A novel in-situ assembly strategy has been developed to synthesis polyethylene glycol (PEG)@ iron-benze netricarboxylate metal-organic gel (MOG-100-Fe) shape-stabilized composite phase change materials by regulating metal-to-ligand ratio. The PEG@ MOG-100-Fe was prepared by an ingenious introduction of PEG into the traditional sol-gel prepared MOG-100-Fe. The composite exhibited high heat storage density and thermal stability. The PEG loading content reached up to 92% without any leakage above its melting point. The heat storage density reaches to 152.88 kJ kg (1) and is up to 95.8% of their theoretical value. These novel composite PCMs also exhibited excellent recyclability after 50 thermal cycles. (C) 2017 Published by Elsevier B. V.