Search

Na-ion batteries are emerging as convenient energy-storage devices for large-scale applications. Enhanced energy density and cycling stability are key in the optimization of functional cathode materials such as P2-type layered transition metal oxides. High operating voltage can be achieved by enabling anionic reactions, but irreversibility of O2-/O2n-/O2 evolution still limits this chance, leading to extra capacity at first cycle that is not fully recovered. Here, we dissect this intriguing oxygen redox activity in Mn-deficient NaxNi0.25Mn0.68O2 from first-principles, by analyzing the formation of oxygen vacancies and dioxygen complexes at different stages of sodiation. We identify low-energy intermediates that release molecular O2 at high voltage, and we show how to improve the overall cathode stability by partial substitution of Ni with Fe. These new atomistic insights on O2 formation mechanism set solid scientific foundations for inhibition and control of this process toward the rational design of new anionic redox-active cathode materials.

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs), chiefly for large-scale energy storage from renewables. Developing novel active materials is essential for the deployment of NIBs, especially in terms of negative electrodes that can accommodate the larger sodium ions. We focus on TiO2 anatase, which has been proposed as a promising anode material for the overall balance of performance, stability and cost. As the exposed crystal facets in different morphologies of nanostructured anatase can affect the electrochemical performances, here we report a theoretical investigation of Na+ adsorption and migration through (101), (100) and (001) surface terminations, thus explaining the different activities toward sodiation reported in the literature. Energy barriers computed by means of the CI-NEB method at the DFT+U level of theory show that the (001) surface is the most effective termination for Na+ insertion. We also provide a detailed analysis to elucidate that the energy barriers are due to structural modifications of the lattice upon sodiation. From these results we derive new design directions for the development of cheap and effective oxide-based nanostructured electrode materials for advanced NIBs.

Li-ion batteries (LIBs) are the ubiquitous technology to power portable electronics; however, for the next-generation of high-performing electrochemical energy storage systems for electric vehicles and smart grid facilities, breakthroughs are needed, particularly in the development of solid-state electrolytes, which may allow for enhanced energy density while enabling lithium metal anodes, combined with unrivalled safety and operative reliability. In this respect, here we present the successful synthesis of a glass-ceramic Li1.4Al0.4Ge0.4Ti1.4(PO4)3 NASICON-type solid-state electrolyte (SSE) through a melt-casting technique. Being grain boundaries crucial for the total ionic conductivity of SSEs, the effect of the addition of diboron trioxide (B2O3, 0.05 wt.%) to promote their liquefaction and restructuring is investigated, along with the effects on the resulting microstructures and ionic conductivities. By the thorough combination of structural-morphological and electrochemical techniques, we demonstrate that bulk materials show improved performance compared to their powder sintered counterpart, achieving remarkable ion mobility (> 0.1 mS cm–1 at –10 °C) and anodic oxidation stability (> 4.8 V vs Li+/Li). The addition of B2O3 positively affects the grain cohesion and growth, thus reducing the extension of the grain boundaries (and the related grain/grain interface resistance) and, therefore, increasing the overall ion mobility. In addition, B2O3 is seen to contrast the microcracks formation in the LAGTP system under study which, overall, shows very promising prospects as SSE for the next-generation of high-energy density, safe lithium-based batteries.

