Polyaniline Arrays Research Articles

A “two cooking with one fish” strategy for modulating both polyaniline cathode and zinc anode towards enhanced kinetics and cycling stability for aqueous zinc ion batteries

The adverse stability of both polyaniline (PANI) and Zn anode remains a challenge to the long−term cyclability and rate capability of aqueous Zn−PANI batteries. Herein, a “two–cooking with one fish” strategy is presented to modulate both PANI cathode and Zn anode, in which nanoscale graphene sheets in cathode can promote ordered growth of PANI array, being conducive to provide large electrochemical active area and efficient transport pathways and alleviate volume variation during repeated charging/discharging process. Meanwhile, the honeycomb–like structure of graphene sheets as protective layer can accelerate zinc ion transport kinetics and suppress side reactions and zinc dendrite growth. Consequently, the optimized G/Zn symmetric cell delivers a remarkable lifespan over 1000 h at 1 mA cm−2 with 1 mAh cm−2. Furthermore, the assembled PANI/G/CC||G/Zn battery could deliver a specific capacity of 265.8 mAh g−1 at 0.2 A g−1, excellent rate capability (145.5 mAh g−1 at 20 A g−1), a maximum energy density of 246.9 W h kg−1 and power density of 8675.9 W kg−1, and especially capacity retention of 91.1 % after 10000 cycles. Combining with additional merits of low cost, eco–friendliness, and safe operation, our design will shed light on resolving the issues on cyclability and rate capability of aqueous Zn−PANI batteries.

Polyaniline nanoarrays grown on holey graphene constructed by frozen interfacial polymerization as binder−free and flexible gel electrode for high−performance supercapacitor

Compared with disordered structures, electrode materials with nanoarray structures can effectively improve the energy storage capacity of supercapacitors. Therefore, the construction of nanoarrays structures is an important research direction. Here, one kind of frozen interfacial polymerization was used to create a polyaniline (PANI) nanoarrays grown on holey graphene (HG). Long polyaniline nanoarrays were constructed with the promotion of ice crystal growth and the abundant pores of the HG. It is demonstrated that the formation of PANI array and hierarchical nanofiber structures is not only conducive to shorten charge transport, but also can effectively alleviate interfacial side reactions. Moreover, benefiting from the abundant active sites and hierarchical porous structure of the HG, highly oriented growth of PANI arrays, efficient charge diffusion and electrolyte infiltration can be achieved. As a result, specific capacitance, reversibility and cycling stability could be significantly improved. Especially, the PANI/HG−10 exhibited the maximum specific capacitance of 793.7 F g−1 at a current density of 1 A g−1. The all−solid−state flexible symmetric supercapacitor assembled by gel electrode possesses the energy density of 32.5 Wh kg–1 at a power density of 326.5 W kg–1, and maintained an excellent cycle retention approaching 90.5 % after 5000 cycles. This work expands the ideas for array structure construction and electrode fabrication.

Boosting hierarchical construction and charge storage capacity of polyaniline arrays grown on the surface of carbon cloth with the aid of graphene interlayer

To satisfy the demands of high areal energy density for wearable devices, a strategy was presented to design hierarchical structured polyaniline (PANI) arrays on the surface of carbon cloth as the composite textile electrodes for lightweight and flexible supercapacitors. Benefiting from the introducing of graphene interlayer as conductive buffer layer and biomass organic acids including succinic acid, citric acid, malic acid, and tartaric acid as the dopants, the oriented growth of dense PANI array with hierarchical structure were greatly promoted especially in the presence of tartaric acid. Unique array structures constructed on the thin graphene layer significantly increase the specific surface area of the electrode, and facilitate the ion transport and dissipate stress from repeated polymeric volume change, resulting in considerably enhanced areal capacitance, rate retention and structural stability for PANI composite textile electrodes. The all–solid–state supercapacitor assembled with redox gel electrolyte possesses a high areal capacitance of up to 2181 mF cm−2 at the current density of 5 mA cm−2, and delivers a maximum energy density of 302.9 μWh cm−2 at the power density of 1752.1 μW cm−2 with excellent cycling stability and bending ability, thus demonstrating its great potential applications for wearable electronics.

