Synergy of polypyrrole and carbon x-aerogel in lithium-oxygen batteries.

A crucial step in the development of lithium-oxygen (Li-O) batteries is to design an oxygen cathode with high catalytic activity and stable porous structure. Achieving such design requires an integrated strategy in which porosity, conductivity, catalytic activity, and mechanical durability are all considered in a battery system. Here, we develop polypyrrole-coated carbon x-aerogels with macroscopic 3D architecture, and demonstrate their potential as oxygen cathodes for Li-O batteries.

Effects of morphology and chemical doping on electrochemical properties of metal hydroxides in pseudocapacitors.

It is well known that both the structural morphology and chemical doping are important factors that affect the properties of metal hydroxide materials in electrochemical energy storage devices. In this work, an effective method to tailor the morphology and chemical doping of metal hydroxides is developed. It is shown that the morphology and the degree of crystallinity of Ni(OH)2 can be changed by adding glucose in the ethanol-mediated solvothermal synthesis.

Highly efficient oxygen reduction electrocatalysts based on winged carbon nanotubes.

Developing electrocatalysts with both high selectivity and efficiency for the oxygen reduction reaction (ORR) is critical for several applications including fuel cells and metal-air batteries. In this work we developed high performance electrocatalysts based on unique winged carbon nanotubes. We found that the outer-walls of a special type of carbon nanotubes/nanofibers, when selectively oxidized, unzipped and exfoliated, form graphene wings strongly attached to the inner tubes.

Flexible asymmetric supercapacitors with high energy and high power density in aqueous electrolytes.

Supercapacitors with both high energy and high power densities are critical for many practical applications. In this paper, we discuss the design and demonstrate the fabrication of flexible asymmetric supercapacitors based on nanocomposite electrodes of MnO(2), activated carbon, carbon nanotubes and graphene. The combined unique properties of each of these components enable highly flexible and mechanically strong films that can serve as electrodes directly without using any current collectors or binders.

Synergistic effects from graphene and carbon nanotubes enable flexible and robust electrodes for high-performance supercapacitors.

Flexible and lightweight energy storage systems have received tremendous interest recently due to their potential applications in wearable electronics, roll-up displays, and other devices. To manufacture such systems, flexible electrodes with desired mechanical and electrochemical properties are critical. Herein we present a novel method to fabricate conductive, highly flexible, and robust film supercapacitor electrodes based on graphene/MnO(2)/CNTs nanocomposites.