D-glucosamine is investigated as a non-toxic and sustainable carbon/nitrogen (C/N) source for the templated synthesis of nitrogen-containing CMK-8 ordered mesoporous carbons (NOMCs) conceived for selective CO2 uptake. Pyrolysis temperature is varied during nanocasting using the KIT-6 silica hard template to tailor microporosity and nitrogen inclusions. NOMCs exhibit large surface area (600e1000 m2 g-1) and excellent pore ordering. The CO2/adsorbent interaction energy is estimated by the isosteric enthalpy of adsorption (~33e40 kJ mol-1) and Henry's constants. The role of nitrogen content (~7 e12 at.%) and of each type of N-species on CO2 adsorption is studied by X-ray photoelectron spectroscopy, and CO2/N2 selectivity is attributed, being pyridinic functionalities the most effective ones. NOMCs are tested at different temperatures, gas flow compositions, reversibility, and so on; in all tested conditions, they outperform a homologous bare sucrose-derived carbon. Enhancing micropore volume allows achieving maximum adsorption capacity in pure CO2 (1.47 mmol g1 at 30 C/0.9 bar), whereas increasing surface N-content accounts for the highest selectivity in CO2/N2 mixtures (20/80 v/v) at 35 C/ 1 bar (maximum CO2 uptake 0.82 mmol g1 ). The combination of a suitable C/N precursor and the hard templating synthetic route is effective for obtaining high-performing, sustainable, and reusable selective CO2 sorbents, without any activation steps or N-doping post-treatments. © 2021 The Author(s). Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Increasing the photocurrent is one of the main objectives of the current research on aqueous photovoltaic cells, the emerging green, alternative technology in solar energy conversion devices. In such a scenario, this work deals with the thorough understanding of the electrochemical and photoelectrochemical effects of the TiCl4 treatment onto TiO2 electrodes, a well-known process for traditional dye-sensitized solar cells, and here, to our knowledge, investigated for the first time in water-based systems. From the quantitative evaluation of the photoelectrochemical parameters, it emerges that the TiCl4 treatment beneficially affects the photovoltaic parameters: it doubles the sunlight conversion efficiency values, inhibits the recombination of photogenerated electrons with oxidized redox mediator ions, and ensures stable and reproducible cell performance at the laboratory scale. (C) 2019 Elsevier Ltd. All rights reserved.

We report an innovative cross-linked composite polymer electrolyte (CPE) based on the garnet-type ceramic super Li+ ion conductor, Li7La3Zr2O12 (LLZO), that is encompassed in a supersoft poly(ethylene oxide)/tetraglyme matrix. UV-induced, facile and solvent-free cross-linking process ensures flexible and self-standing CPEs, which are nonflammable and perfectly shape-retaining under thermal/mechanical stress. The CPEs exhibit high ionic conductivity, exceeding 0.1 mS cm–1 at 20 °C, suitable for ambient and subambient temperature operation. Lab-scale lithium metal polymer cells assembled with LiFePO4-based composite cathode and the optimized CPE deliver full capacity at low current rates and outstanding specific discharge capacity of 115 mAh g–1 at 1C rate and ambient temperature. Remarkably, the lithium metal cell can run for hundreds of galvanostatic cycles (>400) with low overpotential, limited fading, and excellent Coulombic efficiency (>99%), which postulates the practical application of the newly deve...

In this paper a novel polymer-based platform is applied for the fabrication of an innovative two-electrodes self-powered device integrating energy harvesting and storage sections. A multifunctional polymeric layer, made of two poly(ethylene glycol)-based sections separated by a perfluorinated barrier, is obtained by oxygen-inhibited UV-light crosslinking procedure. For the energy harvesting section, one side of the polymeric layer is adapted to enable iodide/triiodide diffusion in a dye-sensitized solar cell (DSSC), while the other side empowers sodium/chloride ions diffusion and is used for on-board charge storage in an electrochemical double layer capacitor (EDLC). The resulting photocapacitor has a planar architecture appreciably simplified with respect to other recently proposed solutions and more easily exploitable in low power electronics. The measured photo-electrical conversion and storage total efficiency is 3.72% during photo-charge, which is a remarkable value for DSSC-EDLC harvesting-storage devices literature. The obtained high frequency discharge capability enlightens promising prospects for practical applications in low power portable electronics.