Three-dimensional porous AuNPs-decorated polyaniline array for ultrasensitive determination of trace Cd(II) and Pb(II) in drinking water

Herein, a three-dimensional porous nanomaterials AuNPs-decorated polyaniline nanowire arrays/carbon nanotube (Au-PANI-array@CNT) was constructed by modified dilute polymerization and redox reaction. The Au-PANI-array@CNT exhibited a larger specific surface area (50.03 m2 g−1) and abundant mesopores (average pore size: 19.6 nm), due to the vertical growth of PANI nanowire arrays on CNT. The Au-PANI-array@CNT composite with a three-dimensional interconnected porous structure exhibited abundant electroactive sites and high adsorption capacity, significantly enhancing the deposition and electrochemical reaction process of heavy metals. The AuNPs embedded on PANI nanowries can provide high catalytic activity and multidimensional electron transport channels, further improving the detection sensitivity. A sensing platform with ultra-high sensitivity (2091, 3890 μA μM−1 cm−2) and lower limit of detection (0.18, 0.15 nM) for Cd(II) and Pb(II) determination was developed based on the three-dimensional porous PANI composite. Furthermore, the sensing mechanism of Au-PANI-array@CNT with Cd(II) was explored by XPS and FTIR spectroscopy. The current response only decreased by 5% after being stored at room temperature for 2 months, indicating that the sensor has high reproducibility and stability. Finally, the analysis of drinking water samples verified the excellent practicability of the sensor for the simultaneous measurement of trace levels (nM) of Cd(II) and Pb(II).

Topographic Manipulation of Graphene Oxide by Polyaniline Nanocone Arrays Enables High‐Performance Solar‐Driven Water Evaporation

AbstractTuning the surface topography of solar evaporators is of significance for boosting light absorption and enhancing solar‐to‐vapor efficiency. Herein, a novel strategy to manipulate the surface topography of graphene oxide (GO) via electrostatic assembly coupled with in situ polymerizations of aniline is reported. The GO surface is fully hybridized with the polyaniline (PANI) nanocone arrays, manifesting periodic structures with highly foldable configurations. Additionally, the PANI arrays tune the surface chemistry of GO and retard the redispersion of GO into water, thus enabling corresponding composite (PG) robust structural durability. Featuring these intriguing attributes, when applied as an evaporator in pure water, the PG delivers an improved evaporation performance of 1.42 kg m−2h−1and a high evaporation efficiency of 96.6% under one sun illumination. Further investigations reveal that the periodically conical structures of PANI over GO surface strengthen light absorption via multiple reflections and facilitate heat localization. Desalination test substantiates the reliability of PG for practical freshwater production. The numerical simulations and optical microscopy observation exhibit the surface topography‐strengthened vapor generation effect. This study sheds new light on the rational manipulation of surface topography of photothermal materials for high‐efficiency solar evaporation.

Highly stable polyaniline array@ partially reduced graphene oxide hybrid fiber for high-performance flexible supercapacitors

The development of flexible supercapacitors (SCs) with high energy density, excellent deformation and cycling stability has great meaning for flexible electronic. Herein, polyaniline array@carbon nanotubes/partially reduced graphene oxide hybrid fiber (PANI@CNT/PRGO) was rationally designed and fabricated. The PANI array were vertically and uniformly grown on CNT/PRGO fiber by controlling the nucleation sites on the fiber. This unique structure enabled the ion to rapid diffusion and the electron to fast transport and sufficient utilization of active sites. The strong interfacial interaction between PANI and CNT/PRGO fiber can reduce the risk of PANI shedding from the fiber during mechanical deformation and long-term cycling. As a consequence, a fiber-shaped SC fabricated by PANI@CNT/PRGO fiber can deliver high volumetric capacitance of 50.2 F cm−3 at a current density of 60 mA cm−3 with 62.5% capacitance retention at 2000 mA cm−3. More encouragingly, the device not only possesses outstanding flexibility and deformation stability (Retention 96.6% after 2000 bending cycles) but also owns prominent long-term stability (Retention 95.8% after 20,000 cycles). Furthermore, the device can yield an outstanding energy density up to 6.97 mWh cm−3. This findings may carve out a new path for regulating the nucleation sites to control the distribution of nanomaterials on graphene fiber, thus obtain hybrid fiber electrodes with outstanding electrochemical performances.

