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In this study, the conversion of TiO2 nanotubes (NTs) into barium titanate (BaTiO3) exploiting a two-step low-temperature synthesis method is reported. Vertically oriented TiO2 NT arrays were grown by ultra-fast anodic oxidation of titanium foils in ammonium fluoride-based electrolytic solution and then converted into BaTiO3 exploiting a shape-preserving hydrothermal treatment. A parametric study was carried out taking into account the effect of alkalinity, temperature and reaction time on the converted materials. The crystalline phase and morphology of the nanostructured material were investigated by means of X-ray diffraction, scanning and transmission electron microscopy, evidencing the formation of ordered polycrystalline BaTiO3 arrays. The tetragonal phase of the obtained material was revealed by Raman spectroscopy and its ferroelectric behavior was confirmed by domain switching observation during electrical characterization. The tube-like nanostructured arrays of BaTiO3 could open the way for new applications of energy harvesting materials where easy and low temperature processing, controlled morphology and functional properties are required. [ABSTRACT FROM AUTHOR]

Highlights: [•] TiO2 nanotube (NT) arrays were grown by potentiostatic anodization of Ti foil. [•] Photoanodes were prepared by mixing NT powder into nanoparticle (NP) dispersion. [•] DSCs were assembled with different NT content. [•] The composite photoanodes show higher efficiency and electron lifetime than NP ones. [Copyright &y& Elsevier]

Highlights: [•] Fabrication and characterization of TiO2 nanotube (NT) arrays by anodic oxidation. [•] Nts detachment and integration in front-side illuminated Dye-sensitized Solar Cells. [•] Nanoparticle (NP) film implemented as adhesion layer. [•] Only one thermal step required for NT crystallization and NP/NT interface formation. [•] TiO2 NTs-based DSC shows a huge increase in electrons transport properties. [Copyright &y& Elsevier]

Highlights: [•] TiO2 nanotubes (NTs) are grown onto a Ti foil by ultra-fast anodic oxidation. [•] NTs exhibit noticeable stability and capacity retention after prolonged cycling. [•] NTs show improved durability (>1100 cycles) at a very high C-rate. [•] Short diffusion path and fast kinetics are responsible for superior performance. [•] TiO2 NTs are interesting candidate for next generation micro Li-based cells. [Copyright &y& Elsevier]

The spread of wearable and flexible electronics devices has been accelerating in recent years for a wide range of applications. Development of an appropriate flexible power source to operate these flexible devices is a key challenge. Supercapacitors are attractive for powering portable lightweight consumer devices due to their long cycle stability, fast charge-discharge cycle, outstanding power density, wide operating temperatures and safety. Much effort has been devoted to ensure high mechanical and electrochemical stability upon bending, folding or stretching and to develop flexible electrodes, substrates and overall geometrically-flexible structures. Supercapacitors have attracted considerable attention and shown many applications on various scales. In this review, we focus on flexible structural design under six categories: paper-like, textile-like, wire-like, origami, biomimetics based design and micro-supercapacitors. Finally, we present our perspective of flexible supercapacitors and emphasize current technical difficulties to stimulate further research. [ABSTRACT FROM AUTHOR]

In this manuscript a near-room temperature crystallization process of anodic nanotubes from amorphous TiO2 to anatase phase with a fast 30 minutes treatment is reported for the first time. This method involves the exposure of as-grown TiO2 nanotubes to water vapor flow in ambient atmosphere. The water vapor-crystallized samples are deeply investigated in order to gain a whole understanding of their structural, physical and chemical properties. The photocatalytic activity of the converted material is tested by dye degradation experiment and the obtained performance confirms the highly promising properties of this low-temperature processed material. [ABSTRACT FROM AUTHOR]

Porous organic polymers are versatile platforms, easily adaptable to a wide range of applications, from air filtering to energy devices. Their fabrication via vat photopolymerization enables them to control the geometry on a multiscale level, obtaining hierarchical porosity with enhanced surface-to-volume ratio. In this work, a photocurable ink based on 1,6 Hexanediol diacrylate and containing a high internal phase emulsion (HIPE) is presented, employing PLURONIC F-127 as a surfactant to generate stable micelles. Different parameters were studied to assess the effects on the morphology of the pores, the printability and the mechanical properties. The tests performed demonstrates that only water-in-oil emulsions were suitable for 3D printing. Afterwards, 3D complex porous objects were printed with a Digital Light Processing (DLP) system. Structures with large, interconnected, homogeneous porosity were fabricated with high printing precision (300 µm) and shape fidelity, due to the addition of a Radical Scavenger and a UV Absorber that improved the 3D printing process. The formulations were then used to build scaffolds with complex architecture to test its application as a filter for CO2 absorption and trapping from environmental air. This was obtained by surface decoration with NaOH nanoparticles. Depending on the surface coverage, tested specimens demonstrated long-lasting absorption efficiency. [ABSTRACT FROM AUTHOR]

