Dw Kim

Scalable Functionalized Graphene Nano-platelets as Tunable Cathodes for High-performance Lithium Rechargeable Batteries

High-performance and cost-effective rechargeable batteries are key to the success of electric vehicles and large-scale energy storage systems. Extensive research has focused on the development of (i) new high-energy electrodes that can store more lithium or (ii) high-power nano-structured electrodes hybridized with carbonaceous materials. However, the current status of lithium batteries based on redox reactions of heavy transition metals still remains far below the demands required for the proposed applications. Herein, we present a novel approach using tunable functional groups on graphene nano-platelets as redox centers. The electrode can deliver high capacity of ~250 mAh g−1, power of ~20 kW kg−1 in an acceptable cathode voltage range, and provide excellent cyclability up to thousands of repeated charge/discharge cycles. The simple, mass-scalable synthetic route for the functionalized graphene nano-platelets proposed in this work suggests that the graphene cathode can be a promising new class of electrode.

Rapid, High‐Resolution 3D Interference Printing of Multilevel Ultralong Nanochannel Arrays for High‐Throughput Nanofluidic Transport

3D interference printing enables the single-step production of multilayered ultralong nanochannel arrays with nanoscale regularity. The superior depth-of-focus of this technique realizes a state-of-the-art nanostructure which has intensively stacked 32 layers of inch-long, horizonontal nanochannels with sub-100 nm holes in a monolithic matrix (≈15 μm). This exceptional structure can be integrated into microfluidic devices, facilitating high-flux rheological platforms using nanocapillarity.

Effect of physicochemical microstructure on the thermal stability of ethylene-vinyl chloride copolymer

Abstract In this study, we investigated the relationship between the thermal stability and physicochemical microstructure of EV (ethylene-vinyl chloride) copolymer prepared by reductive dechlorination of PVC with tributyltin hydride. The EV copolymer grades varied in both molecular weight and ethylene content, the latter being in the range of 21–61 mol% ethylene. The thermal stability of EV copolymer was studied by thermogravimetic analysis (TGA). It was found that the rate of dehydrochlorination decreased with increase in degree of alternation of comonomer units in the copolymer and the homogeneity of its physical morphology. This study appears to substantiate the explanation put forward by Braun et al. and Naqvi for the thermal stability of this copolymer.