An overview, methods of synthesis and modification of carbon-based electrodes for supercapacitor

The review work is designed to aid the novice researchers working in the energy storage discipline precisely in carbon-based supercapacitors (CSCs). Our intent is to promote and explore the idea of supercapacitor (SC), principles implicated in energy storage mechanisms, material components involved in designing/assembling a SC, the modifications of carbon electrodes, nano-size and bulk scale synthesis approach, theoretical investigation on the device parameters and thereby, setting an experimental procedure to derive superior energy outcome in CSCs. The review uniquely assess the porous carbonaceous nanostructures which are currently dwelling higher potential towards the charge storage mechanisms either as electrical double layer or pseudocapacitor depending on the degree of oxidation (carbon / oxygen ratio) present in electrode materials. The hierarchical nanostructures obtained through physical, chemical and biological synthesis methods can scale high storage capability through multiple disciplinary approach. The various issues, challenges, and factors influencing the electrochemical performance of CSCs are theoretically analyzed and predicted by new improved methods of simulation techniques and further, the same are implemented in the experimental studies with detailed investigations and evaluations. The tabular columns justifying, summarizing, and comparing the electrochemical performance of modified CSCs energy outcomes outlined from the recent 2020 and 2021 published articles are discussed. Lastly, the review concludes with the new perspectives for future research involving CCSs with the two-dimensional (2D) compounds known as MXene, metal-organic frameworks (MOF), and carbon-nitride as electrode materials.