Hybrid nanoparticle and salt-modified aluminum fumarate metal-organic framework for thermochemical adsorption heat storage

Thermochemical energy storage technology has been demonstrated to effectively address the challenges posed by the intermittent and volatile nature of renewable energy sources. This technology converts thermal energy into chemical energy through a chemical reaction. However, conventional adsorbents have shown suboptimal adsorption efficiency and inadequate thermal conductivity in thermochemical energy storage systems. This study proposes the use of an aluminum-based metal-organic framework as the solid adsorbent, with the initial product Al-Fum-Al 2 O 3 prepared by incorporating nano-Al 2 O 3 . The novel thermochemical energy storage material, LiCl@Al-Fum-Al 2 O 3 , was synthesized via the impregnation method. A systematic characterization of the material was conducted, encompassing its adsorption properties, thermophysical properties, adsorption-desorption kinetics, and stability. The addition of nano-Al 2 O 3 led to a significant improvement in the material's thermal conductivity. At a mass fraction of 13 wt% Al 2 O 3 , the composite exhibited a thermal conductivity of 0.21448 W·m −1 ·K −1 , which is 66 % higher than that of pure Al-Fum. Furthermore, encapsulating LiCl within the pore structure of Al-Fum-Al 2 O 3 led to a substantial enhancement in the thermochemical heat storage performance, with the heat of adsorption reaching 1185.22 kJ·kg −1 , representing an 85 % increase compared to the unmodified Al-Fum-Al 2 O 3 matrix. After completing 20 cycles of adsorption and desorption, the material demonstrated stable adsorption-desorption kinetics with minimal fluctuations in heat storage capacity. These findings underscore the promising potential of the synthesized aluminum-based MOF energy storage material for applications in thermochemical energy storage.