Polyaniline-based electrodes: recent application in supercapacitors and next generation rechargeable batteries

This review highlights the versatility of polyaniline (PANI) for application in the electrodes of energy storage devices — supercapacitors and next-generation batteries (sodium-ion — SIB and lithium–sulfur — LiS). Supercapacitor electrodes with high energy storage capability and cycle life have been developed based on both neat PANI as well as its composites with carbon or inorganic pseudocapacitors. In batteries, tailorable synthesis of PANI to confine/coat nanostructures of electroactive materials (Na+ host materials in SIBs or sulfur in LiS) has resulted in notable improvement in utilization, stability and durability of these materials due to PANI's high conductivity, specific material interaction and its ability to ameliorate stress on the nanostructures caused by large volume changes during cycling. Limitations of PANI in such electrodes are discussed and possible future directions have been proposed.