The ever‐increasing amount of batteries used in today's society has led to an increase in the demand of lithium in the last few decades. While mining resources of this element have been steadily exploited and are rapidly depleting, water resources constitute an interesting reservoir just out of reach of current technologies. Several techniques are being explored and novel materials engineered. While evaporation is very time‐consuming and has large footprints, ion sieves and supramolecular systems can be suitably tailored and even integrated into membrane and electrochemical techniques. This review gives a comprehensive overview of the available solutions to recover lithium from water resources both by passive and electrically enhanced techniques. Accordingly, this work aims to provide in a single document a rational comparison of outstanding strategies to remove lithium from aqueous sources. To this end, practical figures of merit of both main groups of techniques are provided. An absence of a common experimental protocol and the resulting variability of data and experimental methods are identified. The need for a shared methodology and a common agreement to report performance metrics are underlined. [ABSTRACT FROM AUTHOR]

In this study, a novel functionalized graphene oxide (fGO) is proposed for application in water desalination. The fGO is obtained with a simple and scalable method. Pristine GO is functionalized with (2‐(acryloyloxy)ethyl)trimethylammonium through a two‐step functionalization. Then, it is mixed with activated carbon and coated onto a metallic current collector. Material characterization techniques such as electron microscopy, thermal analyses, and infrared spectroscopy are employed to study the physical and chemical structures of the proposed materials. This process provides a porous electrode useful for capacitive deionization (CDI). The desalination performance is compared to the performance of bare activated carbons, showing a remarkable improvement. The final device reaches a value of around 17 mg g‐1 of salt removal, with a charge efficiency of 98%. The findings from this study lay the groundwork for future research, contributing in increasing the existing knowledge on materials for CDI. [ABSTRACT FROM AUTHOR]

The study of the degradation process occurring in Dye-sensitized Solar Cells (DSCs) is still a hot topic, in view of the final industrialization and application of this class of devices. Currently the long-term analysis of DSCs is carried out on the entire devices, while the monitoring of cell components cannot be performed in situ directly on the materials, but only through indirect methods. In this paper we report on the analysis of two different kinds of Pt counter electrodes through direct measurements performed under real operating conditions, thanks to the use of a home-made microfluidic housing system, which allows the opening and the investigation of the cell components. The counter electrode samples were studied through X-Ray Photoelectron Spectroscopy, Field Emission Scanning Electron Microscopy, Energy Dispersive X-ray Spectroscopy, UV–visible Spectroscopy and Electrochemical Impedance Spectroscopy for a period longer than 1 year. The results showed that the performances of both classes of Pt counter electrodes remained stable for all the investigation period, despite some slight variation of the morphology. DSCs fabricated employing aged counter electrodes exhibited the same photovoltaic performance behavior of reference cells using fresh-produced counter electrodes, thus demonstrating that both class of materials do not undergo degradation during normal operating conditions. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we present the fabrication and characterization of Dye-Sensitized Solar Cells exploiting graphene/TiO2 nanocomposite photoanodes produced by in-situ catalytic reduction of graphene oxide. The graphene oxide reduction to graphene was obtained in a solution-based process during the thermal treatment of the composite, catalyzed by the presence of TiO2 nanoparticles, as confirmed by X-ray photoelectron spectroscopy. The carbon nanostructures act as 2D conductive support path for the photogenerated electrons inside the nanostructured semiconductor electrode, as evidenced by the charge transport properties and recombination kinetics estimated by electrochemical impedance spectroscopy. The presence of graphene sheets led to an increase of the electron lifetime, due to reduction of recombination of charge carriers; moreover, the devices assembled with nanocomposite photoanodes showed an increase of the generated photocurrent, due to the improvement of the transport properties. The optimal value of graphene oxide in TiO2 was found at a concentration of 0.25wt%, which corresponds to double photoconversion efficiency with respect to the bare TiO2-based cells. [Copyright &y& Elsevier]

• rGO_Cu 2 O imperfect micro-cube nanocomposite synthesis for charge storage. • Conversion of CuO phase to Cu 2 O by Ascorbic acid. • Proving the diffusion of Na+ ions into the nanocomposite by XPS study. • Supercapattery behavior of hybrid binder-free nanocomposite. • Keeping 87.7% of initial stored charge after 10,000 cycles. This paper reports the exploitation of Cu 2 O nanoparticles and reduced graphene oxide (rGO) in a sonication treatment for the production of rGO- Cu 2 O imperfect micro-cubes nanocomposite. This strategy was implemented in order to fabricate a hybrid binder-free electrode for electrochemical energy storage into supercapacitors. Instead of hazardous chemical compounds, Ascorbic acid was simultaneously used as reducing agent and morphology controller of the nanocomposite as well. The structural properties of rGO-Cu 2 O imperfect micro-cubes nanocomposite were studied by X-Ray diffraction (XRD) analyses, field emission scanning electron and transmission electron microscopy (FE-SEM and TEM) imaging, energy dispersive X-ray (EDX) elemental mapping, X-ray photoelectron spectroscopy (XPS) and surface area analyses. Based on structural investigation, the rGO-Cu 2 O nanocomposite with the morphology of attached Cu 2 O imperfect micro-cubes to rGO nanosheets possessing a high surface area containing pores and channels in different sizes was used as electrode materials for the charge storage. Electrochemical measurements including cyclic voltammetry (CV), galvanostatic charge-discharge (GCD), electrochemical impedance spectroscopy (EIS) and XPS analysis revealed that rGO-Cu 2 O imperfect micro-cubes nanocomposite modified electrode without binder has used three distinct processes of forming electrochemical double layer, redox reactions and ion diffusion for charge storage somehow it is introduced as a hybrid binder-free electrode. According to the GCD analysis, the stored charge value was calculated 960 C.g−1 at current density of 1 A.g−1, the cycling stability was examined in that the 87% of initial stored charge value was remained after 10,000 cycles. [ABSTRACT FROM AUTHOR]

