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• Sulfur/few-layer graphene (S/FLG) composite, as a cathode material with high sulfur. • Defects and edges found in FLG-OH as polysulfide reservoirs for shuttle effect. • S/FLG-OH shows a high specific capacitance of 157.4 F g−1. • When applied as a cathode host on a coin cell it obtained a voltage of about 2.6 V. • Cell with S/FLG-OH as the cathode shows a stable potential over 50 cycles. Over the past years, significant advantages have been introduced to upgrade the performance of lithium-sulfur battery (Li-S) batteries since their prototype in the 1960s. Due to high theoretical energy density and cost efficiency, Li-S batteries have obtained great attention and have made great progress in the last few years. In this work, we developed the sulfur-attached few-layer graphene composite (S/FLG), sulfur-attached functionalized few-layer graphene using acetic acid (S/FLG-COOH) and sulfur-attached functionalized few-layer graphene using strong acid H 2 SO 4 and HNO 3 (S/FLG-OH) as a cathode material with high sulfur loading. The material's structure is confirmed through XRD. The surface morphology is confirmed through SEM and elemental composition has been obtained through EDAX. The functional groups are confirmed through FTIR. The defect level and number of layers are confirmed through Raman characterization with an excitation laser wavelength of 532 nm. The electrochemical performance of three cathodes is also identified through EIS, CV, and GCD characterization. Meanwhile, highly developed defects and edges found in the functionalization of few-layer graphene using the strong acid (H 2 SO 4 and HNO 3) which consists of a hydroxyl functional group (FLG-OH) serve as polysulfide reservoirs to mitigate the shuttle effect. Among these cathodes, S/FLG-OH shows a high specific capacitance of 157.4 F g−1 and when applied as a cathode host on a coin cell it obtained a voltage of about 2.6 V. Well-performed S/FLG-OH cathode was used to fabricate the Coin Cell. The fabricated Coin Cell with S/FLG-OH as the cathode shows a stable potential over 50 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Stainless-steel (SS) coin-cell parts are more vulnerable to corrosion than the Al. • SS degradation can accelerate the corrosion of Al current collectors. • Galvanic electron transfer from Al to SS can corrode the Al metal. • MD simulations verify SS and Al's corrosion mechanisms in the imide electrolyte. • SS and Al-free pouch cells with carbon current collector show improved cyclability. F-containing functional electrolytes have been extensively investigated to improve the performance of Li-metal batteries as they generate stable LiF-based solid–electrolyte interphase layers, improving Li deposition/dissolution efficiency. However, these imide-based electrolytes corrode not only the Al current collector but also the stainless steel (SS) component of the coin cell at high operating voltages. Additionally, deciding upon which part of the corrosion has a greater effect on the performance degradation remains a topic of debate. In this study, through systematic cell design exposing SS to LiFSI-based electrolyte, it is found that SS corrosion is a more dominant cause of capacity fading than the Al case. Moreover, the computational study reveals that the electron transfer from Al to SS decomposes FSI– and the resulting byproducts finally corrode Al. To develop stable cells by removing corrosion factors, the SS and Al-free pouch-type cells are proposed by integrating carbon current collectors and locally high-concentration electrolyte and exhibit 430 cycles with a coulombic efficiency of 99.93%. This study demonstrates the importance of careful selection of cell components and systematic cell design to ensure a robust interface at the cathode side, suggesting the necessity to develop a new testing cell to replace the current coin-cell platform. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bismuth manganese oxide nanoflakes are synthesised by one step hydrothermal method. • Kinetics of charge transfer was explained using different techniques. • The diffusion and capacitive controlled contribution are differentiatedon the basis of CV data. • Coin cell device is fabricated for good performance practical application. Binary metal oxides are deposited via simple chemical routes for high-performance energy storage applications. In this work, we developed nanostructures of BiMnO 3 on Ni foam using a hydrothermal method. Initially, the (0 1 0) and (1 1 0) planes confirmed the presence of the BiMnO 3 phase. Snow fungus-like nanostructure was transferred to porous interconnected nanoflakes with an increase in deposition time. These nanoflakes serve as large active sites that are beneficial for the diffusion of electrolytic ions that enhance the charge storage and transport process. Consequently, the two-dimensional interconnected nanoflakes showed a high diffusion coefficient, standard rate constant, and minimum transfer coefficient. In addition, BiMnO 3 exhibited an aerial capacitance of 6000 mF cm−2 (1500 Fg−1) with an energy density of 102 Wh kg−1 at an applied current density of 20 mA cm−2. For practical applications, an asymmetric coin cell (ACC) device was assembled using BiMnO 3 as the positive electrode and activated carbon as the negative electrode in 3 M aqueous KOH as an electrolyte. The fabricated ACC device had an energy density of 14.4 Wh kg−1 at a power density of 50 W kg−1 with a 1.2 V potential; the capacitive retention was 90 %, with 97 % Coulombic efficiency up to 5000 cycles. Accordingly, the results determined that BiMnO 3 can be used as an electrode material for high-performance energy storage applications. [ABSTRACT FROM AUTHOR]