Carbon-metal network boosting photon/phonon transport in photothermal phase change materials

The pivotal attributes of high light absorption and thermal conductivity are paramount for initiating photothermal conversion and storage within phase change materials (PCMs). However, previous photothermal initiators predominantly harness single- or dual-dimensional hybrid frameworks, the exploration of multidimensional engineering design remains scarce. Herein, we constructed multidimensional heterogeneous carbon-metal interconnected network integrating three-dimensional carbon foam (CF), one-dimensional carbon nanotubes (CNTs), and zero-dimensional Co nanoparticles via in-situ chemical synthesis and high-temperature carbonization protocols. This obtained hierarchical heterogeneous carbon-metal hybrid, when endowed with phase change properties via stable encapsulation of PCMs, exhibits remarkable thermal energy storage without liquid leakage and photothermal conversion capacity. The integration of localized surface plasmon resonance-active Co nanoparticles and photophilic CF/CNTs carbon hybrid confers excellent broadband full-spectrum sunlight absorption to composite PCMs. The cobalt-catalyzed interconnected multidimensional carbon-metal network with low interfacial thermal resistance facilitates fast transport of photons and phonons in composite PCMs. Resultantly, carbon-metal hybrid based composite PCMs synergistically yield an ultrahigh photothermal conversion efficacy of 97.07 %, a stable high voltage output of 246.9 mV, and robust cyclic operational stability. Our proposed multidimensional engineering design strategy offers new insights into the development of next-generation high-performance photothermal PCMs.