Band-selective high-emissivity ceramic-based photonic crystal infrared heating devices

Achieving band-selective control of infrared emissivity is crucial for enhancing electric heating efficiency and minimizing energy loss in non-targeted spectral regions, such as lithium battery drying. Here, this work reports a photonic crystal infrared radiation heater (PC-IRH) that integrates an ITO/Ag/glass powder composite heating layer with a three-dimensional TiO 2 photonic crystal coating. Unlike conventional broadband infrared heaters or high-emissivity ceramic coatings, the PC-IRH uses the photonic band-gap effect of ordered TiO 2 microspheres to spectrally reshape the broadband thermal radiation generated by the underlying heating layer, selectively suppressing radiation in non-target bands while concentrating emission in the absorption window of the target material. TiO 2 microspheres synthesized via the sol-gel method, were deposited onto an ITO/Ag composite heating layer via screen printing, repeated roll-pressing, and high-temperature sintering to form a three-dimensional photonic crystal (PC) structure. By controlling the microsphere diameter and designing based on Bragg's law, the PC-IRH achieves an average emissivity of 91.1% and a peak of 99.4% in the 5.0∼9.6 μm range, and reaches thermal steady state within approximately 20 s. In NMP solvent drying tests, the PC-IRH reduces energy consumption by 18.4% and drying time by 28.7%, while significantly enhancing the mechanical properties of the resulting PVDF films. This work establishes a versatile strategy for material-specific, spectrally selective infrared heating with broad potential in energy-efficient thermal management and precision industrial processes.