Assembling halloysite nanotubes in nickel foam with silica fibers as scaffold for efficiently encapsulating phase change materials towards solar-thermal-electric energy conversion and management

Developing highly effective phase change composites (PCMs) featuring remarkable encapsulation, energy storage, conversion and management performance is of important significance for the practical utilization of organic solid-liquid PCMs. Herein, a secondary hierarchical structure (NSH) was constructed in nickel foam (NF) with silica fiber as scaffold for supporting halloysite (HNT) with polypyrrole (PPy) modification (HNT/PPy). The introduced HNT/PPy can narrow the pore size, intensify the optical absorption, and enhance the thermal and electrical conductivity of NF, while the inserted silica fiber network can prevent HNT/PPy with small particles to drop in the pores of the NF. When polyethylene glycol (PEG) is encapsulated in the NSH, the as-prepared PEG@NSH reveals an ultrahigh encapsulation rate (up to 87 % package), good shape stability (without any leakage at 100 °C with 82 % encapsulation) and excellent solar-thermal conversion capability (93 % of absorption rate, and 95.39 % of photothermal conversion efficiency). Meanwhile, the PEG@NSH also displays a significantly improved thermal conductivity (455 % of pure PEG). Combined the PEG@NSH composite with solar-thermal-electricity (STE) conversion device, efficient and stable voltage output of 907 mV and current output of 139.8 mA can be achieved at 3kW m −2 of light intensity. This work offers a straightforward construction approach for effective package of PCMs and efficient solar-thermal-electric energy conversion and management.