[Display omitted] • Bifacial and tandem configurations were combined for the first time in DSSC. • Top efficiency of 14,96% was obtained for a DSSC using iodine-based redox couple and ruthenium-based dye. • A bifaciality factor of 0.97 was obtained with an innovative yet simple fabrication strategy. Over the last three decades, dye-sensitized solar cells (DSSCs) have received a lot of attention, reaching record efficiencies under AM 1.5G illumination slightly over 10%. However, these values are lower than other competing photovoltaic systems. The performance of DSSCs has to be further enhanced in order to have a substantial influence and application potential in the field of photovoltaics. Herein we propose a new intriguing strategy to take advantage of two concepts well known in the field of photovoltaics, such as the tandem configuration and the bifaciality, never applied at the same time to DSSCs. Thanks to the combination of these strategies, we are noteworthy able to overcome the maximum efficiency ever obtained for a traditional DSSC based on iodide/triiodide redox couple and Ru-based dye, as high as 14.96%. Our findings open the way to further enhancement with optimized DSSCs configuration. [ABSTRACT FROM AUTHOR]

During the last years, Internet of Things has become a prominent topic of technical, social, and economic importance. One of the main consequences is the high demand for energy and power density from small energy storage devices. In this field the laser induced graphene (LIG) has become a promising material to produce flexible micro-supercapacitors. The issue with this material is that the performances are strongly restrained by its limited surface area and the relatively low conductivity. In this work we improve the performance of a LIG supercapacitor by decorating its surface through electrophoresis: one electrode will be decorated with metal nitrides and metal carbides (MXenes), the other with manganese oxide. These two materials have appreciable conductivity and pseudocapacitance. Electrochemical measurements have been carried out on the two electrodes separately. After a charge balancing, the device has been sealed in pouch and tested. [ABSTRACT FROM AUTHOR]

• Newly proposed coating procedure to obtain thin membrane over carbon based materials. • Substitution of standard binder and improvement of the adhesion performances for supercapacitor electrode application. • Use of cation exchange membrane in thin film over a carbon based electrode resulting in an enlargement in operating voltage window, increase in coulombic efficiency and reduction of ESR. In this work we report a green procedure for the infiltration of a SPEEK solution into a porous carbon electrode resulting in a thin-film cation exchange membrane. The electrodes have been investigated by a morphological point of view, showing the formation of a thin coating infiltrated into the porous carbonaceous matrix, while mechanical peeling of a tape demonstrated the adhesion of the proposed layer. The fabricated electrodes have been analyzed by electrochemical measurement. The 3-electrode cyclic voltammetry measurements allowed to verify the voltage window resulting in an improved negative potential, while the electrochemical impedance spectroscopy showed a reduction of the electrical resistance. The SPEEK electrode was used in a supercapacitor and deeply characterized by electrochemical analysis. The reported findings demonstrate for the first time the possibility to exploit a cation exchange material in thin film configuration for supercapacitor application with improved performance of the device and exclusively involving the use of nontoxic reagents. [ABSTRACT FROM AUTHOR]

The scientific interest in integrated energy harvesting and storage (HS) devices has increased exponentially in the last decade since they represent an optimal solution to power portable electronic devices and low consuming Internet of Thing (IoT) sensor nodes. The integration of energy storage devices with photovoltaics can allow to avoid problems such as continuous battery replacement and periodic maintenance, reducing overall costs. In this context, dye sensitized solar cells (DSSCs) integrated with a supercapacitor represent the best choice in terms of lifetime, charge-discharge efficiency, and simplicity of connection avoiding electrical signal conditioning between the two devices. DSSCs have many similarities with supercapacitors, with the only aspect that remains uncovered being the sealing of the device. Herein we propose a common vacuum sealing technology for the integration of a supercapacitor and a DSSC made with shared current collectors, to maximize the integration between the two technologies. The HS device showed a maximum overall photon to electrical conversion and storage efficiency (OPECSE) of 6.10% under only 0.1 SUN illumination, thanks to the high photoconversion efficiency showed by the pouch sealed DSSC, equal to 6.62%. The HS device showed a high stability under bending condition and repeated photo-charge/discharge cycling. [Display omitted] • Vacuum sealing was used for the first time to encapsulate dye-sensitized solar cells. • Pouch-sealing enabled a flexible integrated energy harvesting and storage system. • A DSSC and a EDLC were integrated with a simple and scalable encapsulation technique. [ABSTRACT FROM AUTHOR]

