Sodium-ion batteries (SIBs) are potential candidates for the replacement of lithium-ion batteries to meet the increasing demands of electrical storage systems due to the low cost and high abundance of sodium. Sodium superionic conductor (NASICON) structured materials have attracted enormous interest in recent years as electrode materials for safer and long-term performance of SIBs for electric energy storage smart grids. These materials have a threedimensional robust framework, high redox potential, thermal stability, and a fast Na + -ion diffusion mechanism. However, NASICON has low intrinsic electronic conductivity, which limits the electrochemical performance. This review describes the structural features of NASICONs to illustrate the ion storage mechanism and electrochemical performance of SIBs. Details of the NASICON crystal structure, the affiliated Na + -ion diffusion mechanism, morphology, and electrochemical performance of these materials in sodiumion half-cells as well as full cells are described. In addition to the application as electrode materials, the use of NASICONs as solid electrolytes is also elaborated in solid-state SIBs. Based on these aspects, we have provided more perspectives in terms of the commercialization of SIBs and strategies to overcome the limitations of NASICONs. Hence, this review is expected to provide the researchers of energy storage with an in-depth understanding of NASICON materials with the knowledge of structural features, which will provide a new avenue on the practicality of SIBs.

Non-platinum-based critically and rationally fabricated electrocatalysts show promising efficiency in electrochemical oxygen evolution reaction (OER) due to their reliability and costeffectiveness. Herein, a hydrothermally designed oxygen-defective Sm 2 O 3 /Fe 2 O 3 composite with gyroid morphology provides superior active sites with high porosity and mass charge transport in a catalytic system. All of the fabricated materials were characterized via different analytical techniques. The Sm 2 O 3 / Fe 2 O 3 hierarchical composite displays an outstanding lower overpotential (272 mV) to attain a current density of 10 mA/ cm 2 and a lower Tafel slope (75 mV/dec) compared to the individual materials Sm 2 O 3 and Fe 2 O 3 in alkaline media. The remarkable electrocatalytic intrinsic OER performance of oxygendefective Sm 2 O 3 /Fe 2 O 3 is ascribed to the strong synergistic effect among both materials due to their unique gyroid structure, and such architecture exhibits extraordinary electrical properties due to its porous structure. Hierarchical Sm 2 O 3 /Fe 2 O 3 exhibits marvelous activity and stability at an applied potential (0.7 V) with a slight decrease in current density. All of the extraordinary results acquired from electrochemical activity make Sm 2 O 3 /Fe 2 O 3 a promising electrocatalyst for electrochemical energy generation.

Nanostructured ZnO has gained a lot of interest as a suitable material for various applications, especially sensing, energy conversion, and storage. ZnO nanostructures can be synthesized in several ways. It is one of the materials that can be prepared in a variety of morphologies including hierarchical nanostructures. This review article presents a review of current research activities on the growth of ZnO Nanorods. The article covers various water-based routes of synthesis and is further characterized by the type of substrate used for the growth. The growth factors involved in the hydrothermal and chemical bath deposition methods are discussed. These factors include the variety of precursors, time, temperature, and the seeding method employed. At the end, applications such as gas sensing and improvement in Opto-electric properties are discussed.

Conductive polymers have become a remarkable candidate for electrode materials of supercapacitors. Polyaniline (PANI) is the most promising contender for supercapacitors because of its easy method of synthesis, low cost, and higher choice in the improvement of energy storage applications. The main issue in the use of PANI in supercapacitors is its lower stability. In this work, PANI@Fe−Ni codoped Co 3 O 4 (PANI@FNCO) nanocomposite has been prepared by in situ addition of 10 wt % FNCO as fillers in the PANI matrix. The nanocomposites were then characterized via scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy, thermogravimetric analysis, and differential scanning calorimetry to observe the morphology, crystal structure, functional groups, and thermal stability of samples, respectively. SEM results showed that FNCO was fairly dispersed in the PANI matrix, while XRD results showed a broad peak for nanocomposites because of the semicrystalline nature of polymers. The electrochemical properties of the samples were analyzed via cyclic voltammetry, galvanostatic charge and discharge, and electrochemical impedance spectroscopy. PANI@FNCO nanowires are found to overcome the shortcomings in electrochemical energy storage devices by exhibiting a higher value of specific capacitance of 1171 F g −1 and energy density of 144 W h kg −1 at a current density of 1 A g −1 . Moreover, the FNCO nanowires also showed a cyclic charge/ discharge stability of 84% for 2000 cycles.