Flexible Fiber Electrodes with Dual Functions: Supercapacitor and Electrochromism

이승민,김성곤 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.1

Functional smart energy storage is attracting great interest in the demand of being miniscule, thin, lightweight, flexible, and even rollup. The large surface area of electrodes is important for supercapacitors because it provides electrical double layer that can store energy. Electrochromic electrodes can reversibly change their colors obviously according to their redox states. Here we report the microfiber electrodes that function for supercapacitor and electrochromism. Fiber electrodes show supercapactive and electrochromic behaviors and are significantly promising for the application of future energy storage. Tungsten trioxide (WO₃) nanofibers are deposited on the surface of Ag nanowirecoated polymer fiber. The capacitive and electrochromic properties of this electrodes are demonstrated by performing physical and electrochemical characterization.

An electrochromically-driven photonic skin based on highly deformable iontronic polymer pump

구제형,( Amoli Vipin ),김소영,김도환 한국공업화학회 2019 한국공업화학회 연구논문 초록집 Vol.2019 No.0

Photonic skin is a sensory device system that can directly reflect external stimuli by generating visual human-readable response through optical means such as light emitting or chromism. Electrochromism is the phenomenon that color of semiconducting materials is reversibly changed by electrochemical redox reaction. In this work, we report the first electrochemically-driven photonic skin based on highly deformable iontronic polymer pump. Ionic thermoplastic polyurethane film with ionic liquid ([EMIM⁺][TFSI^-]) prepared under an optimal condition, as a role of functional elastomeric ion pumps, could serve good mechanical properties, high transmittance, and ionic conductivity. In addition, we could selectively migrate ions into the chromic material with a conductive pen under low voltage. This allows us to expect that our iontronic, photonic skin can be applicable to active touch board for directly visualized writing and erasing, reversibly for next generation human-machine soft interface.

Electrochromic titania nanotube arrays for the enhanced photocatalytic degradation of phenol and pharmaceutical compounds

Zheng, Qing,Lee, Hye-Jin,Lee, Jaesang,Choi, Wonyong,Park, Noh-Back,Lee, Changha Elsevier 2014 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.249 No.-

<P><B>Abstract</B></P> <P>Vertically aligned, electrochromic-coloured, amorphous titania nanotube arrays (TNAs) were fabricated using a facile room-temperature, solution-based electrochemical cathodisation method. Rapid cathodisation within 30s converted pristine TNAs into their dark analogues. Compared to their untreated counterparts, the cathodised dark TNAs exhibited significantly enhanced optical absorbance, covering the full spectrum of visible light. Further annealing of the electrochromic coloured amorphous TNAs in a N<SUB>2</SUB> atmosphere induced their transformation into dark crystalline TNAs, which directly harnessed simulated sunlight for the photocatalytic degradation of organic contaminants, including phenol, ibuprofen, carbamazepine and caffeine. Compared to the pristine crystalline TNAs (annealed in air), the dark crystalline TNAs showed higher optical absorbance, larger charge carrier density, lower electron transport resistance, and an enhancement of 107−131% in degradation kinetics for the target organic contaminants.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Electrochromic titania nanotube arrays were fabricated by a cathodisation method. </LI> <LI> The fabricated materials exhibited enhanced photo- and electrochemical properties. </LI> <LI> The fabricated materials showed enhanced photocatalytic degradation of organics. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>

Mesoporous Ni-PANI composite electrode for electrochromic energy storage applications

Inamdar, Akbar I.,Chavan, Harish S.,Kim, Hyungsang,Im, Hyunsik Elsevier 2019 Solar energy materials and solar cells Vol.201 No.-