In this study, self-standing and flexible Li-ion battery negative electrodes made of interconnected two-dimensional carbonized cotton fibers are developed by using a controlled pyrolysis method, and their electrochemical performance in laboratory-scale lithium-based cells is investigated at ambient temperature. By applying this binder- and current collector-free cotton-based carbon fiber electrode, both the Li+-ion intercalation and capacity decay mechanisms are explored using conventional organic carbonate-based liquid electrolyte. The cotton-based carbon fiber electrode shows excellent cycling performance and delivers a high discharge capacity in the voltage range of 0.02 - 1.2 V. The post cycling analysis of carbon fiber using HR-TEM shows the major SEI layer components formed at the surface of the active fibers during the charge/discharge process. The same electrode is used to assemble a lab-scale Li-ion full cell with high mass loading LiFePO4-based composite electrode, which demonstrates excellent cycling stability, high Coulombic efficiency and remarkable rate capability at ambient temperature.

We perform electric double-layer gating experiments on thin films of niobium nitride. Thanks to a cross-linked polymer electrolyte system of improved efficiency, we induce surface charge densities as high as $\approx 2.8 \times 10^{15}\,\mathrm{cm}^{-2}$ in the active channel of the devices. We report a reversible modulation of the superconducting transition temperature (either positive or negative depending on the sign of the gate voltage) whose magnitude and sign are incompatible with the confinement of the perturbed superconducting state to a thin surface layer, as would be expected within a na\"ive screening model., Comment: 5 pages, 3 figures

Understanding the transport of sodium ions in ionic liquids is key to designing novel electrolyte materials for sodium-ion batteries. In this work, we combine molecular dynamics simulation and experiments to study how molecular interactions and local ordering affect relevant physico-chemical properties. Ionic transport and local solvation environments are investigated in electrolytes composed of sodium bis(fluorosulfonyl)imide, (Na[FSI]), in N,N-methylpropylpyrrolidinium bis(fluorosulfonyl)imide, [C3C1pyr][FSI], at different salt concentrations. The electrolyte systems are modelled by means of molecular dynamic simulations using a polarizable force field. We show that including polarization effects explicitly in the molecular simulations is required in order to attain a reliable description of the transport properties of sodium in the [C3C1pyr][FSI] electrolyte. The validation of the computational results upon comparison with experimental data allows us to assess the suitability of polarizable force fields in describing and interpreting the structure and dynamics of the sodium salt-ionic liquid system, which is essential to enable the application of IL-based electrolytes in novel energy-storage technologies.

Whereas the commercialization of dye-sensitized solar cells (DSSCs) is finally proceeding taking advantage of their low cost and tunable optical features, such as colour and transparency for both indoor and building-integrated applications, the corresponding aqueous counterpart is still at its infancy. As the TiO

Na-ion batteries (NIBs) are attracting widespread interest as a potentially more convenient alternative to current state-of-the-art Li-ion batteries (LIBs), chiefly for large-scale energy storage from renewables. Developing novel active materials is essential for the deployment of NIBs, especially in terms of negative electrodes that can accommodate the larger sodium ions. We focus on TiO

The need to recycle waste products, convert and reuse them for different high-value applications is a very up-to-date, utmost important topic. In this context, here we propose glycidol, a high-value product isolated from epichlorohydrin industry waste, as a starting material for the preparation of two poly(glycidol)s polymer matrices with a chemical structure mimicking that of poly(ethylene oxide), i.e. the most used polymer matrix for non-liquid battery electrolytes. The materials are characterized from the physico-chemical viewpoint, showing high thermal stability. They are then obtained in the form of ionic conducting polymer electrolytes encompassing different sodium salts and solvent mixtures. Ionic conductivity values exceeding 10−5 S cm−1 are measured in the “dry” truly solid state at 80 °C, while it approaches 6 × 10−5 S cm−1 at ambient temperature in the “wet” quasi-solid state. In addition, poly(glycidol)-based polymer matrices show reasonably wide electrochemical stability towards anodic oxidation. It envisages their possible use as separating electrolytes in secondary batteries, which is also demonstrated by preliminary charge/discharge cycling tests in lab-scale sodium cells. The present findings pave the way to a circular economy platform starting from industry wastes and ending with post-lithium storage systems.

