Doo Seong Choi

Rechargeable Organic Radical Battery with Electrospun, Fibrous Membrane-Based Polymer Electrolyte

An organic radical battery (ORB) operating at room temperature with lithium metal anode and radical polymer poly(2,2,6,6-tetramethylpiperidinyloxy-4-ylmethacrylate) (PTMA) cathode with a microporous polymer electrolyte based on electrospun poly(vinylidene fluoride-co-hexafluoropropylene) membrane has been demonstrated. The polymer electrolyte with a fully interconnected pore structure, high electrolyte uptake, and high ionic conductivity is found to be suitable for use in PTMA-based ORBs. The cell with a thin cathode of 17 μm thickness incorporating 40 wt % of PTMA exhibits a discharge capacity of 111 mAh/g at 1 C-rate (0.1 mA/cm 2 ) that corresponds to ∼ 100% theoretical capacity. Good rate capability is shown by the ORB; thus, a specific capacity of 98 mAh/g is delivered even at the very high 50 C-rate. A stable cycle property is obtained at all C-rates, with the cathode structure remaining intact during cycling. The polymer electrolyte shows good compatibility with the electrodes and leads to a decrease of electrode/electrolyte interfacial resistance with cycling. The study indicates the suitability of microporous, polymer electrolyte-based ORB as a safe, lightweight, environmentally benign, flexible battery with high power-rate capability for varied applications.

Thermodynamically- and kinetically-controlled Friedel–Crafts alkenylation of arenes with alkynes using an acidic fluoroantimonate(V) ionic liquid as catalyst

By employing superacidic fluoroantimonate ionic liquid (IL), [bmim][Sb(2)F(11)], as catalyst, not only thermodynamically-controlled but also kinetically-controlled Friedel-Crafts alkenylations of arenes with alkynes have been realized for the first time.

The dramatic acceleration effect of imidazolium ionic liquids on electron transfer reactions

Imidazolium ionic liquids (ILs) exhibited a dramatic acceleration effect on the electron transfer from metal complexes such as (C(5)Me(5))(2)Fe(II) and (C(5)Me(5))(2)Co(II) to the oxygen molecule; this acceleration effect can be ascribed to the stabilization of the oxygen radical anions by coordinating with the acidic C2-H of imidazolium ILs.