Self-Assembly CNTs@PANi Coffee Rings on Poly(styrene-ethylene-butylene-styrene) Triblock Copolymer for Largely Stretchable Electronics

In this paper, CNTs@PANi nanocomposites were prepared by in-situ oxidation polymerization of aniline, and their structure, morphology and conductivity were characterized. A mixed solvent of toluene and tetrahydrofuran was used to prepare dispersions of CNTs@PANi and poly(styrene-ethylene-butylene-styrene) (SEBS) triblock copolymer, and bilayer composite film was prepared. According to the solvent phase separation and uneven evaporation flux, CNTs@PANi self-assembled into the interconnected coffee ring structure on the SEBS matrix. The prepared bilayer composite film had excellent stretchability, and the conductivity of the functional layer was close to that of CNTs@PANi, which could light up an LED lamp under 100% strain and restore the topological structure. Electrochemical tests showed that the bilayer film had obvious heterogeneity. The impedance characteristics of the CNTs@PANi functional layer and the SEBS matrix were analyzed, and its heterogeneous corrosion resistance mechanism further discussed.

Flexible all-solid-state supercapacitors of polyaniline nanowire arrays deposited on electrospun carbon nanofibers decorated with MOFs

Porous carbons derived from metal-organic frameworks (MOFs) are promising materials for a number of energy- and environment-related applications. To integrate the powder MOFs-derived carbon into feasible engineered materials, a facile strategy to fabricate integrated flexible film is developed by growing MOFs nanoparticles on polyimide electrospun nanofibers, followed by calcination, to fabricate freestanding carbon nanofiber membranes decorated with porous carbon. Then vertically polyaniline nanowire arrays are uniformly deposited on the hierarchical porous carbon substrates by in situ polymerization. Thanks to the good distribution of MOFs-derived porous carbon on carbon nanofibers and the compact configuration interwoven by conducting polymers, the designed hybrid electrode could be used directly as a freestanding electrode for supercapacitors, which displayed a high specific capacitance of 1268 F g^-1. The assembled flexible solid-state supercapacitor based on the integrated electrodes demonstrated a high volumetric capacitance of 1973 mF cm^-3 and a good capacitance retention of 84.9% after 10 000 cycles, which could power a commercial light emitting diode. This strategy may shed light on the design of MOFs-based flexible materials for practical applications of supercapacitors and other electrochemical devices.

Facile Processing of Free-Standing Polyaniline/SWCNT Film as an Integrated Electrode for Flexible Supercapacitor Application

Flexible supercapacitors (SCs) with compact configuration are ideal energy storage devices for portable electronics, owing to their original advantages (e.g., fast charging/discharging). To effectively reduce the volume of SCs, an integrated electrode of free-standing polyaniline (PANI)/single-wall carbon nanotube (SWCNT) film with high performance has been developed via a facile solution deposition method, which can be employed as current collector and active material in the meantime. Thanks to the strong π-π interactions between PANI and CNTs, an efficient conductive network with ordered PANI molecular chains is formed in this hybrid film electrode, which is beneficial for the ion diffusion process and fast redox reaction resulting in a high capacitance of 446 F g^-1 and outstanding cycling stability, achieving 98% retention over 13 000 cycles. Predictably, solid-state SCs constructed by this free-standing PANI/SWCNT film electrode exhibited remarkable mechanical stability and flexibility in a compact configuration, let alone its excellent capacitive performance (218 F g^-1). Moreover, the highest energy density of flexible solid-state SC reached 19.45 Wh kg^-1 at a power density of 320.5 W kg^-1, further indicating a good potential as an energy storage device. This work would inspire other simple process techniques for high-performance flexible SCs, catering to the demand of portable electronic devices.