Preparation and characterization of metal organic framework based composite materials for thermochemical energy storage applications

Abstract

Using the chromium-based metal organic framework (MIL-101(Cr)) as a host matrix two composite materials were synthesized with Na2S2O3 (10 and 30% w/w) towards thermochemical energy storage (TCES) applications. The prepared composites were characterized using multiple techniques viz. Powder X-ray Diffractometer (PXRD), Dynamic Vapour Sorption (DVS) analyser and Thermogravimetric-Differential Scanning Calorimeter (TG-DSC), etc. The prepared composites were found to exhibit octahedral structures with salt in the pores. The MIL-101(Cr) with 30% Na2S2O3 (w/w) was estimated to yield a high energy storage density (1099.5 J/g) due to its high water vapour adsorption capacity. These composites were subjected to ten continuous adsorption and desorption processes using the DVS analyser to determine their stability for intended applications. The synthesized composites offered good water vapour adsorption capacity, energy storage density, and excellent stability with very little mass variations across the tested cycles. Based on the experimental results, the authors recommend the composite sorbents for TCES applications.

Keywords

• Thermochemical energy storage
• Metal organic frameworks
• Reaction enthalpy
• Water vapour adsorption capacity
• Stability