Recent progress in polyaniline composites for high capacity energy storage: A review

•More than 170 journal articles have been reviewed.•Different polyaniline supercapacitor electrodes design, synthesis processes, mechanism and applications is studied.•Doping with metal, carbon nanotubes, graphene, and activated carbon results into high performance supercapacitors.•Relative performance of numerous polyaniline supercapacitors has been summarized.•Self-assembly, faster ion transport, high durability, increased retention rate, exquisite specific capacitance are some key characteristics of polyaniline based supercapacitors. Renewable energy storage devices are being given their share of importance owing to the depletion of non-renewable fossil fuel reserves. The supercapacitor is such an example of an energy storage device. The utilization of polyaniline (PANI) for energy storage application, either as a direct electroactive material or as a conducting agent is being widely explored in the last few decades. PANI is regarded as an exemplary electrode material due to its tunable pseudocapacitance owing to its variable oxidation state, superior theoretical capacitance, unchallenging fabrication, durable chemical stability, and reasonable cost. However, due to its considerable changes of dimensions during the release/doping of ions, low conductivity, and low surface area, pure PANI electrodes have low power density and poor mechanical properties. Nevertheless, its collaboration with materials having exquisite specific surface area, exposedness to active sites, porous structures, and good conductivity like those of carbon materials along with some metals might be a potent approach to the problem. In this review, the recent advances on design, fabrication processes, mechanism, and application of PANI based supercapacitors with other electrochemically active carbon materials along with some metals is discussed. [Display omitted]