Investigation of Reaction Kinetics in Carbon Anode with Nano-Fillers through Impedance Spectroscopy

摘要

Lithium-ion batteries have been very successful in consumer electronics as viable and efficient power sources for many small and portable devices such as mobiles, laptop, watches, camcorders, PDAs, cameras and other communication devices. However, poor electronic conduction in electrodes due to an unstable and fragile conducting network of traditional conducting additives is still the limitation for large scale commercialization of this energy storage technology in automotives (such as EVs, HEVs, PHEVs, etc.) where high power density is desired frequently. In addition, poor contact due to large size of active material and sluggish kinetics makes it difficult to achieve their full theoretical capacities at a practical level. The conducting network in an electrode influences the performance of charge transfer kinetics at the electrode-electrolyte interface and ion migration through the solid electrolyte interface (SEI) layer as suggested by an earlier study. In graphitic anode, when an ion of lithium is inserted into the material, the crystal structure of the active material changes with the state of charge (SOC), and the resulting changes affect the intercalation/deintercalation reactions.