Rational design of double perovskite La2Ni0.5Co0.5MnO6 decorated polyaniline array on MoO3 nanobelts with strong heterointerface boosting oxygen evolution reaction and urea oxidation

The design and implementation of affordable high-performance electrocatalysts for the oxygen evolution reaction (OER) and urea electrooxidation reaction (UOR) are critical for clean and environmentally friendly energy conversion. Herein, we constructed a novel heterostructure interface engineering of double perovskite La2Ni0.5Co0.5MnO6 (LNCM) nanoparticles and MoO3 nanobelt array-supported amorphous polyaniline (PANI; MoO3/P) for high-performance OER and UOR. Structural and morphological analyses confirmed the formation of a heterostructure interface. The optimized La2Ni0.5Co0.5MnO6@MoO3/P (LMP-30) demonstrated electrocatalytic performance with low overpotentials of 300 mV at 10 mA cm−2 (vs RHE) for OER and 0.48 V at 50 mA cm−2 (vs Hg/HgO) for UOR, as well as better stability after testing for 12 h. The improved electrocatalytic performance was attributed to its distinctive hierarchical nanostructure, which had a synergistic effect on modulating the electrical characteristics and an electrochemically active surface area. More importantly, the LNCM nanoparticles on the surface of MoO3/P nanobelts can potentially provide more electrocatalytic active sites, excellent charge transport capacity, enhanced electrical properties, and strong electronic contacts between MoO3/P and LNCM.

CuS/polyaniline nanoarray electrodes for application in high-performance flexible supercapacitors

It is imperative to design and fabricate a high-performance free-standing electrode to meet the demand for flexible energy-storage devices with the development of wearable and portable electronics. CuS is an impressive candidate as an ideal pseudo-capacitance material due to its high theoretical capacity, easy preparation and wide source of raw materials. However, the low conductivity of CuS limits its application. Herein, polyaniline (PANI) was coated on CuS @ functional carbon cloth (fCC) to address the inherent defects of CuS using a facile polymerization procedure. Nano-scale PANI arrays with excellent conductivity grown on super-hydrophilic fCC provide a superior electroactive surface and facilitate electron transfer and electrolyte diffusion, which enhance the electrochemical performance of free-standing electrode. The as-prepared PANI/CuS@fCC electrode exhibits outstanding areal capacitance of 2167.2 mF cm−2 at 0.5 mA cm−2, impressive capacitance retention rate (89.2 %) after 5000 cycles at 5 mA cm−2, and satisfactory mechanical properties and flexibility. The assembled symmetrical supercapacitor also exhibits significant rate capacity with a specific capacitance of 816.4 mF cm−2, a high energy density of 0.268 mW h cm−2 at 0.5 mW cm−2and stable cycle performance with a capacitance retention rate exceeding 98 %. This study provides an effective strategy to fabricate advanced and flexible supercapacitor electrode.

Sponge-Hosting Polyaniline Array Microstructures for Piezoresistive Sensors with a Wide Detection Range and High Sensitivity.

The development of highly elastic spongy conductors is attractive for use in piezoresistive sensors due to their low cost, easy fabrication, and wide sensing range. However, the combination of high sensitivity and broad sensing range in a single piezoresistive sensor, though highly demanded, is challenging because they are contradictory in principle. Herein, a highly elastic spongy conductor with sponge-hosting polyaniline (PANI) fluff-like array microstructures is fabricated through cryopolymerization. The as-obtained sponge-hosting conductors exhibited an excellent elasticity under high compression strain and stress of up to 80% and 101 kPa, respectively, covering typical deformation ranges for detecting complex human activities. Benefiting from the presence of the sponge-hosting fluff-like PANI arrays, the as-prepared sponge-hosting conductors for piezoresistive sensors possessed a high sensitivity of 0.54 kPa-1 in a broad pressure range of 0.1-101 kPa, ascribing to the formation of the sponge-hosting fluff arrays with graded conductive network structures of array contacts and sponge-skeleton contacts at low and high compressions, respectively. As a result, the as-assembled piezoresistive sensors were demonstrated for tactile sensing and human-motion monitoring. This work reveals new approaches for tailored fabrication of sponge-hosting conducting polymers with tunable fluff-like microstructures for highly sensitive and wide-range wearable piezoresistive sensors.