Abstract The growing interest in developing wearable energy storage devices requires the identification of suitable materials for the fabrication of their components. In this paper we report a new asymmetric fiber-shaped supercapacitor exploiting a composite of hematite and reduced graphene oxide aerogel obtained by a hydrothermal synthesis in presence of green extract as anode material and electrodeposited nanostructured MnO x as cathode. The three dimensional arrangement of the graphene flakes during the hydrothermal self-assembly process provides a highly conductive porous matrix with high surface area and, most importantly, a pores structure able to guarantee the rapid diffusion of the electrolyte ions and a fast electron transport. By simply modifying the hydrothermal recipe adding a dispersion of hematite nanoparticles, obtained using olive leaves extract as green surfactant, it is possible to obtain the decoration of the graphene network with the pseudocapacitive material. The resulting nanocomposite rGO/Fe 2 O 3 aerogel exhibits excellent pseudocapacitive behaviour and it is used, in combination with MnO x nanostructured electrode, to fabricate a flexible fiber-shaped device exhibiting superior rate capability and bending stability. The use of a green surfactant during the synthesis opens up new avenues for the fabrication of environmentally friendly electrodes for wearable energy storage applications. Graphical abstract Image 1 [ABSTRACT FROM AUTHOR]

Energy storage devices integrated into textiles have emerged as a significant strategy for electronic applications. In this context, in the present paper novel flexible devices were developed, in which the control of both the electrode characteristics and the solid-electrolyte properties allows to build all-solid-state wire-shaped supercapacitors that can be integrated and waved. The proposed device was assembled using modified CNT yarns as electrodes and a blend of ionic liquid, Li salt and poly(ethylene glycol) acrylate to fabricate the solid-polymeric electrolyte. Excellent performance in terms of both electrochemical parameters and stability were obtained. These achievements are possible thanks to the coupling of asymmetric CNT yarns, following an optimization of the activation procedure together with the improvement of the polymeric electrolyte. The results show a capacitance as high as 1.8 mF/cm, energy density of 1.3 μWh/cm and a capacitance retention higher than 100% over 1200 cycles. [Display omitted] • True full solid state high-power device in the shape of a flexible wire storage element. • The approach is extended as a proof-of-concept to energy device applications in which a high-aspect ratio of the materials is required with no leakage of a high conductive electrolyte. • The preparation method of the electrolytes points out the possibility to modulate their composition (solid salts, ionic liquid, proportion among polymeric precursors) for a specific purpose. • Devices made either by using modified and unmodified CNT yarns and a blend of ionic liquid, Li salt and poly(ethylene glycol) acrylates. • Extreme flexibility even under high temperatures (125 °C) [ABSTRACT FROM AUTHOR]

• LIG was demonstrated as a counter electrode for DSSC with Cu-based electrolyte. • LIG-based DSSC and LIG-based EDLC were integrated in a self-powered storage system. • LIG outperformed PEDOT as flexible counter electrode in DSSC with Cu-based electrolyte. Dye-sensitized solar cells (DSSCs) are gaining a newfound interest thanks to their superior ability to harvest indoor light with efficiency higher than other photovoltaic technologies. This study reports, for the first time, the possibility of using laser-induced graphene (LIG) as a flexible counter electrode material for DSSCs. A flexible LIG (F-LIG) electrode was fabricated by direct laser writing of a polyimide film, without the need of a starting conductive substrate. The prepared electrodes showed a higher catalytic activity towards the reduction of I 3 −/I−with respect to a more expensive Pt-based counter electrode. Moreover, the F-LIG electrodes outperformed electrodeposited PEDOT as a catalytic material for reduction of a copper bipyridyl complex (Cu(II/I)(tmby) 2 TFSI 2/1) electrolyte. The F-LIG based DSSCs showed an open circuit voltage as high as 0.94 V and an increase in photoconversion efficiency higher than 60% with respect to the PEDOT-based counterpart, stepping from 3.08% to 4.96%. Thanks to the easy one-step laser-based fabrication process, the LIG-based DSSC was integrated with a LIG-based supercapacitor (SC), obtaining a flexible energy harvesting and storage system that was able to self-charge both under simulated solar illumination and under indoor artificial illumination, appearing to be a promising energy source for the next generation of self-powered connected Internet of Things devices. [Display omitted] [ABSTRACT FROM AUTHOR]

In recent years scaling-down approaches on supercapacitors has led to the definition of Micro-Supercapacitors (μSC). The demand for these devices is increasing for many applications in microelectronics, such as wearable energy storage and self-powered sensors. Recently, many efforts have been made to achieve good results in terms of power and energy densities. However, the current research challenge is to develop a sustainable chain production, involving eco-friendly materials, such as water-based electrolytes, organic binders and low-impact active material. This work presents a hybrid μSC using low impact materials and a fully water-based solution. Different approaches were adopted for patterning the current collectors and for the deposition of the active materials. The material chosen as anode was MnO 2 deposited by electroplating, which presents pseudocapacitive behavior. The active material used for the cathode was Activated Carbon (AC), deposited by drop-casting, which works through the electric double layer (EDL) capacitance effect. The electrolyte was 1 M Na 2 SO 4 in water. We investigated the addition of an interlayer micro-structure made of Dendritic-Gold (D-Gold). The results show that such a layer seems to have positive effects in terms of wettability and mechanical stability, enhancing the adhesion of the active material. Electron microscopy measurement shows the characteristic tree-like shape of the layer. The device reports a capacitance of about 14 to 23 mF cm-2 and a large voltage window equal to 1.6 V. The present research explores, for the first time, the effects of dendritic gold in planar electrochemical capacitors. The findings should give an important contribution for boost energy storage densities in the field of 2D micro-supercapacitors. [Display omitted] [ABSTRACT FROM AUTHOR]

