In this study, a room-temperature ammonia gas sensor using a ZnO and reduced graphene oxide (rGO) composite is developed. The sensor fabrication involved the innovative application of reverse offset and electrostatic spray deposition (ESD) techniques to create a ZnO/rGO sensing platform. The structural and chemical characteristics of the resulting material were comprehensively analyzed using XRD, FT-IR, FESEM, EDS, and XPS, and rGO reduction was achieved via UV–ozone treatment. Electrical properties were assessed through I–V curves, demonstrating enhanced conductivity due to UV–ozone treatment and improved charge mobility from the formation of a ZnO–rGO heterojunction. Exposure to ammonia gas resulted in increased sensor responsiveness, with longer UV–ozone treatment durations yielding superior sensitivity. Furthermore, response and recovery times were measured, with the 10 min UV–ozone-treated sensor displaying optimal responsiveness. Performance evaluation revealed linear responsiveness to ammonia concentration with a high R² value. The sensor also exhibited exceptional selectivity for ammonia compared to acetone and CO gases, making it a promising candidate for ammonia gas detection. This study shows the outstanding performance and potential applications of the ZnO/rGO-based ammonia gas sensor, promising significant contributions to the field of gas detection.

In this study, pure ZnO and Al-doped ZnO(AZO) thin films were coated onto a SiO₂ wafer using the electrostatic spray deposition (ESD) process for acetone gas detection under laboratory conditions. Voltage levels were varied to determine the optimal conditions for producing thin films with the highest uniformity. The results indicate that the optimal coating voltage for achieving the highest uniformity of the coated films is 2.9 kV for ZnO and 2.6 kV for AZO. The thin films were produced under these optimal ESD conditions by adjusting the coating time, and gas sensors were fabricated by printing electrodes using a reverse offset process on top of the thin films. Analysis of the sensing response revealed that the AZO-coated gas sensor with a 200 s deposition exhibited the best acetone-sensing ability at 300 °C, with a maximum response of 13.41 at 10 ppm. Furthermore, the fabricated gas sensors effectively detected acetone gas even at a low concentration of 2 ppm, demonstrating high selectivity in comparison to other gases.

The performance, stability, and lifespan of lithium-ion batteries are influenced by variations in the flow of lithium ions with temperature. In electric vehicles, coolants are generally used to maintain the optimal temperature of the battery, leading to an increasing demand for temperature and humidity sensors that can prevent leakage and short circuits. In this study, humidity and temperature sensors were fabricated on a pouch film of a pouch-type battery. IDE electrodes were screen-printed on the pouch film and humidity- and temperature-sensing materials were printed using a dispenser process. Changes in the capacitance of the printed Ag-CNF film were used for humidity sensing, while changes in the resistance of the printed PEDOT:PSS film were used for temperature sensing. The two sensors were integrated into a single electrode for performance evaluation. The integrated sensor exhibited a response of ΔR ≈ 0.14 to temperature variations from 20 °C to 100 °C with 20% RH humidity as a reference, and a response of ΔC ≈ 2.8 to relative humidity changes from 20% RH to 80% RH at 20 °C. The fabricated integrated sensor is expected to contribute to efficient temperature and humidity monitoring applications in various pouch-type lithium-ion batteries.

This study investigates the properties of various adhesives and assesses the effects of the coating and drying conditions of aluminum surface treatment agents on adhesion strength and chemical resistance. The adhesion between aluminum and the polymer film is improved through the application of a surface treatment agent to the aluminum surface. This study examines the initial adhesive strength of a manufactured pouch film with respect to the drying temperature and time and evaluates its adhesive strength in the presence of moisture. The results indicate that the residual moisture on the aluminum surface weakens the adhesive strength and significantly affects electrolyte resistance. A noticeable reduction in strength was observed after water spraying, when the drying temperature and time were relatively low during the initial strength measurement. Among the adhesives used for aluminum and CPP lamination, olefin adhesives exhibit less susceptibility to electrolyte effects and have higher adhesive strengths compared to urethane and ester adhesives. Leveraging these characteristics, flexible pouch cells were manufactured and their stability was evaluated. The results confirm that the flexible cells demonstrate excellent stability, exhibiting potential for application in wearable devices.