Fabrication of ITO electrothermal film on curved ceramic cup bottoms and multi-electrode design for low-voltage operation

• An electrothermal ceramic cup was fabricated by depositing a transparent ITO film on the curved surface of the ceramic-teacup bottom. Powered via a multi-electrode unit, the cup exhibited high electrothermal performance at low voltage, making it directly compatible with mobile power sources such as phone chargers. • Using magnetron sputtering technology, a low-resistance (16 Ω/sq) transparent ITO electrothermal film was successfully prepared on the curved surface through fine oxygen regulation, overcoming the challenge of depositing high-quality ITO on complex curved substrates. • Innovatively, a multi-electrode unit was employed to supply power to the relatively high-resistance film (∼40 Ω/sq), achieving a high electrothermal temperature (up to 123.8°C) at low voltage (3 V). This approach addresses the narrow process window associated with fine oxygen control during the preparation of high-quality ITO electrothermal films. • The use of ITO as a transparent electrothermal film not only demonstrates stable and durable heating performance but also preserves the decorative patterns of the ceramic cup, showing strong potential for commercial applications. This study addresses the challenges associated with fabricating indium tin oxide (ITO) transparent conductive films on curved surfaces and enabling efficient low-voltage operation for electrothermal ceramic utensils. Unlike ITO films deposited on flat glass substrates, those grown on curved and uneven glazed surfaces typically exhibit higher sheet resistance (exceeding 50 Ω / sq ). To address this issue, we applied a controlled oxygen flow rate of 0.6 sccm for 20 minutes during magnetron sputtering, which yielded an ITO electrothermal film with a sheet resistance of 16 Ω / sq on the curved bottom surface of a ceramic teacup. To enhance heating power under low-voltage conditions, a multi-electrode unit was designed to supply power to the film. Based on a three-dimensional mathematical model of the curved heating surface, the contact behavior between spring electrode probes and the electrothermal film was numerically simulated. A multi-electrode unit with 12 pairs of interdigitated spiral spring electrode probes (spring constant: 28.7 N/m) was fabricated. When powered at 3 V with an electrode spacing of 15 mm, the electrothermal cup achieved a steady-state temperature of 123.8°C, a heating rate of 3.15°C/s, and a temperature non-uniformity of 4.355%. Comparative studies demonstrated that the ITO electrothermal film exhibited significantly higher stability than silver nanowire-based films, as well as excellent oxidation resistance and mechanical durability. This study provides valuable insights into the fabrication of highly conductive ITO films on curved ceramic surfaces and offers a practical strategy for achieving high electrothermal performance under low-voltage conditions using multi-electrode systems.