Sustainable Nanomaterials for Next-Generation Battery and Supercapacitor Applications

Abstract

The increasing adoption of renewable electricity, electric mobility and handheld electronics are leading to a high demand for electrochemical energy-storage materials with high performance and minimized environmental impact. In this case, a sustainable approach to the development of an electrode coated with manganese dioxide nanostructured material (MnO₂) derived from the rice-husk biomass is suggested for the preparation of the nitrogen doped porous carbon (NHC) electrode. The hydrothermal pretreatment and carbonisation and reduction-alkali activation and low-temperature deposition of MnO₂, leads to a carbon framework. With this in mind, a structural and electrochemical evaluation was organized that correlated the pore hierarchy, heteroatom functionality and defect density with the charge-storage behavior, and also looked at the dispersion of oxides. The BET surface area of the composite was found to be 965 m2g−1, the pore volume 0.69 cm3g−1 and the charge transfer resistance 0.72 Ω. With the three-electrode supercapacitor configuration, the specific capacitance of RH-NPC/MnO₂ was seen to be 421 F g⁻¹ at 1 A g⁻¹ and 76.5% at 10 A g⁻¹. A model asymmetric device achieved a capacitance of 38.5 Wh kg-1 at 250 W kg-1 with 95.4% capacitance after 10 000 cycles. For lithium-ion batteries, the composite was used for anode and exhibited a typical reversible capacity of 806 mAh g⁻¹ in the initial cycles and 750 mAh g⁻¹ after 500 cycles at 1 A g⁻¹. The phenomenon of collective behaviour is attributed to the presence of ion accessible networks of micropores and mesopores, enhanced wetting due to the presence of N/O functionalities and electron transfer within the carbon matrix and from the surface of MnO₂ via reversible surface redox reactions. The research shows the effective conversion of the agricultural residue to multifunctional nanostructured electrodes and gives the design rules for designing new generation low-carbon batteries and super capacitors.