<P><B>Abstract</B></P> <P>Nanostructured mesoporous Ni-PANI thin film electrodes are fabricated on indium-doped tin oxide (ITO) conducting glass substrates using a pulse potential electro-polymerization technique. The Ni-PANI film is amorphous in nature and exhibits a mesoporous cauliflower like morphology. The multifunctional characteristics of Ni-PANI as an electrode for a smart supercapacitor are investigated using electrochemical and optical techniques in 0.5 M LiClO<SUB>4</SUB> +PC electrolyte. It is dark blue when it is charged at 0.7 V (vs SCE), and it is transparent when it is discharged at −0.7 V (vs SCE). Moreover, it can exhibit other colours like sky blue and parrot green in intermediate states. Specific discharge capacitance of 543 Fg<SUP>−1</SUP> and 267 Fg<SUP>−1</SUP> at a current density of 1 Ag<SUP>−1</SUP> is obtained for Ni-PANI and pure PANI respectively. The observed colouration efficiency is 45.9 cm<SUP>2</SUP>C<SUP>−1</SUP> for Ni-PANI and 35.1 cm<SUP>2</SUP>C<SUP>−1</SUP> for pure PANI at a wavelength of 630 nm. An outstanding optical modulation of 55.6% with a capacity retention of 90% after 5000 cycles is obtained for Ni-PANI electrode. The robust synthesis of Ni-PANI electrodes with efficient smart supercapacitor activity can be used as alternative materials in smart energy storage devices.</P> <P><B>Highlights</B></P> <P> <UL> <LI> The NiO<SUB>x</SUB>-PANI exhibited multifunctional activity as energy storage and electrochromism. </LI> <LI> It is capable of sensing colour with respect to the level of energy stored. </LI> <LI> The device exhibits a colouration efficiency of 45.9 cm<SUP>2</SUP>C<SUP>-1</SUP> with an optical modulation of 55.6%. </LI> <LI> The high specific capacity is 543 F g<SUP>−1</SUP>, with a large potential window of 1.3 V. </LI> </UL> </P>

파이센 이온젤 기반 단일층 전기변색 소자의 변색 특성에 대한 연구

김남현,박종승 한국섬유공학회 2020 한국섬유공학회지 Vol.57 No.2

Electrochromism is a phenomenon in which the color of an electroactive material changes when a voltage is applied. Polyaromatic hydrocarbons (PAHs) are colorless in the neutral state owing to their broad bandgap; however, under the applied voltage, they exhibit various colors during oxidation or reduction owing to the molecular plasma resonance phenomena. Among PAH materials, picene is an intriguing material, which has not been employed as an electrochromic material because of its high stability with a bandgap of more than 3 eV. In this study, the electrochromic performance of a picene-containing ion gel consisting of poly(vinylidene-co-hexafluoropropylene) and imidazole-based ionic liquid (IL) was investigated. In an electrochromic device (ECD) fabricated on indium tin oxide (ITO) glass, the picene ECD was colorless in the neutral state; in the oxidation and reduction states, it showed reversible changes to yellow with an absorption peak at 520 nm. As the IL content increased, the bandgap decreased, and the switching behavior improved slightly. To further enhance the electrochromic performance, silver nanowires (AgNWs) were applied to the ITO electrodes. Compared with pristine ITO, the AgNW-based electrode exhibited significant improvement in optical contrast. Silver fabrics were used to produce highly flexible textile-based ECDs, which showed vivid and reversible electrochromic transitions under an applied voltage.

전기화학 기반의 전기 변색 센서 연구 동향

서민지,Seo, Minjee 한국전기화학회 2022 한국전기화학회지 Vol.25 No.4

Along with the increasing need for point-of-care diagnostics, development of portable, user-friendly, as well as sensitive sensors have gained intensive attention. Among various strategies, electrochromic sensors, which are electrochemically operated colorimetric sensors, have been actively studied. With their ability to report the presence and concentration of analytes by optical signals, electrochromic sensors utilize the advantages of both electrochemical and colorimetric sensors, enabling the simplification of device composition as well as convenient interpretation of results. Up to date, electrochromic sensors have been applied for a wide range of analytes, and further developments such as the introduction of flexible platforms or self-powered systems have been reported, providing a path towards the development of wearable sensor devices. In this review, various types of electrochromic sensors, according to the main strategy in which the electrochemical signals are converted to colorimetric signals, are introduced.

Complementary electrochromic windows with conductive nano-composite thin films

김유나,김은경 한국물리학회 2008 Current Applied Physics Vol.8 No.6

All-solid-state electrochromic windows which have complementary color transition were assembled by employing poly(aniline-Nbutylsulfonate) s (PANBS), photo polymerizable electrolyte and poly(3,4-ethylenedioxythiophene) (PEDOT) in sequence. Each electrochromic layer thickness was controlled in nano-scale in order to balance charges between the electrodes generated from the electroactive layers. The electrochromic (EC) properties were characterized using cyclic voltammetry, chronocoulometry and UV–Vis spectroscopy. Absorbance change and coloration efficiency were dependant on charge density and an all solid state EC display based on an optimized thickness showed EC response at 2.4 V within 5 s with a stable memory effect. All-solid-state electrochromic windows which have complementary color transition were assembled by employing poly(aniline-Nbutylsulfonate) s (PANBS), photo polymerizable electrolyte and poly(3,4-ethylenedioxythiophene) (PEDOT) in sequence. Each electrochromic layer thickness was controlled in nano-scale in order to balance charges between the electrodes generated from the electroactive layers. The electrochromic (EC) properties were characterized using cyclic voltammetry, chronocoulometry and UV–Vis spectroscopy. Absorbance change and coloration efficiency were dependant on charge density and an all solid state EC display based on an optimized thickness showed EC response at 2.4 V within 5 s with a stable memory effect.