The recycling of CO2 back into chemicals via photo-electrochemical cells represents a viable route to mitigate the global climate crisis of current days. In this paper we focus on the copper-iron delafossite oxide, CuFeO2, which has been proven to have suitable physico-chemical properties to photo-catalyze the carbon dioxide reduction to formic acid. The specific electronic and structural features that allow activating the highly stable CO2 molecule are dissected by exploiting state-of-the art first principles methods. The effects of surface oxygen vacancies as well as the different roles of copper and iron on the adsorption and the activation of carbon dioxide at the CuFeO2 most stable surface are analyzed. These results highlight the key role of oxygen defects in favoring the CO2 adsorption and in promoting the formation of a radical anion CO2 − or a carbonate-like adsorbate so providing the scientific grounds for implementing new rational design strategies and improving the performances of CuFeO2-based photoelectrodes for CO2 reduction.

Sodium-ion technology is a reliable alternative to lithium-ion for large-scale energy storage because of the abundance of sodium sources and related low cost. In this work, we report about a simple fabrication of self-standing electrodes based on electrospun carbon nanofiber (CNF) loaded with Na3V2(PO4)(3) with NASICON framework, which is a promising cathode material that has shown good electrochemical performance when its electrical conductivity is enhanced by a conductive medium. The proposed method is simple, low cost, potentially scalable to fabricate and load cathode support with active materials. The electrochemical tests confirmed the stable cycling performances and the high C-rate capability of the NVP/CNFs composites, with hundreds of cycles without major degradation of performances. Our work demonstrates that stable, self-supported, long-term performing NIB electrodes, ready to use without addition of any performance enhancer, can be obtained by using fast and cost-efficient procedures suitable to be scaled-up at an industrial level.

A green, efficient and stable solar cell based only on water and safe and cheap elements of the periodic table is proposed in this work, finally consolidating (also from a sustainability viewpoint) the concept of “artificial photosynthesis” studied for decades by the scientific community. The concept of dye-sensitized solar cells is re-proposed here with a metal-free organic dye, an iodine-based electrolyte in a 100% aqueous environment and a new cathode (cationic PEDOT) synthesized for the first time with the aim of inhibiting the repulsion between the anions of redox couples and the PEDOT:PSS matrix commonly used as the counter-electrode. This elegant setup leads to a record efficiency of 7.02%, the highest value ever obtained for a water-based solar cell and, in general, for a photovoltaic device free of both organic solvents and expensive/heavy metals., A new cationic PEDOT derivative inhibits repulsion phenomena within iodine-based electrolytes, boosting the efficiency of aqueous solar cells.

Dye-sensitized solar cells (DSSCs), as emerging photovoltaic technology, have been thoroughly and extensively investigated in the last three decades. Since their first appearance in 1991, DSSCs have gained increasing attention and have been classified as feasible alternatives to conventional photovoltaic devices due to their numerous advantages, such as cheap and simple preparation methods, the possibility of being integrated in buildings and astonishing performances under indoor and diffuse illumination conditions. Photoconversion efficiencies of up to 14% and 8% have been obtained for lab-scale devices and modules, respectively. Albeit the efforts made, these values seem arduous to be outdone, at least under simulated solar radiation. Nevertheless, recent lab-scale systems have demonstrated photoconversion efficiencies of up to 33% under indoor illumination (i.e. 1000 lux) leading to an actual Renaissance (or Revival) of these devices. It is worth mentioning that scientists in this field are developing innovative materials aiming at long-term and efficient devices, being the concept of sustainability often set apart. However, in light of effective commercialization of this technology, stability, efficiency and sustainability should be considered as the essential keywords. Nowadays, DSSCs are finding a “new way back” towards sustainability and rather a huge number of reports have focused on the preparation of green and cost-effective materials to replace the standard ones. In this scenario, the present review aims to give an overview of the most adopted strategies to enhance the sustainability of materials in classical DSSC components (e.g. sensitizer, redox couple, electrolyte and counter-electrode), including smart synthesis and deposition procedures, which currently represent utmost important topics in the scientific community.

