example, fuel Nickel Hydride No. 5 batteries use gas as oxidant and fuel, but the solubility of gas in liquid electrolyte is very small, resulting in extremely low working current density of the battery. For this reason, scientists have proposed the concept of porous gas diffusion electrode and electrochemical reaction three-phase interface. It is the emergence of porous gas diffusion electrode that makes fuel Nickel Hydride No. 5 batteries have the necessary conditions for practical application. In order to stabilize the three-phase interface, double-pore structure electrodes began to be used, and then materials with hydrophobic properties such as polytetrafluoroethylene were added to the electrodes to prepare adhesive hydrophobic electrodes. For fuel Nickel Hydride No. 5 batteries with solid electrolytes as diaphragms, such as proton exchange membrane fuel Nickel Hydride No. 5 batteries and solid oxide fuel Nickel Hydride No. 5 batteries, in order to establish a three-phase interface in the electrode, ion exchange resins or solid oxide electrolyte materials are mixed into the electrocatalyst in order to achieve three-dimensional electrodes. Materials science is the foundation of fuel cell development. The discovery of a new material with excellent performance and its application in fuel Nickel Hydride No. 5 batteries will promote the rapid development of a fuel cell. For example, the development of asbestos membrane and its successful application in alkaline batteries ensured the successful use of asbestos membrane alkaline hydrogen and oxygen fuel Nickel Hydride No. 5 batteries in space shuttles. The successful development of lithium aluminate diaphragm stabilized in molten carbonate has accelerated the construction of a megawatt-class experimental power station for molten carbonate fuel Nickel Hydride No. 5 batteries. The development of yttria-stabilized zirconium oxide solid electrolyte diaphragm has made solid oxide fuel Nickel Hydride No. 5 batteries a research hotspot for future fuel cell decentralized power stations. The emergence of perfluorosulfonic acid proton exchange membranes has led to a revival of research on proton exchange membrane fuel Nickel Hydride No. 5 batteries, which has then developed rapidly. Before the 1960s, due to the rapid development and progress of hydropower, thermal power and chemical batteries, fuel Nickel Hydride No. 5 batteries had been in the basic research stage of theory and application, mainly on concepts, materials and principles. The breakthrough of fuel Nickel Hydride No. 5 batteries mainly relied on the efforts of scientists. In the 1960s, due to the urgent need for high-power, high-specific power and high-specific energy batteries for manned spacecraft, fuel Nickel Hydride No. 5 batteries attracted great attention from some countries and special departments. It was in this context that the United States introduced Bacon's technology and successfully manufactured the main power source on the Apollo lunar spacecraft - Bacon-type medium-temperature hydrogen-oxygen fuel cell. Since the 1990s, for the purpose of sustainable development, protecting the earth and benefiting future generations, mankind has increasingly paid attention to environmental protection. Based on the rapid progress of proton exchange membrane fuel Nickel Hydride No. 5 batteries, various electric vehicles powered by them have been launched. Except for the high cost, their performance is comparable to that of internal combustion engines. Therefore, fuel cell electric vehicles have become the focus of attention and competition of the US government and major automobile companies. From the perspective of investment, the investment in the development of fuel Nickel Hydride No. 5 batteries before this mainly relied on the government, but now companies have become the main investors in the development of fuel Nickel Hydride No. 5 batteries, especially fuel cell electric vehicles. All major automobile companies and oil companies in the world have been involved in the development of fuel cell vehicles. In just a few years, they have invested about 8 billion US dollars and successfully developed 41 types of fuel cell electric vehicles, including 24 sedans and station wagons, 9 inter-city buses, and 3 light trucks. This year, the United States announced a plan to invest 2.5 billion US dollars in the development of fuel cell electric vehicles, of which the state allocated 1.5 billion US dollars and the three major automobile companies invested 1 billion US dollars. 