Nanoengineering of MgSO4 nanohybrid on MXene substrate for efficient thermochemical heat storage material

Abstract

2D MXene nanohybrid is a next-generationenergy-storage material. Here, we demonstrate a novel thermochemical heat storage material using magnesium sulfate heptahydrate/titanium carbide and MXene (MgSO4/Ti3C2Tx) with improved hydration/dehydration enthalpy, superior thermal conductivity, good cyclic ability, maximum water sorption performance, and larger thermal energy conversion. The TG-DSC fitted with a Wetsys flow humidity generator shows outstanding thermal performance and larger hydration for MgSO4/Ti3C2Tx (1963 J/g) and dehydration (1861 J/g) enthalpies with 5 % fluctuation as compared to pure MgSO4 (38 %). The cyclicability results showed that MgSO4/MXene has good stability of TCMs across several charging/discharging cycles (up to 20 cycles), confirming that the MXene matrix avoids hydrated salt agglomeration and displays an average of 12 % fluctuation. This illustrates that prepared composites potentially improve storage performance. The MgSO4/Ti3C2Tx nanohybrid exhibit a better radiation absorption and 45 % longer backup than the pristine MgSO4 salt. TEM study revealedthat maximum salt contents can be located in the interlayer gaps, predicted sheets thickness of the MgSO4/MXene layer to be 16 Åand the Ti3C2Tx layers to be 7.3 Å. Nanohybrid has stronger water sorption than MgSO4 due to MXene nanosheets larger interlayer gaps. The results conclude that the resultant MgSO4/MXene has excellent long-term thermal energy storage, photo-to-thermal conversion and larger water sorption performance. The study validates the effectiveness of nanohybrid material as a promising candidate for thermochemical heat storage applications and set to pave the way to explore other hybrid systems to improve the efficiency of thermochemical energy storage systems.