Lithium Metal Batteries (LMB) require solid or quasi-solid electrolytes able to block dendrites formation during cell cycling. Polymer-in-ceramic nanocomposites with the ceramic fraction exceeding the one normally used as the filler (>10 ÷ 15 wt%) are among the most interesting options on the table. Here, we report on a new hybrid material encompassing brush-like TiO2 nanocrystals functionalized with low molecular weight poly(ethylene oxide) (PEO). The nanocomposite electrolyte membranes are then obtained by blending the brush-like nanocrystals with high molecular weight PEO and LiTFSI. The intrinsic chemical compatibility among the PEO moieties allows a TiO2 content as high as ∼39 wt% (90:10 w/w functionalized nanocrystals/PEO-LiTFSI), while maintaining good processability and mechanical resistance. The 50:50 w/w nanocomposite electrolyte (18.8 wt% functionalized TiO2) displays ionic conductivity of 3 × 10−4 S cm−1 at 70 °C. Stripping/plating experiments show an excellent long-term behavior even at relatively high currents of 200 μA cm−2. Upon testing in a lab-scale Li/electrolyte/LiFePO4 cell, the material delivers 130 mAh g−1 and 120 mAh g−1 after 40 and 50 cycles at 0.05 and 0.1 mA, respectively, with Coulombic efficiency exceeding 99.5%, which demonstrates the very promising prospects of these newly developed nanocomposite solid electrolyte for future development of LMBs.

Graphene is a new generation material, which finds potential and practical applications in a vast range of research areas. It has unrivalled characteristics, chiefly in terms of electronic conductivity, mechanical robustness and large surface area, which allow the attainment of outstanding performances in the material science field. Some unneglectable issues, such as the high cost of production at high quality and corresponding scarce availability in large amounts necessary for mass scale distribution, slow down graphene widespread utilization; however, in the last decade both basic academic and applied industrial materials research have achieved remarkable breakthroughs thanks to the implementation of graphene and related 1D derivatives. In this work, after briefly recalling the main characteristics of graphene, we present an extensive overview of the most recent advances in the development of the Li-ion battery anodes granted by the use of neat and engineered graphene and related 1D materials. Being far from totally exhaustive, due to the immense scientific production in the field yearly, we chiefly focus here on the role of graphene in materials modification for performance enhancement in both half and full lithium-based cells and give some insights on related promising perspectives.

In this work, the use of cobalt redox electrolytes in partly covered photoelectrochromic devices is investigated experimentally for the first time. The fabricated devices consist of a conductive glass photoanode coated with an electrochromic WO3 film of optical quality, including a mesoporous TiO2 layer (sensitized by the MK2 organic dye) that covers 20% of the device area. The liquid electrolyte is composed of 0.22 M Co(II)(bpy)3(PF6)2, 0.5 M LiClO4 and 0.5 M 4-tert-butylpyridine. A platinized conductive glass cathode completes the cell set-up. The fabricated devices are almost transparent in the bleached state with a Tlum value above 50%. They exhibit coloration speeds in the order of minutes, with a maximum contrast ratio of 2.9:1 after 21 min of illumination at 1000 W m−2 under open circuit conditions (OC), and high reversibility to fully bleached state in short circuit conditions. They provide a maximum measured power conversion efficiency of 0.28% due to limitations imposed by conflicting requirements of the photovoltaic and electrochromic elements, which is nonetheless sufficient to drive the coloration process. Since only the reduced specie Co2+ is present, initial illumination under OC for 3 min at 1000 W m−2 is necessary, prior to measurements, to oxidize Co2+ to Co3+ through the dye regeneration process in the electrolyte. The higher recombination losses of the Co2+/3+ redox shuttle compared to I−/I3−, which lead to a considerable reduction in coloration depth 20 days post fabrication due to loss of photoelectrons at the WO3/electrolyte interface, are suppressed by the use of a 35 nm thick ZnS barrier deposited on top of WO3. Remarkably, it results in a stabilized contrast ratio of 1.5:1, 23 days post fabrication. In addition, the color coordinates of the present devices resemble those of typical electrochromics: they exhibit blue coloration, as a result of the lack of the absorbing iodine in the electrolyte that produces a green tint.

