Facile assembly of cellulose-derived 3D-graphene/lithium hydroxide monohydrate nanocomposite for low-temperature chemical heat storage

摘要

Commonly used nanocarbon composite materials are routinely synthesized from petroleum-based resources. To avoid their bad impact on the environment, using cellulose-based materials as the promising resources is a better choice due to its easy acquisition and rich reserves. In this study, microcrystalline cellulose was selected as the carbon precursor to synthesize novel cellulose-derived 3D-graphene/LiOHH2O nanomaterials for chemical heat storage to improve the efficiency of thermal energy utilization. The characterization and performance test results show that LiOHH2O particles (5-20nm) were highly dispersed on the 3D graphene carbon skeleton. These materials had excellent heat storage densities and thermal conductivities due to a completely new, hydrophilic, nano-reactive interface on 3D graphene. Among the materials, 3D-GF-VC-LiOHH2O (Ascorbic acid-modified 3D-graphene/LiOHH2O) exhibited the best heat storage and thermal conductivity properties. It achieved a thermal conductivity of 2.6W/mK, which was 1.5 times that obtained with pure LiOHH2O, and its heat storage density (2157kJ/kg) was 3.3 times that of pure LiOHH2O (661kJ/kg). The activation energy could decrease to 27.5kJ/mol. Moreover, the heat storage temperature range of LiOHH2O was clearly expanded by introduction of 3D graphene. Hence, the addition of cellulose-derived 3D graphene is a very efficient means by which the design of chemical heat storage materials can be improved.