The study of energy storage devices able to work in harsh environments is becoming of paramount importance. Numerous applications require devices able to sustain extreme temperatures but often the pressure is discarded. Herein we present the evaluation of the energy storage performance of a prototype electrochemical supercapacitor from room temperature and ambient pressure up to 170 °C and 640 bar. The supercapacitor is fabricated by exploiting activated carbon-based electrodes and an ionic liquid as electrolyte. [PYR14][TFSI] has been selected for this scope since it possesses suitable features for the investigated case of study. The whole device was sealed in a vacuum pouch and tested into a customized high-temperature high-pressure (HTHP) test bench. The device shows typical EDLC behavior in the whole HTHP region with capacitive response ranging from the low value of 46.4 mF cm−2 at {RT, 600 bar} up to 84.6 mF cm−2 at {175 °C, 640 bar}, with a reference value of 58.8 mF cm−2. At these points, the rated energy values are 92.8 mWh cm−2 and 169.1 mWh cm−2. We observed that pressure mainly acts on dissipative parasite components of the device while temperature strongly impinges transport properties and capacitance as expected from literature results. [ABSTRACT FROM AUTHOR]

Abstract: In the present paper we demonstrate the efficient use of shape controlled flower-like ZnO (Zinc oxide) nanostructured particles as multifunctional electrode for both energy conversion and storage applications, i.e. Dye-sensitized Solar Cells (DSCs) and lithium-ion batteries. As regards DSC (Dye-sensitized Solar Cell) device, ZnO flower-like particles, prepared by a simple, low-cost and reliable hydrothermal method under mild reaction temperature, are efficiently used as photoanode in a microfluidic architectured cell in combination with NMBI (N-methylbenzimidazole), employed as additive of the electrolytic solution for the first time in a ZnO-based DSC. We obtain a remarkable sunlight conversion efficiency of 3.6%. As regards storage applications, a stable long-term ambient temperature cycling behavior in lithium cell is demonstrated, even at increasingly higher currents. Remarkable charge-discharge efficiency and specific capacity are obtained up to 200 cycles, which is the highest number of cycles reported so far for similar systems. Noteworthy, such results are achieved without the addition of foreign additives, nor during the synthesis process neither during the electrode preparation, and also no carbon coating on ZnO surface is used. The originality of the present paper consists not only in showing for the first time the efficient operation of such ZnO particles as anode in Li-ion batteries for prolonged cycling, but also in demonstrating the versatile and multifunctional use of the same material for two different energy related applications. The reported results enlighten indeed the promising prospects of the flower-like ZnO nanostructured material for the successful implementation as stable and long-term performing anodic material in the next generation of both energy conversion and storage devices. [Copyright &y& Elsevier]

Abstract: Spongelike nanostructured zinc films were grown by room temperature sputtering processes and pure wurzitic zinc oxide nanostructured films were obtained by a subsequent thermal annealing process. This method allowed growing films with a thickness of a few micrometers with a relatively short deposition time. A study on the influence of the process parameters on the morphology of the films was carried out. The radio frequency power applied to the cathode appeared to be the main factor in order to achieve nanostructures with different morphological features. The physical and chemical characteristics of the nanostructured ZnO obtained with the method herein described make it suitable to be used as photoanode in Dye-sensitized Solar Cells. [Copyright &y& Elsevier]

The aim of this paper is to shed light on the application of graphene oxide (GO) membranes for the selective removal of benzene, toluene, and xylene (BTX) from wastewater. These molecules are present in traces in the water produced from oil and gas plants and are treated now with complex filtration systems. GO membranes are obtained by a simple, fast, and scalable method. The focus of this work is to prove the possibility of employing GO membranes for the filtration of organic contaminants present in traces in oil and gas wastewater, which has never been reported. The stability of GO membranes is analyzed in water solutions with different pH and salinity. Details of the membrane preparation are provided, resulting in a crucial step to achieve a good filtration performance. Material characterization techniques such as electron microscopy, x-ray diffraction, and infrared spectroscopy are employed to study the physical and chemical structure of GO membranes, while gas chromatography, UV-visible spectroscopy, and gravimetric techniques allow the quantification of their filtration performance. An impressive rejection of about 90% was achieved for 1 ppm of toluene and other pollutants in water, demonstrating the excellent performance of GO membranes in the oil and gas field. [ABSTRACT FROM AUTHOR]