The rational design of single-ion polymer electrolytes emerges as a primary strategy for enhancing the performance of lithium ion batteries. With the aim to increase ionic conductivity, four novel ionic liquid monomers were designed and synthesized in high purity. Such monomers differ from the previously reported systems by (1) the presence of a long and flexible spacer between the methacrylate group and chemically bonded anion or (2) by a long perfluorinated side chain. The investigation of their free radical copolymerization with poly(ethylene glycol) methyl ether methacrylate (PEGM) allowed to identify the impact of thei copolymer composition on thermal and ion conducting properties. The copolymer based on lithium 3-[4-(2-(methacryloyloxy)ethoxy)-4-oxobutanoyl)oxy) propylsulfonyl]-1-(trifluoromethylsulfonyl)imide showed the highest ionic conductivity (1.9 × 10−6 and 2 × 10−5 S cm−1 at 25 and 70 °C, respectively) at [EO]/[Li] = 61 ratio, along with a wide electrochemical stability (4.2 V vs. Li+/Li) and high lithium-ion transference number (0.91). The prepared copoly(ionic liquid)s (coPILs) were further applied for the assembly of Li/coPIL/LiFePO4 lithium-metal cells, which were capable to reversibly operate at 70 °C delivering relatively high specific capacity (up to 115 mAh g−1) at medium C/15 current rate.

In this work we present a very simple preparation procedure of a poly(ethylene oxide) (PEO)-based crosslinked polymer electrolyte (XPE) for application in sodium-ion batteries (NIBs). The polymer electrolyte, containing NaClO 4 as Na + source, is prepared by rapid, energy saving, solvent-free photopolymerization technique, in a single step. Thermal, mechanical, morphological and electrochemical properties of the resulting XPE are thoroughly investigated. The highly ionic conducting (>1 mS cm −1 at 25 °C) polymer electrolyte is used in a lab-scale sodium cell with nanostructured TiO 2 working electrode. The obtained results in terms of ambient temperature cycling behaviour (stable specific capacity of about 250 mAh g −1 at 0.1 mA cm −2 and overall remarkable stability, for a quasi-solid state Na polymer cell, upon very long term cycling exceeding 1000 reversible cycles at 0.5 mA cm −2 corresponding to > 5000 h of continuous operation) demonstrate the promising prospects of this novel XPE to be implemented in the next-generation NIBs conceived for large-scale energy storage systems, such as those connected to photovoltaic and wind factories.

Single-ion conducting polymer electrolytes represent the ideal solution to reduce concentration polarization in lithium metal batteries (LMBs). This paper reports on the synthesis and characterization of single-ion ABA triblock copolymer electrolytes comprising PEO and poly(lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide) blocks, poly(LiMTFSI). Block copolymers are prepared by reversible addition - fragmentation chain transfer polymerization, showing low glass transition temperature (−55 to 7 °C) and degree of crystallinity (51–0%). Comparatively high values of ionic conductivity are obtained (up to ≈ 10 −4 S cm −1 at 70 °C), combined with a lithium-ion transference number close to unity ( t L i + ≈ 0.91) and a 4 V electrochemical stability window. In addition to these promising features, solid polymer electrolytes are successfully tested in lithium metal cells at 70 °C providing long lifetime up to 300 cycles, and stable charge/discharge cycling at C/2 (≈100 mAh g −1 ).

