Controllable Synthesis,functional Assembly And Properties Of Porous Carbon-based Composite Phase Change Materials

Herein,the dissertation emphasized on the design and characterization of novel porous solid supporting materials for shape-stabilized composite phase change materials(PCMs)and employed in thermal energy storage and conversion applications.It covers a brief introduction on thermal energy storage materials,composite PCM preparation,porous supporting materials with special emphasis on N-doped and/or porous carbons derived from metal-organic frameworks,metal organic gels and commercially available raw materials including biomaterials as a sustainable source of porous matrixes synthesis.Furthermore,the literature part summarized the recent research progress of thermal energy storage materials based on organic PCMs with specific examples.N-doped carbons derived from both in-situ from MOF and post-synthesis mechanism from commercially available starting materials(melamine and glucose)revealed high mesopore proportions,large surface area and average pore volume,thus demonstrating high myristic acid-stearic acid eutectic mixture(MA-SA)loading.The outcomes showed that N-doped porous carbons obtained from in-situ(NPC)encapsulated up to 88%PCM content with an enthalpy of 164.3 J/g,which is 45.7%superior to that of post synthesis route derived N-doped carbon(MGC)supporting MA-SA.Moreover,the composite revealed enhanced thermal transport 117.6%and 74.6%than that of pure MA-SA and MGC-based composites,correspondingly.Composite PCMs used for light-to-thermal(photo-driven)energy conversion was prepared by polymerizing light-absorbing molecule with PCM and further introduced into NPC via a facile one-pot synthesis approach.The composite has been exhibited enhanced thermal conductivity up to 178.3%and photo-thermal capability of 72.1%as a result of the presence of light-absorbing organic dye in as-prepared materials.The storage efficiency/mass reached to 180.3 J/g due to the interaction of solid supporting materials with the hard segment that bonded with PCM results free movement in a certain degree during the phase change process.Similarly,porous carbon derived from commercially available cotton via Mg(OH)2 template was synthesized at different pyrolysis temperatures and introduced into 1-hexadecanol.The porous carbon exhibited high PCM loading capacity/latent heat improvement compare to the calculated value reached to 85%/107.9%,90%/109.4%and 88%/109.8%for the corresponding carbonization of 700,800 and 900?,respectively.In addition,the composite disclosed improved thermal transport,reliability and stability with the absence of leakage.The graphitic nature,the porosity and reversible hydrogen bonding occurred between the PCM and porous supports played a remarkable role in the improvement of thermal parameters.Furthermore,new shape stable PCMs were fabricated using paraffin as energy storage material and porous carbon obtained from the metal organic gel(cMOG)with the presence of boron nitride(BN)as supporting material.The composite revealed enhanced thermal conductivity in solid/liquid states.Similarly,the ternary composites exhibited excellent chemical compatibility and low supercooling phenomenon with high durability after 200 thermal cycles.All the as-prepared composite materials overcame the basic drawbacks of organic PCMs and expected to contribute a notable role in thermal management systems including household applications.