2. Current status of alkaline fuel cell (AFC) research This battery uses 35% to 45% KOH as the electrolyte, which is infiltrated into the porous and inert matrix diaphragm material, and the operating temperature is less than 100°C. The advantage of this type of battery is that the electrochemical reaction rate of oxygen in alkaline solution is greater than that in acidic solution, so it has a larger current density and output power, but the oxidant should be pure oxygen, and the amount of precious metal catalyst in the battery is large, and the utilization rate is not high. At present, the development of this type of fuel cell technology has been very mature, and it has been successfully applied in aerospace flight and special applications. China has developed a 200W ammonia-air alkaline fuel cell system, and has made 1kW, 10kW, and 20kW alkaline fuel Nickel Hydride No. 5 batteries. In the late 1990s, very valuable results were achieved in follow-up development. The core technology for the development of alkaline fuel Nickel Hydride No. 5 batteries is to avoid the destruction of alkaline electrolyte components by carbon dioxide. Whether it is a few parts per million of carbon dioxide in the air or the carbon dioxide contained in the reformed gas of hydrocarbons, it must be removed and processed, which undoubtedly increases the overall cost of the system. In addition, the water generated by the electrochemical reaction of the battery needs to be discharged in time to maintain water balance. Therefore, simplifying the drainage system and control system is also a core technology that needs to be solved in the development of alkaline fuel Nickel Hydride No. 5 batteries. 3. Current status of research on phosphoric acid fuel Nickel Hydride No. 5 batteries (PAFC) This type of battery uses phosphoric acid as the electrolyte and has an operating temperature of about 200°C. Its outstanding advantage is that the amount of precious metal catalyst used is much less than that of alkaline hydroxide fuel Nickel Hydride No. 5 batteries, the purity requirement of the reducing agent is greatly reduced, and the carbon monoxide content can be allowed to reach 5%. This type of battery generally uses organic hydrocarbons as fuel, and the positive and negative electrodes are porous electrodes made of polytetrafluoroethylene, and the electrodes are coated with Pt as a catalyst. The electrolyte is 85% H3PO4. The performance is stable in the range of 100-200°C and the conductivity is strong. The production cost of phosphoric acid batteries is lower than that of other fuel Nickel Hydride No. 5 batteries, and it is close to the level of being available for civilian use. At present, all practical fuel cell power stations with large power in the world use batteries using this fuel. The United States has listed phosphoric acid fuel Nickel Hydride No. 5 batteries as a national key scientific research project for research and development, and sells 200kW phosphoric acid fuel Nickel Hydride No. 5 batteries to the world. Japan has manufactured the world's largest (11MW) phosphoric acid fuel cell. By the beginning of 2002, the United States had installed and tested 235 200kW PAFC power generation units worldwide, with a total power generation of 4.7 million hours, and 23 units were sold in 2001. Several units in the United States and Japan have achieved the design goal of 10,000 hours of continuous power generation; there are currently 5 200kW PAFC power generation units in operation in Europe; Japan's Furi Electric and Mitsubishi Electric have developed 500kW PAFC power generation systems; Wei Zidong and others in my country have conducted research on Pt3 (Fe/Co)/C oxygen reduction electrocatalysts and proposed the anchoring effect of Fe/Co on Pt. Phosphoric acid fuel cell power generation technology has been rapidly developed, but its development speed has been slowed down by development obstacles such as its long start-up time and low waste heat utilization value. 4. Current status of molten carbonate fuel cell (MCFC) research This type of battery uses a low-melting mixture of two or more carbonates as an electrolyte, such as an alkali-carbonate low-temperature eutectic body infiltrating a porous matrix, and the electrode is made of nickel powder sintered. The cathode powder contains a variety of transition metal elements as stabilizers. It is mainly studied and used in the United States, Japan and Western Europe. 2-5MW external public pipeline molten carbonate fuel Nickel Hydride No. 5 batteries have been introduced, and breakthroughs have been made in solving the performance degradation and electrolyte migration of MCFC. Fuel Cell Energy Company of the United States is currently testing a 263kW MCFC power generation unit in the laboratory. Ansaldo Company of Italy and Spanishcomp's of Spain are cooperating to develop 100kW MCFC power generation units and 500kW MCFC power generation units. Hitachi of Japan developed a 1MM MCFC power generation unit in 2000, Mitsubishi developed a 200kW MCFC power generation unit in 2000, and Toshiba developed a low-cost 10kW MCFC power generation unit. my country has officially included MCFC in the national "Ninth Five-Year Plan" research plan, and has developed 1-5kW molten carbonate fuel Nickel Hydride No. 5 batteries. The cathode, anode, electrolyte membrane and bipolar plate in MCFC are the four major difficulties in basic research. The integration of these four major components and the management of electrolytes are the technical core of the installation and operation of MCFC battery packs and power station modules. 