Effect of graphene oxide aerogel on dehydration temperature of graphene oxide aerogel stabilized MgCl_2·6H_2O composites

摘要

Thermochemical heat storage is an efficient energy storage technology to settle the problem in solar energy applications. In this paper, graphene oxide aerogel (GOA) stabilized MgCl2 center dot 6H(2)O composites with varying MgCl2 center dot 6H(2)O contents are prepared by typical hydrothermal and freeze drying methods. The effect of GOA on dehydration temperature of GOA-MgCl2 center dot 6H(2)O composites is investigated using differential scanning calorimetry (DSC). Due to nanosize effect and low crystallinity of MgCl(2 center dot)6H(2)O on the inner surface of GOA based on the observation of XRD and TEM, main corresponding dehydration peaks of the curves move to lower temperature with the increase of GOA content in the composites. Compared with pure MgCl2 center dot 6H(2)O, the fourth endothermic peak temperature of the composites containing 50 wt% MgCl2 center dot 6H(2)O decreases by 90 degrees C. Till now, it is the first time that a new approach to manipulate the dehydration temperature of salt hydrates is reported. Meanwhile, the highest loading rate of MgCl2 center dot 6H(2)O reaches 90 wt%, at which energy density of the composites is accordingly as high as 1598 J/g. Thus GOA stabilized MgCl2 center dot 6H(2)O composites will play an important role in the field of low temperature thermochemical heat storage.