Critical review on recent developments in conducting polymer nanocomposites for supercapacitors

With the rapid depletion of fossil fuels and rising energy demand, the production and usage of renewable energy sources are gaining a lot of attraction. However, current renewable energy production must be accompanied by appropriate and efficient energy storage technologies. In this regard, energy storage technologies such as supercapacitors (SCs) are considered as potential energy storage devices. SCs have inferior energy densities than commercial batteries despite their small size, excellent power management, extended life, and high capacity and throughput. As the energy density varies in direct proportion to capacitance, the electrode materials play a pivotal role in defining the performance of SCs. Many investigators have concentrated on the synthesis of suitable electrode materials in recent years, however most of them are based on single molecules. In view of its numerous advantages, including ease of synthesis, excellent conductivity, and flexibility, conducting polymers (CPs) are employed as an electrode material in SCs. Nonetheless, due to their structure and features, the sole use of CP-based electrodes results in low specific capacitance and poor cycle stability. However, combining them with other nanomaterials like metal oxides and carbon forms can improve their electrical and mechanical properties, and thereby their capacity and energy density. This paper outlines recent breakthroughs in CPs such as polyaniline, polypyrrole, polythiophene and its derivative poly(3,4-ethylenedioxythiophene) as SC electrodes, to address the society's energy needs. Here, we present a comprehensive overview of various promising approaches toward key accomplishments in recent years.