title: Advanced phase change composite by thermally annealed defect-free graphene for thermal energy storage.
abstract: Organic phase change materials (PCMs) have been utilized as latent heat energy storage and release media for effective thermal management. A major challenge exists for organic PCMs in which their low thermal conductivity leads to a slow transient temperature response and reduced heat transfer efficiency. In this work, 2D thermally annealed defect-free graphene sheets (GSs) can be obtained upon high temperature annealing in removing defects and oxygen functional groups. As a result of greatly reduced phonon scattering centers for thermal transport, the incorporation of ultralight weight and defect free graphene applied as nanoscale additives into a phase change composite (PCC) drastically improve thermal conductivity and meanwhile minimize the reduction of heat of fusion. A high thermal conductivity of the defect-free graphene-PCC can be achieved up to 3.55 W/(m K) at a 10 wt % graphene loading. This represents an enhancement of over 600% as compared to pristine graphene-PCC without annealing at a comparable loading, and a 16-fold enhancement than the pure PCM (1-octadecanol). The defect-free graphene-PCC displays rapid temperature response and superior heat transfer capability as compared to the pristine graphene-PCC or pure PCM, enabling transformational thermal energy storage and management.
authors.affiliation: Department of Mechanical, Aerospace and Nuclear Engineering and ‡Department of Electrical, Computer & Systems Engineering, Rensselaer Polytechnic Institute , 110 Eighth Street, Troy, New York 12180, United States.
authors.forename: Guoqing
authors.initials: G
authors.lastname: Xin
authors.forename: Hongtao
authors.initials: H
authors.lastname: Sun
authors.forename: Spencer Michael
authors.initials: SM
authors.lastname: Scott
authors.forename: Tiankai
authors.initials: T
authors.lastname: Yao
authors.forename: Fengyuan
authors.initials: F
authors.lastname: Lu
authors.forename: Dali
authors.initials: D
authors.lastname: Shao
authors.forename: Tao
authors.initials: T
authors.lastname: Hu
authors.forename: Gongkai
authors.initials: G
authors.lastname: Wang
authors.forename: Guang
authors.initials: G
authors.lastname: Ran
authors.forename: Jie
authors.initials: J
authors.lastname: Lian
keywords: graphene; phase change enthalpy; phase change materials; thermal conductivity; thermal energy storage