Nickel-Induced\nDual Carbon Networks Encapsulating\nPhase Change Materials for Photothermal Conversion and Storage

Bifunctional\nphase change materials (PCMs) with efficient energy\nstorage and photothermal conversion capabilities have tremendous potential\nto be applied in advanced thermal management. However, classical organic\nPCMs with high latent heat are challenged by poor light harvesting,\nlow thermal conductivity, and leakage risks. Here, we design a unique\ndual-carbon network with Ni nanoparticles (NPs), confined carbon nanotubes\n(CNTs) shuttling in carbon honeycombs (CH), namely, CH@Ni-CNTs, to\nencapsulate paraffin wax (PW) that can facilitate the light capture\nand photothermal conversion dynamics. Benefiting from the physical\nadsorption of the hierarchical porous structure, the obtained PW/CH@Ni-CNTs\ncomposite PCMs show a high phase change enthalpy of 131.0 J g<sup>–1</sup> and long-lasting thermal stability of up to 300 heating–cooling\ncycles. Moreover, an outstanding photothermal energy conversion efficiency\nof 96.9% is achieved due to the synergistic effect of the dual carbon\nnetwork and confined Ni NPs. The CNTs shuttled CH network affords\nmultiple reflection chambers and a thermal conductive pathway, while\nthe localized surface plasmon resonance (LSPR) effects of Ni NPs concentrate\nthe incident light energy to generate and accelerate the transport\nof active “hot electron”, thus collectively contributing\nto the excellent photothermal properties of the composite PCMs. This\nstudy presents a bifunctional Ni-induced dual-carbon network system\nfor the controllable preparation of composite PCMs, and it sheds light\non the photothermal conversion mechanisms.