Supercapacitors may be able to store more energy while maintaining fast charging times; however, they need low-cost and sophisticated electrode materials. Developing innovative and effective carbon-based electrode materials from naturally occurring chemical components is thus critical for supercapacitor development. In this context, biopolymer-derived porous carbon electrode materials for energy storage applications have gained considerable momentum due to their wide accessibility, high porosity, cost-effectiveness, low weight, biodegradability, and environmental friendliness. Moreover, the carbon structures derived from biopolymeric materials possess unique compositional, morphological, and electrochemical properties. This review aims to emphasize (i) the comprehensive concepts of biopolymers and supercapacitors to approach smart carbon-based materials for supercapacitors, (ii) synthesis strategies for biopolymer derived nanostructured carbons, (iii) recent advancements in biopolymer derived nanostructured carbons for supercapacitors, and (iv) challenges and future prospects from the viewpoint of green chemistry-based energy storage. This study is likely to be useful to the scientific community interested in the design of low-cost, efficient, and green electrode materials for supercapacitors as well as various types of electrocatalysis for energy production.

Globally, the demand for materials with high ultrafast charge rates yet slow discharge continues to rise which has resulted in extensive research into supercapacitors. Although the current supercapacitors can meet such demands, the high processing cost coupled with the use of toxic chemicals remains a major concern. In this study, porous graphene oxide (GO) with a unique morphology was synthesized by an improved Tour’s method for supercapacitor application using coconut shells as a precursor. The structure of the synthesized material consists of partially graphitized walls of porous GO. The surface morphology, the defects created in the GO, and the specific surface area of the as-synthesized materials were studied. When evaluated as an electrode material for supercapacitors, a specific capacitance of 173 F/g at 0.5 A/g in 0.5 M Na₂SO₄ and 139 F/g at 0.5 A/g in 2 M KOH was recorded. Moreover, a high capacitance retention of 99.3% was recorded after 1000 cycles, confirming the good cyclic stability of the synthesized electrode material. The good electrochemical performance can be attributed to the electrode material’s intrinsic structural and compositional superiorities. These findings indicate the potential of using coconut shells as a precursor for the synthesis of high-performance graphene-based supercapacitor electrodes with improved cost-effectiveness and reduced environmental impact.

Carbon black, a nano-porous material usually derived from the pyrolysis of waste tyres possesses varied particle sizes and morphology making it a viable material for several engineering applications. However, the high tendency for CB to agglomerate remains a challenge. To address this, bio-templating has been employed to produce a nanostructured porous carbon electrode material for supercapacitor applications using diatomite as a template. Diatomite-synthesized activated carbon (DSAC) was fabricated through a three-step process involving acid treatment of diatomite, thermal activation of carbon black, and bio-template synthesis. The resulting material was thoroughly characterized using XRD, Raman spectroscopy, BET analysis, and SEM imaging. Its electrochemical properties were assessed through cyclic voltammetry, galvanostatic charge–discharge, and electrochemical impedance spectroscopy. The DSAC material exhibited a high specific surface area of 266.867 m² g⁻¹, pore volume of 0.6606 cm³ g⁻¹, and mean pore radius of 1.8943 nm. The electrochemical evaluation revealed that DSAC demonstrates excellent electrochemical performance, achieving a high specific capacitance of 630.18 F g⁻¹ and retaining 94.29% capacitance after 5000 cycles at 1 A g⁻¹. The DSAC electrode is eco-friendly and a promising candidate for supercapacitor applications.