Functional nanofibres for electrochemical energy storage

Advanced rechargeable batteries are emerging electrochemical energy storage systems. Functional nanofibres play an essential role as novel materials to improve battery performance. This chapter presents an overview of the use of functional nanofibres in various types of energy storage systems, including lithium-ion batteries (LIBs), sodium-ion batteries (SIBs), lithium-sulfur (Li-S) batteries, and lithium-oxygen (Li-O2) batteries in addition to supercapacitors. Lithium-ion batteries are the most used energy storage system for electronic devices due to their high energy density, long cycle lifetime, low self-discharge behavior, and no memory effect. Although SIBs have limitations such as low specific capacity and poor cycling stability, they are an attractive alternative to LIBs due to the abundance of sodium resources. In contrast, Li-S batteries have the merits of low cost and high theoretical specific capacity. Still, there are some challenges to overcome, such as the high electrical resistance of sulfur, huge volume expansion, the “shuttle” effect of polysulfides, and self-discharge behavior. Li-O2 batteries provide notably higher energy densities (close to that of gasoline) compared to traditional intercalation-based chemistries. Additionally, supercapacitors are a different energy storage system that is finding increasing applications in hybrid electric vehicles, digital communication devices, flexible wearable electronics, and large industrial equipment. Compared to rechargeable batteries, supercapacitors provide substantially higher power density, faster charge-discharge cycles, and longer service life. Despite the promise of new battery and supercapacitor technologies, numerous challenges remain. Therefore, using unique nanofibres to develop high-performance electrodes, electrolytes, and separators, is paving the way toward improved energy storage systems.