Electrochromic and photoconductive polymer nanoparticles

백제훈,김유나,오현진,김은경 한국물리학회 2009 Current Applied Physics Vol.9 No.11

Electrochromic (EC) and photoconductive nanoparticles coated with a conducting polymer, poly(1,4- bis(2-[3',4'-ethylenedioxy]thienyl)-2-methoxy-5-2'''-ethylethylhexyloxybenzene) (PBETH) were prepared. TiO2 nanoparticles were employed as a nanotemplate for the preparation of conducting polymer capsules. The PBETH capsules showed blue to red transition by the applied potential showing electrochromic behavior. Electrochromic contrast, coloration efficiency and response time of the EC electrodes coated with PBETH/TiO2 were significantly improved compared to the electrode coated with PBETH without TiO2. Having conductive polymer layer and photoactive TiO2 particles, the polymer capsules showed photocurrent generation when exposed to a UV light. Electrochromic (EC) and photoconductive nanoparticles coated with a conducting polymer, poly(1,4- bis(2-[3',4'-ethylenedioxy]thienyl)-2-methoxy-5-2'''-ethylethylhexyloxybenzene) (PBETH) were prepared. TiO2 nanoparticles were employed as a nanotemplate for the preparation of conducting polymer capsules. The PBETH capsules showed blue to red transition by the applied potential showing electrochromic behavior. Electrochromic contrast, coloration efficiency and response time of the EC electrodes coated with PBETH/TiO2 were significantly improved compared to the electrode coated with PBETH without TiO2. Having conductive polymer layer and photoactive TiO2 particles, the polymer capsules showed photocurrent generation when exposed to a UV light.

Black to transparent electrochromic capacitive window with highly capacitive PANI-graphene composite

조철현,한민수,김은경 한국공업화학회 2020 한국공업화학회 연구논문 초록집 Vol.2020 No.-

Black to transparent switching electrochromic polymers with high optical contrast are applied to smart window, smart glasses and displays. Here, we synthesized organic electrochromic polymer based on ProDOT(3,4-propylenedioxythiophene) unit using direct arylation method. As a counter electrode material, polyaniline (PANI), known to have excellent capacitive properties, was used. In addition, PANI-graphene composite was synthesized for higher capacitive properties. Our electrochromic capacitive window (ECW) was fabricated by electrochromic layer which has broad absorption at visible range and high transmittance change and highly capacitive layer. Also, due to the solution-processibility of the organic electrochromic polymer, these ECWs can be applicable for flexible electronics and industrial scale use.

Effects of Pre-reducing Sb-Doped SnO2 Electrodes in Viologen-Anchored TiO2 Nanostructure-Based Electrochromic Devices

조성목,아칠성,김태엽,송주희,류호준,천상훈,김주연,김용해,황치선 한국전자통신연구원 2016 ETRI Journal Vol.38 No.3

In this paper, we investigate the effects of pre-reducing Sb-doped SnO2 (ATO) electrodes in viologen-anchored TiO2 (VTO) nanostructure–based electrochromic devices. We find that by pre-reducing an ATO electrode, the operating voltage of a VTO nanostructure–based electrochromic device can be lowered; consequently, such a device can be operated more stably with less hysteresis. Further, we find that a pre-reduction of the ATO electrode does not affect the coloration efficiency of such a device. The aforementioned effects of a pre-reduction are attributed to the fact that a pre-reduced ATO electrode is more compatible with a VTO nanostructure–based electrochromic device than a non-pre-reduced ATO electrode, because of the initial oxidized state of the other electrode of the device, that is, a VTO nanostructure–based electrode. The oxidation state of a pre-reduced ATO electrode plays a very important role in the operation of a VTO nanostructure–based electrochromic device because it strongly influences charge movement during electrochromic switching.