• The combination of LIG and ionic liquid is proposed to fabricate flexible and high temperature micro-supercapacitor. • This flexible device demonstrates excellent stability even at high bending condition and at 100 °C. • The proposed de-rated voltage analysis define a safe procedure to characterize supercapacitor at high temperature. • This approach will allow to avoid the deterioration of the system performance. Herein we report the fabrication and electrochemical characterization of a novel type of supercapacitor composed of laser-induced graphene (LIG) electrodes, achieved by the laser-writing of polyimide foils, and 1-Butyl-1-methylpyrrolidinium bis(trifluoromethanesulfonyl)imide ionic liquid as electrolyte. This combination allows the development of a flexible microsupercapacitor suitable for harsh environment application. The influence of several parameters is evaluated with the aim of maximizing the performance of the flexible pouch-bag devices, such as the laser-writing conditions, type of electrode layout and amount of nitrogen-doping. Among them, the laser writing conditions are found to strongly influence the areal capacitance allowing to achieve about 4 mF cm−2, as measured from the galvanostatic charge-discharge measurement at 10 µA cm−2, with a maximum operating potential range of 3 V at 25 °C. In order to probe the potential application of such device, i) flexible pouch architecture and ii) high temperature measurements (considering harsh environment field) are investigated. This type of flexible device exhibits energy and power density as high as 4.5 µWh cm−2 and 90.5 µW cm−2, respectively, high cycling stability as well as acceptable coulombic efficiency above 97% demonstrating good stability even at high bending condition (1.25 cm of bending radius). The electrochemical measurements increasing temperature up to 100 °C reveal a 300% of rise in capacitance and 43% of increment in energy density at de-rated voltage. The obtained energy storage performance are comparable to the best data ever reported for a microsupercapacitor for high temperature application. Moreover, a de-rated voltage analysis (DVA) is proposed as a safe procedure to characterize an energy storage device in an extended temperature range without compromising the system performances. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Emerging technologies, such as portable electronics, have had a huge impact on societal norms, such as access to real time information. To perform these tasks, portable electronic devices need more and more accessories for the processing and dispensation of the data, resulting in higher demand for energy and power. To overcome this problem, a low cost high-performing flexible fiber shaped asymmetric supercapacitor was fabricated, exploiting 3D-spinel manganese oxide Mn3O4 as cathode and 2D molybdenum disulfide MoS2 as anode. These asymmetric supercapacitors with stretched operating voltage window of 1.8 V exhibit high specific capacitance and energy density, good rate capability and cyclic stability after 3000 cycles, with a capacitance retention of more than 80%. This device has also shown an excellent bending stability at different bending conditions. [ABSTRACT FROM AUTHOR]

Considering the worldwide market of batteries and supercapacitors, the (partial or total) replacement of conventional fossil-derived carbonates with bio-based ones in electrolyte formulations would allow the production of safer and more sustainable devices. In this work, embracing the 7th principle of green chemistry, glycerol derivatives (namely glycerol carbonate and solketal carbonate) are tested as solvents and additives for electrolyte formulations. Glycerol carbonate is innovatively employed as promising electrolyte solvent for electric double-layer capacitors with excellent performances. On the other hand, a solketal carbonate-laden liquid electrolyte is investigated for potassium-based batteries, showing a rather stable electrochemical behaviour and performance close to those of commercial oil-derived alternatives., (© 2024 Wiley‐VCH GmbH.)

Copper oxide nanowires (NWs) are promising elements for the realization of a wide range of devices for low-power electronics, gas sensors, and energy storage applications, due to their high aspect ratio, low environmental impact, and cost-effective manufacturing. Here, we report on the electrical and thermal properties of copper oxide NWs synthetized through thermal growth directly on copper foil. Structural characterization revealed that the growth process resulted in the formation of vertically aligned NWs on the Cu growth substrate, while the investigation of chemical composition revealed that the NWs were composed of CuO rather than Cu 2 O. The electrical characterization of single-NW-based devices, in which single NWs were contacted by Cu electrodes, revealed that the NWs were characterized by a conductivity of 7.6 × 10 -2 S∙cm -1 . The effect of the metal-insulator interface at the NW-electrode contact was analyzed by comparing characterizations in two-terminal and four-terminal configurations. The effective thermal conductivity of single CuO NWs placed on a substrate was measured using Scanning Thermal Microscopy (SThM), providing a value of 2.6 W∙m -1 ∙K -1 , and using a simple Finite Difference model, an estimate for the thermal conductivity of the nanowire itself was obtained as 3.1 W∙m -1 ∙K -1 . By shedding new light on the electrical and thermal properties of single CuO NWs, these results can be exploited for the rational design of a wide range of optoelectronic devices based on NWs.

Methanogenic archaea stand out as multipurpose biocatalysts for different applications in wide-ranging industrial sectors due to their crucial role in the methane (CH 4 ) cycle and ubiquity in natural environments. The increasing demand for raw materials required by the manufacturing sector (i.e., metals-, concrete-, chemicals-, plastic- and lubricants-based industries) represents a milestone for the global economy and one of the main sources of CO 2 emissions. Recovery of critical raw materials (CRMs) from byproducts generated along their supply chain, rather than massive mining operations for mineral extraction and metal smelting, represents a sustainable choice. Demand for lithium (Li), included among CRMs in 2023, grew by 17.1% in the last decades, mostly due to its application in rechargeable lithium-ion batteries. In addition to mineral deposits, the natural resources of Li comprise water, ranging from low Li concentrations (seawater and freshwater) to higher ones (salt lakes and artificial brines). Brines from water desalination can be high in Li content which can be recovered. However, biological brine treatment is not a popular methodology. The methanogenic community has already demonstrated its ability to recover several CRMs which are not essential to their metabolism. Here, we attempt to interconnect the well-established biomethanation process with Li recovery from brines, by analyzing the methanogenic species which may be suitable to grow in brine-like environments and the corresponding mechanism of recovery. Moreover, key factors which should be considered to establish the techno-economic feasibility of this process are here discussed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher., (Copyright © 2023 Abdel Azim, Vizzarro, Bellini, Bassani, Baudino, Pirri, Verga, Lamberti and Menin.)

