The consumption of electrical energy grows alongside the development of global industry. Generating energy storage has become the primary focus of current research, examining supercapacitors with high power density. The primary raw material used in supercapacitor electrodes is activated carbon (AC). To improve the performance of activated carbon, we used manganese dioxide (MnO2), which has a theoretical capacitance of up to 1370 Fg−1. The composite-based activated carbon with a different mass of 0–20% MnO2 was successfully introduced as the positive electrode. The asymmetric cell supercapacitors based on activated carbon as the anode delivered an excellent gravimetric capacitance, energy density, and power density of 84.28 Fg−1, 14,88 Wh·kg−1, and 96.68 W·kg−1, respectively, at 1 M Et4NBF4, maintaining 88.88% after 1000 test cycles.

The development of materials and electrochemical energy storage (EES) technologies are currently taking the lead and showing excellent performance in the global effort to tackle the issues of sustainable energy supply. Supercapacitors have been widely studied among the EES technologies as they exhibit quick charging rates under high‐power conditions. Manganese dioxide (MnO2) has attracted renewed interest as a promising material due to its high theoretical capacitance and high energy density. However, the widespread application is immediately impacted by low conductivity. Hence, combining nanomaterials and various morphologies of MnO2 can improve the electrochemical performance of supercapacitors. This paper presents a review based on the composites of nanomaterials/MnO2 with various morphologies. Their mechanism and practical applications in supercapacitors are introduced in detail. Finally, the challenges and next steps in developing MnO2 electrode materials are proposed.

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Silver nanowires (AgNWs) are promising materials due to their flexibility, high transmittance, high conductivity, and low sheet resistances to replace ITO (Indium Thin Oxide) based electrodes. In this work, we studied the Propylene Glycol and Glycerol addition in Ethylene Glycol solvent to form AgNWs with polyol method. AgNWs was made thin film by spin coating method (with 1 – 3 layers variation) in PET substrate at 3000 rpm. The best morphology AgNWs formed by EG: PG: Gliserol (7 : 0 : 3) solvent composition with average diameter, length, and thickness are 210.32 nm, 6.68 μm, and 2.1 μm respectively. In optical properties, transmittance of AgNWs thin film was in range of 54.6 – 70.6 %. The sheet resistance of 3 layers AgNWs thin film was 2.8 – 30.2 Ω/sq. Sheet resistance of AgNWs thin film was better than ITO-PET (transmittance 60% sheet resistance 45 Ω/sq).

Application of energy storage systems such as supercapacitors can not be separated from the magnetic fields effect. In the last decade, it’s rare to find research reports about various low magnetic field effects on supercapacitor performance. Asymmetric supercapacitors based on MnO2-Carbon were made to analyze its electrochemical performance changes by magnetic field in 0-50 mT. Magnetic field was applied in flow direction from cathode (MnO2-C) to anode (C) during electrochemical performance test using Galvanostatic Charge-Discharge (C-D) instrument. The electrochemical performance was increasing in charging (91%) and discharging (22%) time of asymmetric supercapacitors. Impressively, the 50 mT magnetic field showed a high specific capacitance of 61.9 F/g at 0.1 A/g. The supercapacitor system delivers specific energy (17.8 Wh/kg), specific power density (329.72 W/kg), and outstanding stability (79% in 50 cycles). The electrochemical improvement by magnetic field indicates a highly promising application of this method in future supercapacitor devices.

Chemical reactions simulation in detecting hydrogen gas (H2) on Pt80Au14Ti6 sensor surface based on work function change (Δɸ) has been conducted. The simulation result is compared with laboratory results of detecting H2 gas. Three chemical reactions contained three coverages, H coverage (θH), O coverage (θO), and H2O coverage (θH2O). The simulation was run using MATLAB. This research can find the reaction parameter values such as the Arrhenius coefficient of H2O forming reaction on Pt (υf3Pt), H2O forming reaction on Au (υf3Au), i.e., H2O dissociation on Au (υf3Au ), O2 desorption on Ti (υd2Ti), H2O forming reaction on Ti (υf3Ti), and H2O dissociation on Ti (υf3Ti), i.e., 7.5×1014 s–1, 9.85×1015 s–1, 3.25×1015 s–1, 7.11×1015 s–1, 3.425×1015 s–1 and 2.725×1015 s–1, respectively. The simulation results also have the same trend as the laboratory results. However, the contact potential difference (CPD) simulation result, i.e., –240 mV, is not the same as the laboratory result, (–297± 9) mV. In addition, this simulation also obtained approximation coverage for atoms/molecules on PT80Au14Ti6 surface, i.e., θH = 0.665154 Mono Layer (ML); θO = 1.5621× 10–6 ML; and θH2O = 5.41676 ×10–5 ML.

Since energy storage is an essential component of global energy development, starting with batteries, fuel cells, and supercapacitors, it is an important topic of particular concern. Supercapacitors continue to be developed due to their high power density when compared to batteries, despite all of the benefits and drawbacks of the three. Activated carbon (AC) is materials that frequently utilized as a supercapacitor electrode due to the high surface area. Metal oxides such as manganese dioxide (MnO2) with high teoritical specific capacitance which loaded in activated carbon will caused an improvement on supercapacitors electrochemical performance. The composite was fabricated using blending method with a mass difference of MnO2, then deposited on a porous Ni-foam substrate. Ni-foam pores play as main role on the process of transferring electrolyte ions in the system so that the AC/MnO2 has, resulting a supercapacitor based AC-MnO2 15% nanocomposite with a gravimetric capacitance, energy density and power density of 79 F/g at 1 A/g, W/kg and Wh/kg respectively. The cell could maintain up to 93% after 100 cycles.