Sodium-ion batteries (SIBs) can develop cost-effective and safe energy storage technology for substantial energy storage demands. In this work, we have developed manganese oxide (α-MnO 2 ) nanorods for SIB applications. The crystal structure, which is crucial for high-performance energy storage, is examined systematically for the metal oxide cathode. The intercalation of sodium into the α-MnO 2 matrix was studied using the theoretical density functional theory (DFT) studies. The DFT studies predict Na ions’ facile diffusion kinetics through the MnO 2 lattice with an attractively low diffusion barrier (0.21 eV). When employed as a cathode material for SIBs, MnO 2 showed a moderate capacity (109 mAh·g –1 at C/20 current rate) and superior life cyclability (58.6% after 800 cycles) in NaPF 6 /EC+DMC (5% FEC) electrolyte. It shows a much higher capacity of 181 mAh·g –1 (C/20 current rate) in NaClO 4 /PC (5% FEC) electrolyte, though it suffers fast capacity fading (11.5% after 800 cycles). Our findings show that high crystallinity and hierarchical nanorod morphology of the MnO 2 are responsible for better cycling performance in conjunction with fast and sustained charge-discharge behaviors.

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Two-dimensional (2D) layered carbon heterostructures with controlled porosity and high graphitic degree have attracted considerable attention in recent years. They provide a crucial role in optimizing the overall performance of different devices in various applications. Here, we have introduced a practical approach utilizing reduced graphene oxide (rGO) and metal−organic framework (MOF) synergy to achieve 2D nanoporous highly graphitic carbons. These hybrid materials have been employed for supercapacitor application and have exhibited an ∼5fold increase in capacitance (334 F g −1 ) compared to bare graphene oxide (GO) precursors. The symmetric supercapacitor device performance shows the highest specific energy of 17.6 Wh kg −1 and specific power of 25000 W kg −1 in an ionic liquid electrolyte (1-butyl-3-methylimidazolium tetrafluoroborate [bmim][BF 4 ]). The high carbon content without any impurities provides a good retention of 97.24% up to 10000 cycles. This strategy provides a versatile route for developing various multilayered electrode materials on a large scale.

Solar steam generation and supercapacitors are considered the best solutions for society's foremost issues like wastewater treatment and energy storage. Nanoporous carbons derived from the metal-organic framework are of great...

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