Lingling Fan

Flexible polypyrrole/copper sulfide/bacterial cellulose nanofibrous composite membranes as supercapacitor electrodes

Polypyrrole (PPy) and copper sulfide (CuS) have been successfully deposited on bacterial cellulose (BC) membranes to prepare nanofibrous composite electrodes of PPy/CuS/BC for flexible supercapacitor applications. The introduction of CuS remarkably improves the specific capacitance and cycling stability of BC-based electrodes. The specific capacitance of the supercapacitors based on the PPy/CuS/BC electrodes can reach to about 580Fg-1 at a current density of 0.8mAcm-2 and can retain about 73% of their initial value after 300 cycles, while the PPy/BC-based device could retain only 21.7% after 300 cycles. This work provides a promising approach to fabricate cost-effective and flexible nanofibrous composite membranes for high-performance supercapacitor electrodes.

An all-solid-state yarn supercapacitor using cotton yarn electrodes coated with polypyrrole nanotubes

A novel all-solid-state yarn supercapacitor (YSC) has been fabricated by using the cotton yarns coated with polypyrrole (PPy) nanotubes. The interconnected network structure of PPy can increase the surface area as well as the electrode/electrolyte interface area, thus resulting in improved electrochemical performance. For the proposed YSC, a high areal-specific capacitance of 74.0mFcm-2 and a desirable energy density of 7.5μWhcm-2 are achieved. The flexibility of the YSC demonstrates that it is suitable for the integration as flexible power sources in wearable electronic textiles.

Polypyrrole-coated cotton fabrics used for removal of methylene blue from aqueous solution

Abstract PPy-coated cotton fabric was prepared in situ chemical polymerization using blends of anionic and cationic surfactants as soft template and investigated as adsorbent to remove dyes in the printing and dyeing wastewater. The PPy-coated fabric was characterized by scanning electronic microscopy and fourier transform infrared spectrum. It was found that the fiber and fabric surfaces were coated by PPy nanoparticles with diameters less than 100 nm which were quite loose and well formed as a three-dimensional network. Dye adsorption experiments demonstrated that the PPy-coated fabric could effectively remove MB dye and the decoloration capacity of MB solution could reach up to 95.6%. Factors influencing the adsorption of MB, e.g. ionic strength, solution pH, contact time, and adsorption mass, were systematically investigated. The adsorption capacity for MB dye increased gradually as its initial concentration increased. The batch experimental results suggested that the PPy-coated fabric could be used as an efficient sorbent to remove dyes in textile effluents.

Paper Electrodes Coated with Partially-Exfoliated Graphite and Polypyrrole for High-Performance Flexible Supercapacitors

Flexible paper electrodes for supercapacitors were prepared with partially-exfoliated graphite and polypyrrole as the active materials. Graphite was coated on paper with pencil drawing and then electrochemically exfoliated using the cyclic voltammetry (CV) technique to obtain the exfoliated graphite (EG)-coated paper (EG-paper). Polypyrrole (PPy) doped with β-naphthalene sulfonate anions was deposited on EG-paper through in-situ polymerization, leading to the formation of PPy-EG-paper. The as-prepared PPy-EG-paper showed a high electrical conductivity of 10.0 S·cm−1 and could be directly used as supercapacitor electrodes. The PPy-EG-paper electrodes gave a remarkably larger specific capacitance of 2148 F∙g−1 at a current density of 0.8 mA∙cm−2, compared to PPy-graphite-paper (848 F∙g−1). The capacitance value of PPy-EG-paper could be preserved by 80.4% after 1000 charge/discharge cycles. In addition, the PPy-EG-paper electrodes demonstrated a good rate capability and a high energy density of 110.3 Wh∙kg−1 at a power density of 121.9 W∙kg−1. This work will pave the way for the discovery of efficient paper-based electrode materials.