Highly Stable Polyaniline Array@ Partially Reduced Graphene Oxide Hybrid Fiber for High-Performance Flexible Supercapacitors

Highly Stable Polyaniline Array@ Partially Reduced Graphene Oxide Hybrid Fiber for High-Performance Flexible Supercapacitors

Constructing polyaniline nanowire arrays as efficient traps on graphene sheets to promote compound synergetic effect in the assembled coating for multifunctional protective cotton fabrics

Multifunctional protective coating with a novel trap structure containing Graphene oxide (GO) and Polyaniline (PANI) arrays is constructed on the surface of cotton fabrics through in–situ polymerization and spray assisted layer–by–layer assembly. The construction of nanoscale protective coatings with controllable thickness and different compounds on the surface of the cotton fabrics through spray assisted layer–by–layer assembly can better exert the molecular interaction between different layers and synergistic effect of different elements. More importantly, unique structure of PANI arrays are grown on the surface of the cotton fibers and GO sheets play very important role on the improvement of multifunctional performances for the cotton fabrics. PANI arrays can accept more APP molecules to promote the flame retardant behavior and construct nearly closed subspace to resist heat and oxygen, accompanying with the formation of inorganic barrier layer, excellent self–extinguishing ability can be achieved through nanoscale coating. Particularly, (GO–PANI1.0)3 coated cotton fabric with a weight gain of 12.7 wt% possesses the excellent self–extinguished ability and minimizes the total heat release value about 82.5% of pristine cotton. In addition, the PANI and GO reduced partially during in–situ polymerization of aniline can present good conductive pathway, as a result, the coated fabric also exhibits significant antistatic property, while can remarkably inhibit the growth of E. coli and S. aureus. Therefore this novel strategy with facile and scalable features can provide reference for developing various kinds of cheap composite nanocoating for multifunctional advanced textiles.

A sensitive and flexible sensor enhanced by constructing graphene-based polyaniline conductive networks

A sensitive and flexible sensor with dissimilar 3D conductive networks was fabricated by coating reduced graphene oxide (RGO) and polyaniline (PANI) on warp-knitted polyester-spandex fabric. In this study, the average length of 40∼80um 1D PANI rods or 2∼10um 1D PANI nanowires combined with 2D RGO sheet, forming 3D conductive networks. First the graphene oxide (GO) sheets was coated on the surface of fabric, then the GO was reduced to RGO, and the PANI array with ordered shapes was prepared on the surface of RGO fabric by self-assembled method and using sodium dodecyl benzene sulfonate (SDBS)/hydrochloric acid (HCl) or HCl as dopants. It could be found that the obtained 3D conductive network mainly presents two morphologies, one is nanorods-sheet shape (1:90 SDBS/HCl concentration ratio), and the other is nanowires-sheet shape (HCl 1 mol/L). The results show that the fabric with 3D nanorods-sheet conductive network exhibits outstanding conductivity (resistance = 0.228 KΩ/sq), strain sensitivity, wide strain sensing range (tolerable strain up to 100 %), and repeatability (withstand 500 stretching-releasing tests), precisely detecting human motion in flexible wearable devices.

Supercapacitors based on three-dimensional porous carbon/covalent-organic framework/polyaniline array composites

Supercapacitors based on three-dimensional porous kenaf stem-derived carbon (3D-KSC)/covalent-organic framework COF-LZU1 (COF-LZU-x series were synthesized and named by Lanzhou University, so it was named “LZU”)/polyaniline (PANI) array composites were fabricated. The spherical COF-LZU1 was formed by dehydration condensation reaction between 1,3,5-benzene tricarbaldehyde and 1,4-p-phenylenediamine and simultaneously bonded to the 3D-KSC surface, which improved the stability of composites. Then PANI array was grown on 3D-KSC/COF-LZU1 by chemical oxidation polymerization to form 3D-KSC/COF-LZU1/PANI composites. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), etc were used for characterizing 3D-KSC/COF-LZU1/PANI composites. SEM images showed that a lot of spherical COF-LZU1 with diameter of 1 µm was uniformly dispersed on the inner wall of the 3D-KSC, and PANI was arrayed on the 3D-KSC/COF-LZU1. FTIR and Raman spectroscopy proved that PANI arrays were successfully polymerized on 3D-KSC/COF-LZU1. Galvanostatic charge-discharge test of 3D-KSC/COF-LZU1/PANI composites showed a specific capacitance of 583.0 mF cm−2 at current density of 0.1 mA cm−2, and the specific capacitance was 81.5% of the original value after 2000 cycles. These results suggested the as-prepared 3D-KSC/COF-LZU1/PANI composites had excellent performance and the potential application in supercapacitors.

