Ningbo Institute of Materials developed a kilowatt-class aluminum-air battery using graphene

In order to meet the ever-evolving smart grid, mobile communications, electric vehicles and emergency response needs, there is an urgent need to develop new chemical power sources with high energy, low cost, small size and long life. Recently, the Power Lithium Battery Engineering Laboratory of Ningbo Institute of Materials has successfully developed a kilowatt-class aluminum-air battery power generation system based on graphene air cathode. The battery system has an energy density of up to 510 Wh/kg, a capacity of 20 kWh, and an output power of 1000 W.

In order to meet the ever-evolving smart grid, mobile communications, electric vehicles, and emergency response needs, there is an urgent need to develop new chemical power sources with high energy, low cost, small size and long life. Metal-air battery (also known as metal fuel cell) is a chemical power source that directly converts the chemical energy of metal materials into electrical energy. Metal-air battery has the advantages of high energy density, low price, rich resources, green pollution-free, long discharge life, safety and environmental protection. It has been included in the '13th Five-Year' National Strategic Emerging Industry Development Plan. The National Development and Reform Commission and the Energy Administration are included in the 'Energy Technology Revolution and Innovation Action Plan (2016-2030)'. In terms of the backup power supply market for communication base stations alone, according to incomplete statistics, the number of communication base stations in China in 2016 was nearly 6 million.

Traditional communication base stations generally use large-capacity lead-acid batteries and diesel generators as backup power systems. Currently, there are more than 10 million sets of lead-acid batteries in use, both of which are relatively large in size and quality, and can be replaced within 3 to 4 years. Once, the service life is shorter. However, metal-air batteries have high specific energy density (system can reach more than 400 Wh/kg), long storage time (about 15 years), long standby time (30~50 h) and wide adaptation temperature range (-20℃~ 60℃) and other advantages, it is an excellent alternative to replace the lead-acid backup power supply of communication base stations. In addition, the energy density of metal-air batteries is as high as 800 Wh/kg, which is more than 4 times that of current commercial lithium-ion power batteries. It also has attractive market prospects in the application of electric vehicle range extenders.

Figure 1 Comparison of electrochemical performance between graphene-based cathodes and conventional cathodes

Figure 2 1000 W aluminum-air battery power generation System

Figure 3 Demonstration site of aluminum-air battery power generation system However, the development of the metal-air battery industry still faces many technical bottlenecks, which affect its application and promotion. There are four reasons for this: First, the catalytic activity of the oxygen reduction catalyst currently developed and applied is not high enough, and the electrode power density needs to be improved; second, the air cathode with conventional structure has a large polarization resistance, which is difficult to meet high power output; third, the metal anode The self-corrosion is serious, leading to low anode utilization; fourth, the thermal runaway of the battery system causes the battery system to fail to work for a long time.