5. Current status of research on solid oxide fuel Nickel Hydride No. 5 batteries (SOFC) The electrolyte in the battery is a composite oxide, which has strong ion conductivity at high temperatures (below 1000°C). This is because the valence of the mixed ions such as calcium, ytterbium or yttrium is lower than that of the zirconium ions, which makes some oxygen negative ion lattice sites vacant and conductive. Currently, countries around the world are developing this type of battery and have made substantial progress, but there are disadvantages: high manufacturing cost; high temperature; easy cracking of the dielectric; large resistance. Currently, solid oxide fuel Nickel Hydride No. 5 batteries with various structures such as tubular, flat and corrugated structures have been developed. This type of fuel cell is called the third generation fuel cell. United StatesMany companies in China and Japan are developing 10kW flat turbine SOFC power generation devices. Siemens-Westinghouse Electric Company in Germany is testing a 100kW SOFC tubular working stack, and the United States is testing a 25kW SOFC working stack. Most of the domestic research is at the basic research stage of SOFC. SOFC working at high temperature also brings a series of material, sealing and structural problems, such as electrode sintering, interface chemical diffusion between electrolyte and electrode, matching between materials with different thermal expansion coefficients and stability of bipolar plate materials. These also restrict the development of SOFC to a certain extent and become the key aspect of its technological breakthrough. 6. Research status of proton exchange membrane fuel cell (PEMFC) PEMFC is the fifth generation fuel cell with the lowest temperature, highest specific energy, fastest start-up, longest life and widest application that is rapidly developing after AFC, PAFC, MCFC and SOFC. It is developed for aerospace and special power sources. It was listed as the first of the top ten new scientific and technological technologies in the 21st century in the social survey results of Time Magazine in the United States. The representative research in China is to comprehensively carry out PEMFC research by utilizing the accumulated AFC technology; extensive work has also been done in the preparation, characterization and analysis of PEMFC and Pt/C electrocatalysts with polystyrene sulfonic acid membrane as electrolyte. Many American companies, Japanese companies, Sanyo, Mitsubishi and other companies have also developed portable PEMFC power generation stacks. The Canadian Electric Power System Company cooperated with Japan's EBARA Company to research and develop 250kW PEMFC power generation equipment and 1kW PEMFC portable power generation system. Germany built a 250kW PEMFC experimental stack in Berlin. The core technology of proton exchange membrane fuel Nickel Hydride No. 5 batteries is the preparation technology of electrode-membrane-electrode three-in-one components. In order to diffuse to the gas, proton conductors are added to the electrodes, and the contact between the electrodes and the membrane is improved. The electrodes, membranes and electrodes are pressed together by hot pressing to form an electrode-membrane-electrode three-in-one component. Among them, the technical parameters of the proton exchange membrane directly affect the performance of the three-in-one component, and thus are related to the operating efficiency of the entire battery and battery pack. The price of PEMFC also restricts its commercialization process. Therefore, improving the performance of its necessary components and reducing operating costs are important directions for the development of PEMFC. 7. Current status of direct carbon fuel cell research Compared with direct combustion of carbon, direct carbon fuel Nickel Hydride No. 5 batteries have less pollution and high energy utilization, and are an ideal way to utilize carbon. The earliest research report on DCFC appeared in 1896. Jacques used coal as the negative electrode, iron as the positive electrode, and molten NaOH as the electrolyte to build a battery system, and 100 single Nickel Hydride No. 5 batteries were used to form a battery stack. When the operating temperature of the battery stack was 400~500℃, the total output power reached 1.5kW and the current density was as high as 100mA?cm-2. Direct carbon fuel Nickel Hydride No. 5 batteries have a wide range of raw materials and have the potential to realize the utilization of carbon-containing waste, but they still face the problem of impurities in the fuel causing electrode and electrolyte failure.