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Solar-Based Smartphone Charging Stations with Voltage, Current, and Power Monitoring Noer, Zikri; Fathurrahman, Muhammad; Siregar, Annisa Novita Putri; Awanda, Misuki; Agus, Muhammad Abduh Akram; Siahaan, Lolo Ferdinan
Journal of Technomaterial Physics Vol. 5 No. 2 (2023): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v5i2.13348

Abstract

Renewable energy sources continue to be developed as alternative energy sources to reduce the use of fossil energy sources. One of them is a solar power plant that uses a light source from sunlight. For the public, electrical energy is useful to support work and communication activities such as using smartphones, but not many chargers are found in public places to charge smartphone batteries. It has designed and implemented a smartphone charging station to charge smartphone batteries using solar power. The smartphone battery charging on this smartphone charging station can display voltage, current, and power when charging the battery; this tool is equipped with an INA219 sensor, ATmega328 microcontroller, and solar power to make this tool look smart. The purpose of making this tool is to find out the working principle, voltage, current, and power and compare the charging time of the smartphone battery between the smartphone charging station and the manufacturer's charger. The working principle, when this tool charges the smartphone battery, the INA219 sensor receives output value data in the form of current and voltage. Furthermore, the sensor sends a signal to the ATmega328 to be converted and displayed as data on the LCD so that users can see the output value. The test results of the tool, when charging a smartphone battery using Micro USB, showed the average values of voltage, current, and power, respectively, of 11.7 volts, 0.48 amperes, and 5.98 watts. USB Type C shows the average voltage, current, and power values of 11.33 volts, 0.71 amperes, and 8.37 watts, respectively. The comparison of the duration of battery charging time on the manufacturer's Micro USB with the smartphone charging station has a difference of 27 minutes; the comparison of the duration of the smartphone battery charging time using the manufacturer's USB Type C with the smartphone charging station has a difference of 22 minutes.
Cycle Voltametry Performance of Nitrogen-Doped Reduced Graphene Oxide Derived from Oil Palm Empty Fruit Bunch for Sodium-Ion Batteries Sihombing, Gunawan; Yamin, Octo Muhammad; Noer, Zikri; Lubis, Hariyati; Agus, Muhammad Abduh Akram; Idamayanti, Dewi
Journal of Technomaterial Physics Vol. 7 No. 1 (2025): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v7i1.18305

Abstract

This study investigates the electrochemical performance of nitrogen-doped reduced graphene oxide (NRGO) derived from oil palm empty fruit bunches as an anode material for sodium-ion batteries (SIB). The aim is to evaluate the potential of NRGO to enhance sodium-ion storage through cyclic voltammetry (CV) analysis. The NRGO was synthesized using a modified Hummers method followed by nitrogen doping through thermal treatment under an ammonia atmosphere. Cyclic voltammetry measurements were conducted at scan rates of 0.2 mV/s, 1 mV/s, and 10 mV/s to analyze the redox behavior and charge storage capacity. At a low scan rate of 0.2 mV/s, the current response was minimal, indicating limited sodium-ion intercalation. At 1 mV/s, the current increased, suggesting enhanced ionic mobility, though no distinct redox peaks were observed, implying a primarily capacitive mechanism. At the highest scan rate of 10 mV/s, the current response increased further, but the absence of clear redox peaks persisted, indicating limited faradaic reactions. The initial CV cycles showed a higher current due to the formation of a solid electrolyte interphase (SEI) layer and structural rearrangements, which stabilized in subsequent cycles. The overall charge storage mechanism appears to be dominated by double-layer capacitance rather than faradaic processes. These findings suggest that NRGO derived from oil palm empty fruit bunches exhibits moderate electrochemical performance as a SIB anode material. While the material demonstrates promising charge storage capabilities, further optimization is required to enhance redox activity. Future research should focus on improving synthesis conditions, such as increasing nitrogen doping levels and enhancing surface area, to achieve better electrochemical performance and make NRGO a viable candidate for sodium-ion battery applications.
Influence of Mode of Hydrothermal Treatment and Precursor State on Phase Formation and Crystallinity of Sodium Titanate Wulandari, Ervina Putri; Noer, Zikri; Rianna, Martha; Humaidi, Syahrul; Agus, Muhammad Abduh Akram; Nazwariva, Alya; Rambe, Jihan Murtadha
Journal of Technomaterial Physics Vol. 8 No. 1 (2026): Journal of Technomaterial Physics
Publisher : Talenta Publisher

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.32734/jotp.v8i1.24729

Abstract

Sodium titanate was synthesized via a sol–gel-assisted hydrothermal method to study phase evolution and crystallinity under different hydrothermal treatment conditions and precursor compositions. Four processing routes were designed: continuous hydrothermal treatment (24 h), interrupted hydrothermal cycles (3 × 8 h), dried-gel hydrothermal treatment, and fresh-gel hydrothermal treatment. X-Ray Diffraction (XRD) was used to analyze the resulting crystal phases and crystallite sizes. Continuous treatment of fresh gel produced monoclinic Na₂Ti₆O₁₃ with small crystallites (12.4 nm), while interrupted processing increased crystallite size to 15.5 nm. Pre-drying of the sol–gel precursor prior to continuous hydrothermal treatment yielded well-defined Na₂Ti₆O₁₃ with enhanced crystallinity and larger crystallites (27.6 nm). In contrast, insufficient precursor stabilization redirected phase evolution toward monoclinic Na₂TiO₃ despite comparable crystallite size. The results demonstrate that the hydrothermal treatment mode primarily governs crystallite growth, whereas the precursor state controls phase selectivity. These findings provide a clear synthesis–structure relationship for tailoring sodium titanate materials.