Ningbo: Graphene was used to develop kilowatt-grade aluminum air batteries

In order to meet the needs of developing smart grids, mobile communications, electric vehicles and emergency disaster relief, it is urgent to develop new chemical power sources with high energy, low cost, small size and long life. Metal air cells(also known as metal fuel cells) are chemical power sources that directly convert the chemical energy of metal materials into electrical energy. Metal air batteries have the advantages of high energy density, low price, rich resources, green pollution, long discharge life, and safety and environmental protection. They have been listed by the state in the "13th Five-Year Plan" National Strategic Emerging Industry Development Plan. At the same time, it was also included in the "Action Plan for Energy Technology Revolution Innovation(2016-2030)" by the National Development and Reform Commission and the Energy Bureau. Only in the communications base station backup power market, according to incomplete statistics, the number of communication base stations in China in 2016 is nearly 6 million. Traditional communication base stations generally use large-capacity lead-acid batteries and diesel generators as backup power systems. At present, lead-acid batteries are used as more than 10 million units, and their volume and quality are relatively large. They are replaced once every 3 to 4 years and have a short service life. However, metal air batteries have the advantages of higher energy density(systems up to 400 Wh / kg or more), long storage time(about 15 years), long reserve time(30 ~ 50 H), and wide range of suitable temperatures(-- 20 °C ~ 60 °C). It is an excellent alternative to the lead-acid backup power supply for communication base stations. In addition, the energy density of metal air batteries is as high as 800 Wh / kg, which is more than four times that of commercial lithium-ion power batteries. It also has attractive market prospects for the application of electric vehicle extensions.

However, the development of the metal air battery industry still faces many technical bottlenecks, which affects its application and promotion. There are four reasons for this: First, the catalytic activity of oxygen reduction catalyst is not high enough, and the electrode power density needs to be improved; The second is that the air cathode polarization resistance of conventional structures is large and it is difficult to meet the high power output. Third, the metal anode self-corrosion is serious, resulting in a low anode utilization rate; The fourth is the problem of thermal runaway of the battery system, resulting in the battery system can not work for a long time. Since 2013, the lithium battery Engineering Laboratory of the Ningbo Institute of Materials Technology and Engineering of the Chinese Academy of Sciences has deployed metal air cell research. The research team has made a series of advances in graphene composite catalysts, new structure air cathode, metal anode alloying, and single battery preparation processes. The graphene composite manganese oxide catalyst and the new graphene high efficiency air cathode were used to increase the power density of the single battery by 25 %(see Figure 1), which greatly improved the comprehensive performance of the metal air battery.

Adhering to the research concept of "material to be finished, material to be finished, device to be used", the research team also conducted in-depth research on battery design and system integration technology. In 2015, a magnesium air battery power generation system with an energy density of 400 W/kg, a capacity of 3 kWh, and an output power of 300 W was successfully developed. Recently, a kilowatt-grade aluminum air battery power generation system based on graphene air cathode was successfully developed(see Figure 2). The battery system has an energy density of 510 Wh / kg, a capacity of 20 kWh, and an output power of 1,000 W. A physical demonstration showed that the battery system can simultaneously power a television set, a computer, an electric fan and 10 60W lighting bulbs(see Figure 3), initially confirming the power generation capacity of the aluminum air battery system. It is reported that the research team is actively designing and developing a 5kW class high-power aluminum air battery system for communication base station backup power supply and electric vehicle extenders.

The research team has published more than 10 SCI papers and more than 20 invention patents around the study of metal air batteries. It has the ability to prepare small tests of key materials and components, monolithic batteries, and modular battery piles, and is ready to promote the industrialization of metal air batteries in the near future. The research work was funded by the Ningbo Science and Technology Innovation Team and the Ningbo Natural Science Foundation.

The page contains the contents of the machine translation.