Advanced strategies in electrode engineering and nanomaterial modifications for supercapacitor performance enhancement: A comprehensive review

Supercapacitors are rapidly emerging as a pivotal energy storage technology due to their high-power density, fast charging/discharging capabilities, and long cyclic life. This extensive review sheds light on the integral components of supercapacitors, emphasizing electrode materials and the diverse substrates they are interfaced with. The careful selection of appropriate electrode materials, along with their preparation and coating techniques on compatible substrates, significantly influences the performance and cost of supercapacitors. Recent research efforts have focused on enhancing supercapacitor performance by modifying various substrates with nanomaterials. This review covers a range of supercapacitor substrates, including carbon-based substrates, indium tin oxide-coated glass, fluorine-doped tin oxide-coated glass, nickel foam, stainless steel, and aluminum foil, discussing their modification with various nanomaterials such as carbon-based materials, metal oxides, metal hydroxides, metal sulfides, MOFs, COFs, MXenes, and conductive polymers. Techniques such as drop casting, electrochemical deposition, hydrothermal methods, and printing techniques are utilized for these modifications. The advantages and disadvantages of each substrate and modification process are examined, focusing on how nanomaterials impact energy storage capacity, power density, and cycling stability. Using nanomaterials increases electrode surface area, leading to higher energy density, while suitable substrates facilitate precise control over nanomaterial modifications, resulting in improved charge storage capabilities. By providing insights into the fundamental knowledge of supercapacitors and emphasizing the potential of nanomaterials and their modification methodologies on various substrates, this review paper offers valuable information for scientists and engineers in the field of energy storage.