In-situ synthesis of nanoporous nickel/carbon composite foam to encapsulate the phase change materials for energy management

Abstract

A novel polymerized high internal phase emulsion (polyHIPE) containing nickel precursor (Ni-PolyHIPEs) have been developed as a platform to in-situ synthesis of nanoporous nickel/carbon composite foams (NiCC). The well-distributed nickel nanoparticles with a size of 50 ± 10 nm in the carbon matrix were detected. The presence of nickel as simultaneous graphitization agent and metallic filler in the initial polymeric backbone led to a highly electrical/thermal conductive framework owing to growth of large graphitic regions in the microstructure. In the synthesized composite, the size of the cells and windows were 6.2 and 1.3 μm. In addition to three dimensionally (3D) interconnected macroporous structure, abundant nanopores are created in the pore walls. The 3D interconnected nanoporous foamy structure of the graphitic composites lend themselves as an excellent encapsulation reservoir for phase change materials (PCMs) applications. The PCMs composites revealed a promising performance for the electric/photo-to-thermal conversion applications. The highly thermal/electrical conductive PCMs composites were employed as an underfloor heating system in a test-room. Applying a small voltage (3 V) to the composites as a green heater led to a homogeneous indoor temperature increment. Owing to release of the high latent heat energy of the encapsulated PCMs, the indoor temperature kept at in the comfortable condition for a prolonged time without electricity consumption in energy peak load. Furthermore, the presence of metallic filler in the black composites led to high photo-to-thermal efficiency (up to 91 %) by irradiating with sunlight. In situ reduction of Ni nanoparticles in the pyrolysis process led to a graphitic carbon medium for PCMs to introduce a high performance composite in energy management application.