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From anisotropic graphene aerogels to electron- and photo-driven phase change composites

Li, Guangyong, Zhang, Xuetong, Wang, Jin, Fang, Jianhui
Journal of materials chemistry A 2016 v.4 no.43 pp. 17042-17049
aerogels, anisotropy, annealing, chemical reduction, crystallization, drying, durability, electric potential difference, graphene, graphene oxide, hydrochloric acid, liquid crystals, solar radiation, thermal conductivity
To overcome fatal shortcomings of organic phase change materials (PCMs), such as leakage during work, low thermal conductivity and shortage of multiple driving ways, we propose a novel strategy to synthesize structurally, mechanically, electrically and optically anisotropic graphene aerogels (AN-GAs) by using gaseous hydrogen chloride to in situ solidify ordered graphene oxide liquid crystals followed by chemical reduction, supercritical fluid drying and annealing in an Ar atmosphere in sequence. The confined pore space and aligned wall structure of the resulting AN-GAs have benefited crystallization of organic phase change molecules and thus highly efficient phase change composites (PCCs) are fabricated with long durability and good strength. The resulting PCCs can also be driven either by applying a small voltage (1–3 V) with high electro-heat efficiency (up to 85%) or by irradiating with weak sunlight (0.8–1.0 sun) with high photo-heat efficiency (up to 77%).