Single-ion polymer electrolytes are expected to play an important role in the development of next-generation lithium metal batteries. In this paper, the synthesis and characterization of single-ion conducting polyurethanes (SIPUs) based on PEG and a specifically designed ionic liquid monomer (bis-MPTFSI) is presented. Exploiting the flexible chemistry of polyurethanes, it was possible to tailor the composition and chemical structure of SIPE, obtaining both segmented and crosslinked lithium ion-conductive (σ = 10 −8 −10 −4 S cm −1 ) and free-standing films with the lithium transference number close to unity. Finally, the performances of gel polymer electrolytes based on SIPUs for lithium metal batteries operating at room temperature were investigated (80 cycles at C/10 with nearly 100% efficiency). To the best of our knowledge, these SIPUs represent one of the first examples of polyurethane-based poly(ionic liquid)s for application in the field of battery science.

Due to their inherent safety, low cost, and structural stability, TiO2 nanostructures represent a suitable choice as anode materials in sodium-ion batteries. In the recent years, various hypotheses have been proposed regarding the actual mechanism of the reversible insertion of sodium ions in the TiO2 structure, and previous reports are often controversial in this respect. Interestingly, when tested as binder- and conducting additive-free electrodes in laboratory-scale sodium cells, amorphous and crystalline (anatase) TiO2 nanotubular arrays obtained by simple anodic oxidation exhibit peculiar and intrinsically different electrochemical responses. In particular, after the initial electrochemical activation, anatase TiO2 shows excellent rate capability and very stable long-term cycling performance with larger specific capacities, and thus a clearly superior response compared with the amorphous counterpart. To obtain deeper insight, the present materials are thoroughly characterized by scanning electron microscopy and ex situ X-ray diffraction, and the insertion of sodium ions in the TiO2 bulk phases is systematically modeled by density functional theory calculations. The present results may contribute to the development of more systematic screening approaches to identify suitable active materials for highly efficient sodium-based energy storage systems.

Gallium oxide nanorods prepared by template-free synthesis are reported for the first time as safe and durable anode material for lithium- and sodium-ion batteries. The ambient temperature electrochemical response of the nanorods, tested by cyclic voltammetry and constant-current reversible cycling, is highly satisfying in terms of remarkable stability and capacity retention upon long-term operation (400 cycles), even at high current densities. The newly proposed application of gallium oxide nanorods as electrode material is notable also because this material can preserve the electrical pathway without the need of any "buffer matrix" to compensate for the expansion upon lithium or sodium reversible storage. The highly promising electrochemical performance is attributed to the high aspect ratio and high surface area that stem from the nanorod morphology and which can lead to short diffusion path and fast kinetics of both cations (Li+ or Na+) and electrons. (C) 2017 Elsevier Ltd. All rights reserved.

Natural cellulose fibres are proposed as promising components for bioderived photoanodes and polymer electrolytes in dye-sensitized solar cells (DSSCs). In particular, TiO2-laden paper foils, prepared by simple papermaking, can be applied to several substrates (conductive glass or plastics) instead of the high-temperature sintered traditional commercial pastes. In addition, nanoscale microfibrillated cellulose is used as reinforcing filler in acrylate/methacrylate-based thermo-set polymer electrolyte membranes prepared by means of fast, low-cost and green UV-induced free-radical photopolymerization. The laboratory-scale quasi-solid state paper-DSSCs assembled with cellulose-based electrodes and electrolytes guarantee sunlight conversion efficiencies as high as 3.55 and 5.20% at simulated light intensities of 1 and 0.2 sun, respectively, along with an excellent efficiency retention of 96% after 1000 h of accelerated aging test. The simple, low cost and green approach here specifically developed opens up intriguing prospects in the design of bio-inspired energy conversion devices showing high performance, outstanding durability and truly sustainable characteristics.