Permselectivity of a membrane is central for the development of electrochemical energy storage devices with two redox couples, such as redox flow batteries (RFBs). In RFBs, Br 3 - /Br - couple is often used as a catholyte which can cross over to the anolyte, limiting the battery's lifetime. Naturally, the development of permselective membranes is essential to the success of RFBs since state-of-the-art perfluorosulfonic acid (PFSA) is too costly. This study investigates membranes of graphene oxide (GO), polyvinylpyrrolidone (PVP), and imidazole (Im) as binder and linker, respectively. The GO membranes are compared to a standard PFSA membrane in terms of ionic conductivity (Na + ) and permselectivity (exclusion of Br - ). The ionic conduction is evaluated from electrochemical impedance spectroscopy and the permselectivity from two-compartment diffusion cells in a four-electrode system. Our findings suggest that the GO membranes reach conductivity and permselectivity comparable with standard PFSA membranes.

Renewable energy-based technologies and increasing IoT (Internet of Things) objects population necessarily require proper energy storage devices to exist. In the view of customized and portable devices, Additive Manufacturing (AM) techniques offer the possibility to fabricate 2D to 3D features for functional applications. Among the different AM techniques extensively explored to produce energy storage devices, direct ink writing is one of the most investigated, despite the poor achievable resolution. Herein, we present the development and characterization of an innovative resin which can be employed in a micrometric precision stereolithography (SL) 3D printing process for the fabrication of a supercapacitor (SC). Poly(3,4-ethylenedioxythiophene) (PEDOT), a conductive polymer, was mixed with poly(ethylene glycol) diacrylate (PEGDA), to get a printable and UV curable conductive composite material. The 3D printed electrodes were electrically and electrochemically investigated in an interdigitated device architecture. The electrical conductivity of the resin falls within the range of conductive polymers with 200 mS/cm and the 0.68 µWh/cm 2 printed device energy density falls within the literature range.

Graphene oxide (GO) has shown great potential as a membrane material due to its unique properties, including high mechanical strength, excellent thermal stability, versatility, tunability, and outperforming molecular sieving capabilities. GO membranes can be used in a wide range of applications, such as water treatment, gas separation, and biological applications. However, the large-scale production of GO membranes currently relies on energy-intensive chemical methods that use hazardous chemicals, leading to safety and environmental concerns. Therefore, more sustainable and greener approaches to GO membrane production are needed. In this review, several strategies proposed so far are analyzed, including a discussion on the use of eco-friendly solvents, green reducing agents, and alternative fabrication techniques, both for the preparation of the GO powders and their assembly in membrane form. The characteristics of these approaches aiming to reduce the environmental impact of GO membrane production while maintaining the performance, functionality, and scalability of the membrane are evaluated. In this context, the purpose of this work is to shed light on green and sustainable routes for GO membranes' production. Indeed, the development of green approaches for GO membrane production is crucial to ensure its sustainability and promote its widespread use in various industrial application fields.

Enabling green fabrication processes for energy storage devices is becoming a key aspect in order to achieve a sustainable fabrication cycle. Here, the focus was on the exploitation of the tragacanth gum, an exudated gum like arabic and karaya gums, as green binder for the preparation of carbon-based materials for electrochemical capacitors. The electrochemical performance of tragacanth (TRGC)-based electrodes was thoroughly investigated and compared with another water-soluble binder largely used in this field, sodium-carboxymethyl cellulose (CMC). Apart from the higher sustainability both in production and processing, TRGC exhibited a lower impact on the obstruction of pores in the final active material film with respect to CMC, allowing for more available surface area. This directly impacted the electrochemical performance, resulting in a higher specific capacitance and better rate capability. Moreover, the TRGC-based supercapacitor showed a superior thermal stability compared with CMC, with a capacity retention of about 80 % after 10000 cycles at 70 °C., (© 2020 The Authors. ChemSusChem published by Wiley-VCH GmbH.)

