Jian-Gan Wang

Rational synthesis of MnO2/conducting polypyrrole@carbon nanofiber triaxial nano-cables for high-performance supercapacitors

This study presents a rational synthesis of hierarchical MnO2/conducting polypyrrole (PPy)@carbon nanofiber (CNF) triaxial nano-cables via in situ interfacial redox reaction. Uniform MnO2/PPy multifunctional nanocoatings (∼20 nm) are formed on individual electrospun CNFs, constructing a one-dimensional triaxial configuration. The unique architecture enables a maximum value of the MnO2/PPy pseudocapacitance and a strong synergetic effect of each component. The specific capacitance of the ternary nanocomposite as a freestanding electrode reaches as high as 705 F g−1 at 2 mV s−1. The three-dimensional porous electrode facilitates a large mass loading of active materials up to 2.0 mg cm−2, which leads to a high areal capacitance of 1.4 F cm−2. The improved electrical conductivity and strong structural integrity of the nanocomposite also endow the electrodes with good rate capability and long-term cycling stability. The superior electrochemical performance indicates that this method is an effective strategy for developing multifunctional nanocomposite electrodes for energy storage devices.

Nitrogen-enriched electrospun porous carbon nanofiber networks as high-performance free-standing electrode materials

Nitrogen-enriched porous carbon nanofiber networks (NPCNFs) were successfully prepared by using low-cost melamine and polyacrylonitrile as precursors via electrospinning followed by carbonization and NH3 treatments. The NPCNFs exhibited inter-connected nanofibrous morphology with a large specific surface area, well-developed microporous structure, relatively high-level nitrogen doping and great amount of pyridinic nitrogen. As free-standing new anode materials in lithium-ion batteries (LIBs), the NPCNFs showed ultrahigh capacity, good cycle performance and superior rate capability with a reversible capacity of as high as 1323 mA h g−1 at a current density of 50 mA g−1. These attractive characteristics make the NPCNFs materials very promising anode candidates for high-performance LIBs and, as free-standing electrode materials to be used in other energy conversion and storage devices.