Nacre-like ceramics-based phase change composites for concurrent efficient solar-to-thermal conversion and rapid energy storage

Directly absorbing sunlight and on-site storing thermal energy via phase change processes are promising to achieve efficient and fast solar-to-thermal energy storage. However, the performance is severely inhibited by intrinsically low thermal conductivity and poor optical absorption capability of phase change materials (PCMs). We propose a strategy to achieve integrated efficient solar-to-thermal conversion and ultrafast energy storage by developing nacre-like ceramics embedded with titanium nitride (TiN) nanoparticles (NPs) contained PCMs. A high thermal conductivity of 25.63 W m⁻¹ K⁻¹ compatible with large phase change enthalpy of 157.93 kJ/kg are demonstrated. The excellent performance is attributed to ordered arrangement of silicon carbide ceramics and erythritol PCMs, just like microstructure of natural nacre. Meanwhile, the solar absorptance is improved by exciting localized plasmon resonances of TiN NPs in a broad band. Combination of high thermally conductive biomimetic skeletons with volumetric absorptive PCMs leads to a prominent enhancement of solar-to-thermal energy storage rate by 864%. This work paves a way for the application of ceramics in rapid and efficient solar energy harvesting and thermal energy storage.