Comparison of Lithium Batteries, Flow Batteries and Lithium Ion Capacitors

With the increasing popularity of electric vehicles and large storage battery systems for fixed positions in family and social life, after the transition of rechargeable batteries from nickel-metal hydride batteries to lithium-ion batteries is gradually completed, not only the research and development direction of lithium batteries has appeared more and more The trend of application development, and two new power storage technology routes , lithium-ion capacitors and flow batteries, have also been born. The advantages and disadvantages of these three power storage methods are compared below:

　　1. Lithium batteries work by chemical reaction of lithium ions intercalated and deintercalated back and forth between the positive and negative electrodes, so they can be combined into a variety of positive electrode materials and Negative electrode materials are used to achieve different purposes, such as high-power , high-capacity, high-temperature-resistant, long-life lithium batteries with different outstanding properties, but at the same time, lithium batteries that achieve full excellence or multiple important parameters also require new material technology. revolution. Power-type lithium batteries are currently relatively developed in Europe, America, and East Asia in the world, and the power lithium batteries include China, the United States, Japan and South Korea.

　　2. Lithium-ion capacitors are an improved variety of traditional electric double-layer capacitors . The negative electrode is the same as the lithium-ion battery, and the positive electrode uses the electrostatic capacity generated by the electric double layer effect. In this way, lithium ion capacitors not only have the advantages of high power and long life of electric double layer capacitors, but also have the characteristics of high capacity of lithium ion batteries. The reason why lithium ion capacitors have higher energy density than electric double layer capacitors is that the voltage and The electrostatic capacity increases. This effect is achieved in two ways: (1) By adding lithium ions, the voltage of the capacitor is increased from 2.5V~3V to 4V from the traditional electric double layer capacitor; (2) The negative electrode can obtain lithium ions, so the voltage is high. Compared with the original activated carbon of the electric double layer capacitor, the capacity is increased by at least 1 times.

　　3. The redox flow battery uses a diaphragm to separate the two ionic solutions, and the electrodes (positive and negative) arranged in the two solutions undergo oxidation reactions respectively with the circulating flow of the solution through the operation of the liquid storage tank with the pump and reduction reactions.

　　The energy density of flow batteries is lower than that of lithium batteries, but the output power (by adding cell stacks) and capacity (by adding vanadium solution tanks) can be easily increased, so there is a need for high power and large capacity requirements for large storage facilities. The special advantage has also become one of the future energies driven by power vehicles.