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Porous poly(3,4-ethylenedioxythiophene) (PEDOT) nanoarray used for flexible supercapacitor has been prepared to investigate its electrochemical capacitance performance. Well-aligned titania (TiO 2 ) and titanium nitride (TiN) nanotube array was fabricated by an anodization, crystallization, nitridation processes. PEDOT-TiO 2 and PEDOT-TiN nanoarray hybrid was fabricated by coating PEDOT on nanotube walls of TiO 2 and TiN through a pulse voltammetry electrodeposition process. PEDOT nanopore array was fabricated through HF corrosion of TiN from PEDOT-TiN. The morphology and microstructure of PEDOT-TiO 2 , PEDOT-TiN and PEDOT were characterized by scanning electron microscopy and Raman spectroscopy. The electrochemical capacitance was investigated by cyclic voltammetry and galvanostatic charge–discharge measurements. PEDOT-TiO 2 and PEDOT-TiN showed heterogeneous coaxial nanotube structure. PEDOT exhibited free-standing nanopore array structure. The specific capacitance of PEDOT-TiN nanoarray hybrid was determined to be 393.1 F g −1 at a current density of 1.0 mA cm −2 , presenting much higher capacitance than PEDOT-TiO 2 nanoarray hybrid (128.7 F g −1 ) and PEDOT nanopore array (109.3 F g −1 ). All-solid-state flexible supercapacitor was constructed using supple electrode of PEDOT-TiN nanoarray hybrid and polyvinyl alcohol gel electrolyte of sulphuric acid. The volume specific capacitance, energy and power density were determined to be 4.08 F cm −3 , 2.26 mW h cm −3 and 250 mW cm −3 at a high output voltage of 2.0 V and a current density of 10 mA cm −2 . PEDOT-TiN nanoarray hybrid exhibited the effective energy storage in flexible supercapacitor application. [ABSTRACT FROM AUTHOR]

The ternary nanocomposite of polyaniline/carbon/titanium nitride (PANI/C/TiN) nanowire array (NWA) is fabricated as electroactive electrode material for flexible supercapacitor application. Firstly, TiN NWA is formed through ammonia nitridation treatment of TiO 2 NWA, which is synthesized via seed-assisted hydrothermal reaction. PANI/C/TiN NWA is then formed through sequentially coating carbon and PANI on the surface of TiN NWA. PANI/C/TiN NWA has unique shell/shell/core architecture, including a core layer of TiN NWA with a diameter of 40–160 nm and a length of 1.5 μm, a middle shell layer of carbon with a thickness of about 6.0 nm and an external surface layer of PANI with a thickness of 20–50 nm. PANI/C/TiN NWA provides ion diffusion channel at interspaces between the neighboring nanowires and electron transfer route along independent nanowires. The carbon shell layer is able to protect TiN NWA from electrochemical corrosion during charge/discharge process. PANI/C/TiN NWA displays high specific capacitance of 1093 F g −1 at 1.0 Ag −1 , and good cycling stability with a capacity retention of 98% after 2000 cycles, presenting better supercapacitive performance than other integrated nanocomposites of C/PANI/TiN, PANI/TiN and PANI/C/TiO 2 NWA. Such a ternary nanocomposite of PANI/C/TiN NWA can be used as an electrode material of flexible supercapacitors. [ABSTRACT FROM AUTHOR]

Highlights: [•] PANI/TiN core–shell nanowire arrays were prepared for supercapacitor application. [•] TiN nanowire arrays contributed to high surface area and low resistance for PANI. [•] PANI/TiN core–shell nanowire arrays exhibited much higher capacitance than PANI/TiO2. [Copyright &y& Elsevier]