Preparation and characterization of aqueous polyaniline battery using a modified polyaniline electrode

Unveiling Organic Electrode Materials in Aqueous Zinc-Ion Batteries: From Structural Design to Electrochemical Performance

Aqueous zinc-ion batteries (AZIBs) are one of the most compelling alternatives of lithium-ion batteries due to their inherent safety and economics viability. In response to the growing demand for green and sustainable energy storage solutions, organic electrodes with the scalability from inexpensive starting materials and potential for biodegradation after use have become a prominent choice for AZIBs. Despite gratifying progresses of organic molecules with electrochemical performance in AZIBs, the research is still in infancy and hampered by certain issues due to the underlying complex electrochemistry. Strategies for designing organic electrode materials for AZIBs with high specific capacity and long cycling life are discussed in detail in this review. Specifically, we put emphasis on the unique electrochemistry of different redox-active structures to provide in-depth understanding of their working mechanisms. In addition, we highlight the importance of molecular size/dimension regarding their profound impact on electrochemical performances. Finally, challenges and perspectives are discussed from the developing point of view for future AZIBs. We hope to provide a valuable evaluation on organic electrode materials for AZIBs in our context and give inspiration for the rational design of high-performance AZIBs.

Synthesis and exceptional operational durability of polyaniline-inspired conductive ladder polymers

Ladder-type structures can impart exceptional stability to polymeric electronic materials. This article introduces a new class of conductive polymers featuring a fully ladder-type backbone. A judicious molecular design strategy enables the synthesis of a low-defect ladder polymer, which can be efficiently oxidized and acid-doped to achieve its conductive state. The structural elucidation of this polymer and the characterization of its open-shell nature are facilitated with the assistance of studies on small molecular models. An autonomous robotic system is used to optimize the conductivity of the polymer thin film, achieving over 7 mS cm-1. Impressively, this polymer demonstrates unparalleled stability in strong acid and under harsh UV-irradiation, significantly surpassing commercial benchmarks like PEDOT:PSS and polyaniline. Moreover, it displays superior durability across numerous redox cycles as the active material in an electrochromic device and as the pseudocapacitive material in a supercapacitor device. This work provides structural design guidance for durable conductive polymers for long-term device operation.

Electrochemical detection of white spot syndrome virus with a silicone rubber disposable electrode composed of graphene quantum dots and gold nanoparticle-embedded polyaniline nanowires

Background

With the enormous increment of globalization and global warming, it is expected that the number of newly evolved infectious diseases will continue to increase. To prevent damage due to these infections, the development of a diagnostic method for detecting a virus with high sensitivity in a short time is highly desired. In this study, we have developed a disposable electrode with high-sensitivity and accuracy to evaluate its performances for several target viruses.

Results

Conductive silicon rubber (CSR) was used to fabricate a disposable sensing matrix composed of nitrogen and sulfur-co-doped graphene quantum dots (N,S-GQDs) and a gold-polyaniline nanocomposite (AuNP-PAni). A specific anti-white spot syndrome virus (WSSV) antibody was conjugated to the surface of this nanocomposite, which was successfully applied for the detection of WSSV over a wide linear range of concentration from 1.45 × 10² to 1.45 × 10⁵ DNA copies/ml, with a detection limit as low as 48.4 DNA copies/ml.

Conclusion

The engineered sensor electrode can retain the detection activity up to 5 weeks, to confirm its long-term stability, required for disposable sensing applications. This is the first demonstration of the detection of WSSV by a nanofabricated sensing electrode with high sensitivity, selectivity, and stability, providing as a potential diagnostic tool to monitor WSSV in the aquaculture industry.

Organic Cathode Materials for Rechargeable Zinc Batteries: Mechanisms, Challenges, and Perspectives

Energy and environmental issues have given rise to the development of advanced energy-storage devices worldwide. Electrochemical energy technologies, such as rechargeable batteries, are considered to be the most reliable and efficient candidates. Compared with other batteries, zinc-based batteries seem promising due to their advantages, including inherent safety, cost-effectiveness, and environmentally friendliness. As potential alternatives to conventional inorganic cathodes, organic cathodes for Zn-organic batteries have become a hot topic for research, owing to their favorable characteristics, such as easy structure design, controllable synthesis, and environmental benignancy. Herein, a systematic overview on the fundamentals of organic cathode materials for zinc batteries, including material design, electrochemical mechanisms, technical advances, and challenging analysis, is provided. Furthermore, perspectives and corresponding research directions are offered to facilitate the future development of organic cathode materials for zinc batteries toward practical applications.

