In chemical batteries, the anode is the electrode that can undergo oxidation reactions. In secondary battery materials, the anode is not only the site where electrochemical oxidation occurs, but also functions to transfer charge back into the conductive connector. Common secondary batteries include lead-acid batteries, nickel-cadmium batteries, nickel-metal hydride batteries, and lithium-ion batteries. Among them, lithium-ion batteries have developed the fastest. Common anode materials include carbon electrodes, metal electrodes, metal oxide electrodes, and metal hydride electrodes. Anode materials with good performance need to have the advantages of high electrochemical performance, long life, large power generation per unit mass, and uniform anode consumption, which can greatly improve the cycle life and capacitance of secondary batteries.
Figure 1. Several common anode materials
- Lithium-ion battery anode material: Lithium-ion battery is a kind of secondary battery with high energy density, many cycles, safe and reliable. The anode materials of lithium ion secondary batteries often use carbon materials, metal alloys, metal oxides, metal nitrides, nano-silicon and other materials. Among them, carbon material is the main material. Graphite, coke and carbon fiber are all low-cost carbon materials. The layered structure of these carbon materials is beneficial to realize the intercalation and deintercalation of lithium.
- Zinc-manganese battery anode material: Zinc-manganese battery mainly uses zinc as the anode material. In order to improve the cycle life and capacity of the battery, the performance of the battery has been greatly improved by changing the morphology and structure of the anode material by adding inhibitors.
- Nickel-cadmium battery anode material: Nickel-cadmium battery is an ideal DC power supply battery, which can be charged and discharged quickly. The anode material of the battery generally adopts metal cadmium. In order to improve the electric capacity of nickel-cadmium batteries, the anode material metal cadmium can be combined with active materials with high conductivity, thereby reducing the internal resistance and improving the utilization rate.
- Nickel-metal hydride battery anode materials: Nickel-metal hydride batteries mainly use rare earth nickel-based hydrogen storage alloys as anode materials. Both the microstructure of these materials and the alloys themselves have a dramatic effect on the performance of the battery. In order to obtain high specific energy, high specific power and excellent low temperature discharge performance, the structure and performance of anode materials are often optimized by regulating the preparation technology of hydrogen storage alloys.
- Sunghyun Lim, Ji-Hyun Kim, Yuto Yamada, Hirokazu Munakata, Young-Seak Lee, Sung-Soo Kim, Kiyoshi Kanamura. Improvement of rate capability by graphite foam anode for Li secondary batteries [J]. J. Power Sources, 2017, 355, 164-170.