A battery is a device that converts chemical energy into electrical energy. Secondary batteries are rechargeable batteries that can be reused and reversible. Common secondary batteries include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries. In batteries, electrode materials are a class of conductive substances that can accept or emit electrons. In the secondary battery, the cathode refers to an electrode that can obtain electrons. Common cathode materials metal type, metal oxide type, polymer anion type and composite materials. Among the various types of secondary batteries, lithium-ion batteries are the most widely used in small batteries, flexible batteries, and high energy storage batteries.
Figure 1. Common types of Cathode Materials
- Lithium battery cathode material: A lithium battery is a secondary battery that uses a lithium-containing oxide as a cathode active material. In lithium batteries, the cathode material needs to be able to reversibly de-intercalate and intercalate lithium ions. Cathode materials mostly use layered lithium-containing transition metal oxides (eg, cobalt-based, nickel-based, cobalt/nickel/manganese ternary). These cathode materials can rapidly undergo reversible charge-discharge processes. In order to further enhance the stability of such batteries, the use of carbon materials or metal oxides combined with lithium oxides to prepare cathode materials can improve the cycle life and stability of the batteries. The optimization of cathode materials can expand the field of use of batteries, so that lithium batteries can be used in flexible batteries, small batteries, new energy vehicles and other fields.
- Other secondary battery cathode materials: Most secondary batteries use metal oxides as cathode materials. The properties of metal oxides, such as conductivity, surface area, and pore size distribution, have a great influence on battery performance. In the application of this type of electrode material, the structure of the cathode material is generally refined by increasing the specific surface area of the metal oxide and reducing the nanometer size of the metal oxide. Alternatively, inorganic materials, carbon materials or conductive polymers with good electrochemical performance are doped with metal oxides to improve the conductivity and activity of cathode materials.
- Fei Xu, Jintao Xia, Wei Shi, Shun-an Cao. Electrochemical Properties of Anthraquinone-based Polyimides as Cathodes for Lithium Secondary Batteries[J]. Chemistry Letters, 2016, 45(3), 271-273.