Graphene, a single layer of carbon atoms bonded in a hexagonal lattice, is the thinnest, strongest, and stiffest known material and an excellent conductor of heat and electricity. However, these superior properties have yet to be realized for graphene-derived macroscopic structures such as graphene fibers. We report the fabrication of graphene fibers with high thermal and electrical conductivity and enhanced mechanical strength. The inner fiber structure consists of large-sized graphene sheets forming a highly ordered arrangement intercalated with small-sized graphene sheets filling the space and microvoids. The graphene fibers exhibit a submicrometer crystallite domain size through high-temperature treatment, achieving an enhanced thermal conductivity up to 1290 watts per meter per kelvin. The tensile strength of the graphene fiber reaches 1080 megapascals.

Uniform ZnO QDs with controllable sizes from 2 to 7 nm on graphene were synthesized. The ZnO QD/graphene nanocomposites show enhanced electrochemical properties as lithium ion battery anodes.

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.

The capture and sequestration of Iodine-129 (129 I), a long-lived byproduct of nuclear fission, is essential to the implementation of advanced nuclear fuel cycles and effective nuclear waste management. Current state-of-the-art technologies inherently require silver to bind iodine, e.g., silver-loaded silica aerogels or silver-loaded zeolite (AgZ), which are very expensive and an environmental concern. It is highly desirable to develop alternative cost-effective adsorbents for iodine capture and sequestration. Herein, we report graphene-based nanomaterials including graphene powder and graphene aerogel as novel iodine sorbents showing exceptional adsorption capability and kinetics. By measuring iodine sorption capacities and uptake rates in an I 2(g) saturated environment, graphene sorbents display impressive iodine sorption capacities with powdered samples achieving mass gains in excess of 85 mass%, and aerogels exceeding 100% mass gains. A direct correlation among specific surface area, defect concentration, and maximum sorption capacity has been established, and the sorption kinetics of the graphene for iodine capture was determined.