Preparation of magnetic core-shell Fe3O4@polyaniline composite material and its application in adsorption and removal of tetrabromobisphenol A and decabromodiphenyl ether

Present study described a magnetic adsorption and removal method with prepared magnetic core-shell Fe₃O₄@polyaniline microspheres for the removal of two typical BFRs, tetrabromobisphenol-A (TBBPA) and decabromodiphenyl ether (BDE-209) from water samples. Magnetic core-shell Fe₃O₄@polyaniline microspheres were prepared by a hydrothermal and two step polymerization method with cheap iron salts and aniline, which were characterized with transmission electron microscopic (TEM) and scanning electron microscopy (SEM). The results showed that the Fe₃O₄@polyaniline microspheres earned a clear thickness shell of polyaniline (about 50 nm) and a saturation magnetization of 40.4 emu g^-1. The Magnetic core-shell Fe₃O₄@polyaniline exhibited excellent adsorption capability and removal rate to TBBPA and BDE 209. The adsorption of TBBPA and BDE 209 all followed pseudo-second order kinetics and agreed well to the Freundlich adsorption isotherms model. The negative Gibbs free energy change (ΔG⁰) and positive standard enthalpy change (ΔH⁰) for TBBPA and BDE-209 suggested that the adsorption was spontaneous and endothermic in nature. These results demonstrated that Fe₃O₄@PANI was a good adsorbent and would have a good application prospect in the removal of pollutants from environmental water.

Dual-phase nanostructuring of layered metal oxides for high-performance aqueous rechargeable potassium ion microbatteries

Aqueous rechargeable microbatteries are promising on-chip micropower sources for a wide variety of miniaturized electronics. However, their development is plagued by state-of-the-art electrode materials due to low capacity and poor rate capability. Here we show that layered potassium vanadium oxides, K_xV₂O₅·nH₂O, have an amorphous/crystalline dual-phase nanostructure to show genuine potential as high-performance anode materials of aqueous rechargeable potassium-ion microbatteries. The dual-phase nanostructured K_xV₂O₅·nH₂O keeps large interlayer spacing while removing secondary-bound interlayer water to create sufficient channels and accommodation sites for hydrated potassium cations. This unique nanostructure facilitates accessibility/transport of guest hydrated potassium cations to significantly improve practical capacity and rate performance of the constituent K_xV₂O₅·nH₂O. The potassium-ion microbatteries with K_xV₂O₅·nH₂O anode and K_xMnO₂·nH₂O cathode constructed on interdigital-patterned nanoporous metal current microcollectors exhibit ultrahigh energy density of 103 mWh cm⁻³ at electrical power comparable to carbon-based microsupercapacitors.

Aqueous rechargeable microbatteries could enable new microelectronics, but their current electrode materials still suffer from low capacity and poor rate capability. Here the authors show that layered K_xV₂O₅·nH₂O with an amorphous/crystalline dual-phase nanostructure can address these issues.

Recent Progress in Multivalent Metal (Mg, Zn, Ca, and Al) and Metal-Ion Rechargeable Batteries with Organic Materials as Promising Electrodes

The emerging demand for electronic and transportation technologies has driven the development of rechargeable batteries with enhanced capacity storage. Especially, multivalent metal (Mg, Zn, Ca, and Al) and metal-ion batteries have recently attracted considerable interests as promising substitutes for future large-scale energy storage devices, due to their natural abundance and multielectron redox capability. These metals are compatible with nonflammable aqueous electrolytes and are less reactive when exposed in ambient atmosphere as compared with Li metals, hence enabling potential safer battery systems. Luckily, green and sustainable organic compounds could be designed and tailored as universal host materials to accommodate multivalent metal ions. Considering these advantages, effective approaches toward achieving organic multivalent metal and metal-ion rechargeable batteries are highlighted in this Review. Moreover, organic structures, cell configurations, and key relevant electrochemical parameters are presented. Hopefully, this Review will provide a fundamental guidance for future development of organic-based multivalent metal and metal-ion rechargeable batteries.

