Preparation of Slightly Crumpled Aminated Graphene Nanosheets for Honeycomb-Like Flexible Graphene/PANI Composite Film Electrode with Enhanced Capacitive Performance in Solid-State Supercapacitors.

Slightly crumpled aminated graphene nanosheets were prepared via the mild surface modification of graphene oxide (GO) nanosheets with p-phenylenediamine at room temperature to inhibit the restacking of graphene but avoid cross-linking during the solvothermal or microwave-assisted treatments, and then the honeycomb-like flexible graphene/polyaniline (PANI) composite film electrode, PANI@rPGO, was developed by the facile vacuum filtration and reduction. Owing to the slightly crumpled PGO nanosheets with surface amino groups, the honeycomb-like PANI@rPGO composite film, with a well-defined dispersion of PANI nanorods in the graphene-based matrix and the hierarchically porous structure, possessed superior electrochemical performance as a robust electrode in flexible solid-state supercapacitors (SSCs). The symmetric SSCs based on the PANI@rPGO electrode possessed a high capacitance of 564.5 F/g and 2015.2 mF/cm2 at 0.5 A/g (2.2 mA/cm2), superior cyclic life with retentions of 104.2 and 78.5% after 2000 and 5000 cycles at 3 A/g, as well as excellent flexibility. The mild one-pot preparation and the superior electrochemical performance make the designed PANI@rPGO composite film electrode a potential candidate for high-performance flexible SSCs.

Hierarchically Porous SnO2 Nanoparticle-Anchored Polypyrrole Nanotubes as a High-Efficient Sulfur/Polysulfide Trap for High-Performance Lithium-Sulfur Batteries.

Conductive supports could improve the electrical conductivity of the electrode in lithium-sulfur (Li-S) batteries but suffer from the shuttle effect originated from the polysulfide dissolution, while the hydrophilic metal oxides could avoid the shuttle effect but with poor conductivity. Herein, a facile approach was developed to fabricate hierarchically porous tin oxide (SnO2) nanoparticle-anchored tubular polypyrrole (T-PPy) as a sulfur host, in order to integrate the advantages of conductive supports and metal oxides but overcome their shortcomings. In the unique structure, the T-PPy nanotubes acted as a conductive network to not only improve the electrical conductivity of cathodes but also accommodate the volume expansion of the sulfur cathode during cycling as well as relatively confine the polysulfide diffusion, while the SnO2 nanoparticles served as a high-efficient polysulfide trap to mitigate the shuttle effect due to the chemical bond between SnO2 and polysulfides. Moreover, the hierarchically porous structure and therefore large surface area of the proposed S/(T-PPy)@SnO2 cathode were favorable for the accommodation of sulfur and lithium sulfides. Consequently, S/(T-PPy)@SnO2 with 64.7% sulfur mass content exhibited excellent cyclic stability with a decay rate of only 0.05% per cycle along with 500 cycles at 1 C, rate capability of 383.7 mA h/g at 5 C, and Coulombic efficiency above 90%, outstanding among most of the reported PPy-based sulfur cathodes and PPy-based ternary sulfur cathodes.