AuNPs-polyaniline nanosheet array on carbon nanofiber for the determination of As(III)

Abstract As(III) is a highly toxic and predominant arsenic species especially in anoxic groundwater. In this paper, the measurement of trace amount of As(III) was reported by using the Au-PANI-Fe-CNFs composite as sensing platform. The Au-PANI-Fe-CNFs composite was constructed by the formation of polyaniline (PANI) nanosheet array on the electrospun Fe-containing carbon nanofibers (Fe-CNFs) substrate followed by self-deposition of Au nanoparticle. PANI presents a uniform array structure on the fiber surface. Au nanoparticles were deposited uniformly on the PANI nanosheet surface by means of the reducing property of PANI, with the particle size of about 20 ± 6 nm. The presence of Fe in the CNFs accelerates the growth of PANI nanosheet and improves the As adsorption in the sensing process of As(III) thereafter. The obtained Au-PANI-Fe-CNFs exhibit excellent electrochemical performance for the detection of As(III) in water, because of the unique structure of PANI array and uniform distribution of AuNPs. The designed electrode displays wide linear range (5– 400 ppb) and high sensitivity with a detection limit of 0.5 ppb (S/N ≥ 3). This novel modified electrode shows a great opportunity for the electrochemical analysis of arsenic and its analogues in water.

In situ synthesis of hierarchical platinum nanosheets-polyaniline array on carbon cloth for electrochemical detection of ammonia

In this work, a self-supported electrode has been designed and fabricated based on carbon cloth-supported polyaniline array and Pt nanosheets (Pt-PANI-CC). PANI array was firstly loaded on the surface of CC via chronoamperometry technique, and then, Pt nanosheets were deposited on the per-grown PANI array through amperometric measurement. The hierarchical structure of Pt-PANI-CC electrode and unique sheet-like Pt nanoparticles offered large specific surface and response centers. The electrochemical sensor based on Pt-PANI-CC electrode has been successfully constructed for detection of ammonia. The experiment results demonstrated that Pt-PANI-CC displayed great catalytic activity for electro-oxidation of ammonia and exhibited acceptable performances for sensing ammonia with low detection limit of 77.2 nM and wide linear range from 0.5 μM to 550 μM. Moreover, the anti-interference ability, reusability, reproducibility and stability of sensor have been investigated and showed great performances. This work provides a promising way for designing self-supported sensing electrode toward a wide electrochemical detection.

Promoting Oriented Growth of a Polyaniline Array on Carbon Cloth through in Situ Chemical Polymerization under a High Voltage Electric Field for a Flexible Supercapacitor with High Areal Capacity and Stability

An effective approach for boosting oriented growth of polyaniline (PANI) arrays on carbon cloth (CC) is presented through spraying and in situ chemical polymerization under a high voltage electric ...

In-situ hybridization of graphene sheets onto polyaniline nanofiber arrays grown on the surface of carbon cloth under high electric voltage field for high–performance flexible supercapacitor

Two kinds of free–standing flexible hybrid electrode materials were fabricated through in situ hybridization of graphene oxides (GOs) onto polyaniline (PANI) nanofiber arrays grown on the surface of carbon cloth under high voltage electric field. The GOs introduced to the arrays could act as the growth sites or the top layer on the PANI arrays, depending on the spraying order of the GO before and after aniline. Great improvement in charge storage ability of PANI nanofibers could be achieved especially by using the GO as the substrate for the growth of the arrays. The PANI/GO/CC electrode showed a maximum areal capacitance of 1122.8 mF cm−2 at the scan rate of 5 mV s−1. Assembled with these electrodes, the all–solid–state symmetric supercapacitor could deliver a maximum energy density of 46.6 μWh cm−2 at a power density of 498.9 μW cm−2 with high capacitance retention of 94.1% and mechanical flexibility. The excellent capacitive performances could be ascribed to unique structural advantages of PANI nanofiber array enhanced by synergetic effect between PANI and graphene sheets. Such in situ hybridization could provide a facile and scalable route for fabricating high–performance free–standing flexible electrode materials for foldable and wearable devices.