Nitrite-Enhanced Charge Transfer to and from Single Polyaniline Nanotubes

As Liu et al. reported previously (Appl. Mater. Today 2017, 7, 239-245), the charge transfer to partially oxidized polyaniline (PANI) nanotubes in electrochemical reactions is heavily limited due to the non-conductivity of the reduction/oxidation products. In this paper, the doping level of individual PANI nanotubes was substantially enhanced using nitrite as an electron acceptor in sulfuric acid aqueous solution as recorded by the nano-impact method. The charge transferred to one single tube during reduction process is close to the theoretical value of 170±112 pC per tube (assuming 2-electron reduction for the PANI tubes studied), while the charge during PANI oxidation is dramatically decreased. Reaction processes are proposed based on the oxidative properties of nitrite in acid solution. UV-visible spectroscopy analysis further confirms an oxidation-reduction reaction between PANI and nitrite. In contrast the electrochemical reaction of ensembles (21 μg cm^-1 ) of PANI tubes on glassy carbon electrodes simply show limited electrocatalytic activity.

Fabrication and characterisation of magnetic graphene oxide incorporated Fe3O4@polyaniline for the removal of bisphenol A, t-octyl-phenol, and α-naphthol from water

In this study, we fabricated a novel material composed of magnetic graphene oxide incorporated Fe₃O₄@polyaniline (Fe₃O₄@PANI-GO) using a modified Hummers' method, solvothermal, and two-step polymerisation method. The resulting products were characterised by transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The results indicated that magnetic Fe₃O₄@PANI particles were successfully loaded onto the surface of the graphene oxide. Further Fe₃O₄@PANI-GO was investigated to remove bisphenol A(BPA), α-naphthol, and t-octyl-phenol (t-OP) from water samples by magnetic solid phase extraction. Under the optimal conditions, the Fe₃O₄@PANI-GO composite exhibited good adsorption capacity for t-OP, BPA, and α-naphthol, and the adsorption of these followed a pseudo-second-order kinetic model. Adsorption isotherms fit the Langmuir model, and the adsorption was an endothermic and spontaneous process. This work indicated that Fe₃O₄@PANI-GO earned great application prospect for removing phenolic contaminants from polluted water.

Assessing the electrochemical properties of polypyridine and polythiophene for prospective applications in sustainable organic batteries

In this work, a theoretical protocol has been developed to calculate redox potentials in solution within the framework of the density functional theory and using continuous solvation model.

Ultra-sensitive polyaniline–iron oxide nanocomposite room temperature flexible ammonia sensor

We report for the first time a room temperature smart NH₃sensor based on PAni–Fe₂O₃nanocomposite loading on flexible PET substrate byin situchemical oxidative polymerization method.

Synthesis of polyaniline/TiO2 nanocomposites with metalloporphyrin and metallophthalocyanine catalysts

Inorganic nanoparticles combined with conducting polymers provide interesting physical properties. This research describes the aniline polymerization taking place on the nanoparticles surface by catalytic oxidative polymerization with metalloporphyrin and metallophthalocyanine. In this way, the core-shell structure of the polyaniline/ TiO2 nanocomposites was obtained. The comparison of results demonstrates that porphyrin is a better catalyst than phthalocyanine for synthesis of nanocomposite. The morphology and composition of the nanocomposites were characterized by techniques such as SEM and FT-IR spectroscopy. TGA analysis showed that the nanocomposites, synthesized with iron(III) tetrasulfonated tetraphenyl porphyrin and iron(II) tetrasulfonated phthalocyanines, contained 10% and 5% conducting polyaniline (by mass), respectively. Eventually, the voltammograms revealed that these nanocomposites were electroactive and there was a linear relationship between the anodic and cathodic peak current values and scan rates.

Influence of external voltage on the reprotonated polyaniline films by Fourier Transform Infrared spectroscopy

In this paper, we reported the electrical fourier transform infrared (FT-IR) spectra measurements on the reprotonated polyaniline (PANI) thin films. Application of external voltage reduced the intensity in FT-IR spectra and resulted in the shift of band situation. The FT-IR spectra as a function of temperature were also conducted in order to investigate the effect of Joule heating. We found that the influence of CC of phenyl units and the CC of quinoid were quite different as a function of external voltage and temperature. The current-voltage (I-V) curves of the PANI film measured in the range of 0-175 V showed that the resistance kept constant at 0-75 V while it increased from 75 to 175 V. The I-V curves confirmed the presence of Joule heating effect during 75-175 V. According to the experiment results, we concluded that external voltage could produce large average hopping energy, which allowed the charge transfer by hopping between the conducting domains during 0-75 V. The deprotonation of PANI was caused by Joule heating effect, resulting in the decreasing conductivity from 75 to 175 V.