Background: Papillary urothelial neoplasm of low malignant potential (PUN-LMP) was introduced as a noninvasive, noncancerous lesion and a separate grade category in 1998. Subsequently, PUN-LMP was reconfirmed by World Health Organization (WHO) 2004 and WHO 2016 classifications for urothelial bladder tumors., Objectives: To analyze the proportion of PUN-LMP diagnosis over time and to determine its prognostic value compared to Ta-LG (low-grade) and Ta-HG (high-grade) carcinomas. To assess the intraobserver variability of an experienced uropathologist assigning (WHO) 2004/2016 grades at 2 time points., Materials and Methods: Individual patient data of 3,311 primary Ta bladder tumors from 17 hospitals in Europe and Canada were available. Transurethral resection of the tumor was performed between 1990 and 2018. Time to recurrence and progression were analyzed with cumulative incidence functions, log-rank tests and multivariable Cox-regression stratified by institution. Intraobserver variability was assessed by examining the same 314 transurethral resection of the tumorslides twice, in 2004 and again in 2018., Results: PUN-LMP represented 3.8% (127/3,311) of Ta tumors. The same pathologist found 71/314 (22.6%) PUN-LMPs in 2004 and only 20/314 (6.4%) in 2018. Overall, the proportion of PUN-LMP diagnosis substantially decreased over time from 31.3% (1990-2000) to 3.2% (2000-2010) and to 1.1% (2010-2018). We found no difference in time to recurrence between the three WHO 2004/2016 Ta-grade categories (log-rank, P = 0.381), nor for LG vs. PUN-LMP (log-rank, P = 0.238). Time to progression was different for all grade categories (log-rank, P < 0.001), but not between LG and PUN-LMP (log-rank, P = 0.096). Multivariable analyses on recurrence and progression showed similar results for all 3 grade categories and for LG vs. PUN-LMP., Conclusions: The proportion of PUN-LMP has decreased to very low levels in the last decade. Contrary to its reconfirmation in the WHO 2016 classification, our results do not support the continued use of PUN-LMP as a separate grade category in Ta tumors because of the similar prognosis for PUN-LMP and Ta-LG carcinomas., (Copyright © 2019 Elsevier Inc. All rights reserved.)

In the challenging scenario of anode materials for sodium-ion batteries, TiO 2 nanotubes could represent a winning choice in terms of cost, scalability of the preparation procedure, and long-term stability upon reversible operation in electrochemical cells. In this work, a detailed physicochemical, computational, and electrochemical characterization is carried out on TiO 2 nanotubes synthesized by varying growth time and heat treatment, viz. the two most significant experimental parameters during preparation. A chemometric approach is proposed to obtain a concrete and solid multivariate analysis of sodium battery electrode materials. Such a statistical approach, combined with prolonged galvanostatic cycling and density functional theory analysis, allows identifying anatase at high growth time as the TiO 2 polymorph of choice as an anode material, thus creating a benchmark for sodium-ion batteries, which currently took the center stage of the research in the field of energy storage systems from renewables., Competing Interests: The authors declare no competing financial interest.

A highly uniform porous film of MnO 2 was deposited on carbon fiber by anodic electrodeposition for the fabrication of high-performance electrodes in wearable supercapacitors (SCs) application. The effects of potentiostatic and galvanostatic electrodeposition and the deposition time were investigated. The morphology, crystalline structure, and chemical composition of the obtained fiber-shaped samples were analyzed by field-emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Raman spectroscopy, and X-ray photoelectron spectroscopy (XPS). The charge storage performance of the carbon fibers@MnO 2 composite electrode coupled to a gel-like polymeric electrolyte was investigated by cyclic voltammetry and galvanostatic charge-discharge measurements. The specific capacitance of the optimized carbon fiber@MnO 2 composite electrodes could reach up to 62 F g -1 corresponding to 23 mF cm -1 in PVA/NaCl gel-polymer electrolyte, i.e., the highest capacitance value ever reported for fiber-shaped SCs. Finally, the stability and the flexibility of the device were studied, and the results indicate exceptional capacitance retention and superior stability of the device subjected to bending even at high angles up to 150°.

This work investigates titanium dioxide nanotube arrays (TiO 2 -NTA) grown by anodic oxidation as an active material for memristive applications. In particular, metal-insulator-metal structures made of vertically oriented amorphous TiO 2 -NTA grown on titanium foil were exploited in Ti/TiO 2 -NTA/Pt devices. The deposition of a polymeric thin film between NTA and top electrodes significantly improved the stability of the devices and increased by more than double the off/on resistance ratio. The resistive switching of TiO 2 -NTA samples crystallised by thermal annealing was also studied. Such devices displayed nonlinear I-V curves characterised by a smooth rectifying behaviour, without any evident resistive switching (RS). Also in this case, the interposition of the polymeric layer enhanced the RS behaviour of TiO 2 -NTA samples, remarkably increasing the devices' off/on ratio and endurance. The rise of high resistance states can be simply related to the addition of the polymer as resistance in series, while the variation of the low resistance states is here attributed to the occurrence of surface chemical reactions between polymer functional groups and the metal oxide, which increase the charge carriers available for conduction.

TiO(2) nanotube (NT) arrays with different lengths were fabricated by anodic oxidation of Ti foil and free-standing NT membranes were detached by the metal substrate and bonded on the fluorine-doped tin oxide surface implementing an easy procedure. Morphology of the as-grown material and of the prepared photoanode was investigated by means of electron microscopy, deepening the investigation on the thermal treatment effect. Crystalline orientation and exposed surface area were studied by X-ray diffraction and Brunauer-Emmett-Teller measurements, showing suitable characteristics for the application in dye-sensitized solar cells (DSCs). DSCs were assembled employing a microfluidic housing system. The cell performances and the electron transport properties as a function of the tube length, before and after a TiCl(4) treatment, were characterized by I-V electrical measurements, incident photon-to-electron conversion efficiency, electrochemical impedance spectroscopy and open circuit voltage decay. Fitting the impedance spectra with an equivalent circuit, it was possible to obtain information on the electron diffusion properties into the TiO(2) nanotubes. A comparison with the charge transport properties evaluated in nanoparticle-based photoanodes witnesses a noteworthy increase of electron lifetime and diffusion length, yielding an overall power conversion efficiency up to 7.56%.