Department of Energy EngineeringIn part 1, porous carbon has been prepared in diverse synthetic methods and utilized for energy storage devices. We present carbon sphere (CS), a type of porous carbon, by carbonization of phenylenediamine-mellitic acid (PDA-MA) resin at high temperature annealing process. Sphere-shape PDA-MA resin is readily synthesized with the mixture of m-PDA and mellitic acid through hydrothermal condensation without additional reagents. We found that the CS from the resin has high porosity (575 m2/g) and a substantial nitrogen content (~7%). The CS was tested for anode of Li-ion battery and showed cycle retention of 274 mAh/g after 400 cycles. In addition, rate capability test of the CS revealed fast kinetics and 82% capability retention from 2C to 10C. Showing a chance for further improvement on coulombic efficiency by higher temperature carbonization, this research gave possibility for the CS in energy storage application.
In part 2, the performance of fiber-reinforced composites is governed not only by the nature of each individual component comprising the composite, but also by the interfacial properties between the fiber and the matrix. We present a novel layer-by-layer (LbL) assembly for the surface modification of glass fiber to enhance the interfacial properties between the glass fiber and epoxy matrix. Solution-processable graphene oxide (GO) and an aramid nanofiber (ANF) were employed as active components for the LbL assembly onto the glass fiber owing to their abundant functional groups and mechanical properties. We found that the interfacial properties of the glass fibers uniformly coated with GO and ANF multilayers, such as surface free energy and interfacial shear strength, were improved by 23.6% and 39.2%, respectively, compared with those of the bare glass fiber. In addition, the interfacial adhesion interactions between the glass fiber and epoxy matrix were highly tunable simply by changing the composition and the architecture of layers, taking the advantages of versatility of the LbL assembly.ope