Application of polyaniline for the reduction of toxic Cr(VI) in water

Various oxidation states of polyaniline, as film and powder, were used for reduction of highly toxic Cr(VI) to less toxic Cr(III) ion. The effects of various parameters such as synthesis method, physical and oxidation state of polyaniline, film thickness, solution pH and initial Cr(VI) concentration on the kinetics and efficiency of reduction process were investigated. Results showed that a very broad concentration range of Cr(VI) solutions (10-10(5)ppb by emeraldine base and 10-10(6.5)ppb by leucoemeraldine) can be efficiently (>98%) reduced by polyaniline as film or powder. Cr(VI) solutions with concentrations higher than these ranges were caused to the overoxidation and degradation of polymer. Decreasing of solution pH, increased the kinetics and performance of reduction process, but lowered the Cr(VI) concentration ranges caused the overoxidation and degradation of the polymer. Higher reduction efficiencies were obtained for thicker electrochemically synthesized polyaniline films and for thinner chemically prepared polyaniline free standing films. The ability or capacity of various forms of polyaniline in Cr(VI) reduction was evaluated as the milligrams of Cr(VI) reduced by one gram of various forms of polyaniline.

In vivo measurements of changes in pH triggered by oxalic acid in leaf tissue of transgenic oilseed rape

Oxalic acid (OA), a non-host-specific toxin secreted by Sclerotinia sclerotiorum during pathogenesis, has been demonstrated to be a major phytotoxic and pathogenic factor. Oxalate oxidase (OXO) is an enzyme associated with the detoxification of OA, and hence the introduction of an OXO gene into oilseed rape (Brassica napus L.) to break down OA may be an alternative way of increasing the resistance of the plant to Sclerotinia sclerotiorum. In order to investigate the activation of OXO in transgenic oilseed rape, a convenient and accessible method was used to monitor changes in pH in response to stress induced by OA. The pH sensor, a platinum microcylinder electrode modified using polyaniline film, exhibited a linear response within the pH range from 3 to 7, with a Nernst response slope of 70 mV/pH at room temperature. The linear correlation coefficient was 0.9979. Changes induced by OA in the pH values of leaf tissue of different oilseed rape species from Brassica napus L. were monitored in real time in vivo using this electrode. The results clearly showed that the transgenic oilseed rape was more resistant to OA than non-transgenic oilseed rape.

Covalent immobilization of cholesterol esterase and cholesterol oxidase on polyaniline films for application to cholesterol biosensor

Cholesterol esterase (ChEt) and cholesterol oxidase (ChOx) have been covalently immobilized on electrochemically prepared polyaniline (PANI) films. These PANI/ChEt/ChOx enzyme films have been characterized using UV-visible, Fourier transform infrared (FTIR) spectroscopy and scanning electron microscopy (SEM). Electrochemical behavior of these films has been studied using cyclic voltammetry (CV) and amperometric techniques, respectively. The PANI/ChEt/ChOx enzyme films show broad oxidation peak from 0.2 to 0.5 V. These PANI/ChEt/ChOx biosensing electrodes have a response time of about 40s, linearity from 50 to 500 mg/dl of cholesterol oleate concentration. These PANI/ChEt/ChOx films are thermally stable up to 46 degrees C. This polyaniline based cholesterol biosensor has optimum pH in the range of 6.5-7.5, sensitivity as 7.5x10(-4) nA/mg dl and a lifetime of about 6 weeks.

Electroactive Polymer-Based Devices for e-Textiles in Biomedicine

This paper describes the early conception and latest developments of electroactive polymer (EAP)-based sensors, actuators, electronic components, and power sources, implemented as wearable devices for smart electronic textiles (e-textiles). Such textiles, functioning as multifunctional wearable human interfaces, are today considered relevant promoters of progress and useful tools in several biomedical fields, such as biomonitoring, rehabilitation, and telemedicine. After a brief outline on ongoing research and the first products on e-textiles under commercial development, this paper presents the most highly performing EAP-based devices developed by our lab and other research groups for sensing, actuation, electronics, and energy generation/storage, with reference to their already demonstrated or potential applicability to electronic textiles.