Porous polyaniline arrays oriented on functionalized carbon cloth as binder-free electrode for flexible supercapacitors

Flexible supercapacitor (FSC), thanks to light weight, efficient power delivery and high safety, holds great potential in potable/wearable electronics, whose development would be accelerated by ideal electrode materials. Herein, we report a flexible binder-free electrode composed of polyaniline (PANI) nanofiber-lapped arrays in-situ grown on the molecular-modified carbon cloth (fCC) by a facile one-spot protocol. After optimization, PANI/fCC-2 electrode affords a high specific capacitance of 517.3 F g−1 at 1 A g−1, benefited from highly pseudocapacitive PANI and open channels favorable for rapid ion/electron transfer. Using this novel electrode, flexible quasi-solid-state SC with PVA/H2SO4 gel electrolyte displays a high energy density of 9.03 Wh kg−1 at a power density of 82.9 W kg−1 and is retained at 6.11 Wh kg−1 at 2784.3 W kg−1, with excellent rate capability (97.4% capacitance retention from 0.5 to 20 A g−1) and good cycling stability (79.5% retention over 10,000 cycles). Besides, such four devices in series can light up a light-emitting diode (LED) indicator as a proof of concept in real applications. Our research would provide a promising avenue to develop flexible integrated electrode for next-generation high-performance devices.

Field-Enhanced Nanoconvection Accelerated Electrocatalytic Conversion of Water Contaminants and Electricity Generation.

The development of high-performance electrocatalytic systems for the extraction of energy from contaminants in wastewater are urgently needed in emerging renewable energy technologies. However, given that most of the contaminants are present in low concentrations, the heterogeneous catalytic reactions often suffer from slow kinetics due to mass transfer limitations. Here, we report that localized free convection induced by enthalpy change of the reaction can enhance interfacial mass transport. This phenomenon can be found around high-curvature nanosized tips. The finite-element numerical simulation shows that the heat of reactions can produce temperature gradients and subsequently lead to fluid motion at the interfaces, which facilitates the rate-limiting step (mass transfer). To demonstrate the effects of localized field-enhanced mass transport in electrocatalytic conversion of aqueous dilute species, a galvanic cell is constructed with a vertically aligned polyaniline array with sharp tips (as cathode) for the detoxification of a low concentration of carcinogenic chromate and synchronous electricity generation, which show lower overpotential (0.17 V decreased), higher reaction rate (increased by 28%), and power density (22.3 W m-2 in 2 mM chromate). The power output can be scaled up (open voltage of ∼3.7 V and volumetric power density of 840.1 W m-3) by using a continuous flow-through cell with stacked electrodes for further improve the mass transport.

Three-dimensional kenaf stem-derived macroporous carbon/reduced graphene oxide/polyaniline integrated electrode for supercapacitors

Three-dimensional kenaf stem-derived macroporous carbon (3D-KSC)/reduced graphene oxide (rGO) integrated electrode were constructed as conductive support substrate to electrodeposit polyaniline (PANI) for building high-performance supercapacitors. Scanning electron microscopy (SEM), Raman spectroscopy, Fourier-transform infrared spectroscopy (FTIR) and electrochemical methods were used to characterize the 3D-KSCs/rGO/PANI electrode. It was found by SEM that lots of well-dispersed rGO uniformly grew on 3D-KSC based on covalent bond, which effectively avoided the aggregation of rGO on the electrode surface. FTIR and Raman spectroscopy confirmed that PANI arrays were polymerized on the 3D-KSCs/rGO surface vertically and uniformly. Constant current charging/discharging test was used to investigate the electrochemical properties of 3D-KSCs/rGO/PANI electrode. These test results showed that as-obtained 3D-KSCs/rGO/PANI supercapacitor electrode had gravimetric capacitance of 1224 mF g-1 at the current density of 0.3 A g−1, far larger than most other electrodes. In addition, the gravimetric capacitance remained 87% after 5000 charging/discharging cycles. The good performances of 3D-KSCs/rGO/PANI integrated electrode proved that the resulted supercapacitor electrode had wide prospect in energy storage application.