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Biopolymers emerged in recent years as a promising alternative for a more sustainable manufacturing of electrochemical energy storage systems. In fact, for environmentally friendly aqueous systems, fluorinated polymers are usually adopted. For this reason, substituting these polymers with water processable binders could improve the overall environmental impact of the device. In this study, a low – cost and environmentally friendly modification of chitosan binder for self-standing activated carbon electrodes operating in Na ion, aqueous electrochemical double layer capacitors is reported and discussed.

The ever-increasing demand for renewable energy storage has led to the development of many energy storage systems, such as redox flow batteries (RFBs), including vanadium, iron-chromium, and the copper redox flow battery (CuRFB). A multitude of materials and electrolytes have been investigated to improve the performance of the CuRFB using an in-house manufactured cell. Using carbon ink coatings for the negative electrode and modern ion exchange membranes (IEMs), this version of the CuRFB was improved to current efficiencies above 95% with high voltage efficiencies of up to 81%, thereby improving energy efficiency by nearly 9% over the previous state of the art at 20 mA cm-2. Additionally, the operating time of the CuRFB was significantly extended over 210 h of operation (50 cycles), 32% of the capacity remaining, without maintenance. Finally, stability of the new system with modern IEMs was proven by operation for over 1200 h operation, with over 300 charge and discharge cycles performed.(c) 2022 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/).

Carbon felts are often used aselectrode materialsfor variousredox flow batteries(RFBs), and for optimal performance it is often required for them to be subjected to extended thermal treatment processes (25–30h). However, the Cu(II)/Cu(I)redox coupleemployed in the copper RFB, at thepositive electrodeis significantly different when compared to the vanadium alternative. For this reason, the effect and duration of thermal treatment of the carbon felt on the performance of the copper-based RFB has to be determined. Both polyacrylonitrile and rayon carbon felts were subjected to thermal treatment for 6 and 25h at 400°C. The treated carbon felts were subsequently analysed usingthermogravimetric analysis, resistivity determination, scanning electron microscopy, X-ray photoelectron spectroscopy, andRaman spectroscopy. Additionally, the effect of the thermal treatment was also determined using electrochemical testing and in a redox flow cell.

Lithium titanium oxide (Li4Ti5O12, LTO) is an attractive negative electrode for the development of safe—next-generation—lithium-ion batteries (LIBs). LTO can find specific applications complementary to existing alternatives for LIBs thanks to its good rate capability at high C-rates, fast lithium intercalation, and high cycling stability. Furthermore, LIBs featuring LTO electrodes are inherently safer owing to the LTO’s operating potential of 1.55 V vs. Li+/Li where the commonly used organic-based electrolytes are thermodynamically stable. Herein, we report the combined use of water-soluble sodium alginate (SA) binder and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI)-tetraglyme (1m-T) electrolyte and we demonstrate the improvement of the electrochemical performance of LTO-based electrodes with respect to those operating in conventional electrolyte 1M LiPF6-ethylene carbonate: dimethyl carbonate (LP30). We also tackle the analysis of the impact of combining the binder/electrolyte on the long-term cycling performance of LTO electrodes featuring SA or conventional polyvinylidene fluoride (PVdF) as binders. Therefore, to assess the impact of the combination of binder/electrolyte on performance, we performed post-mortem characterization by ex situ synchrotron diffraction experiments of LTO electrodes after cycling in LP30 and 1m-T electrolytes.

The increasing concentration of CO2 in the atmosphere is the leading cause of the greenhouse gas effect. Carbon capture and storage is an important topic to develop sustainable technologies. Molten salt CO2 capture and electrochemical transformation represent a suitable process to produce various carbon products, such as carbon nanofibers, carbon nanotubes, graphite, and graphene. The employment of graphitic anode materials for Li-ion batteries coming from CO2 capture is ideal for increasing battery sustainability. Moreover, the addition of transition metal oxides represents a suitable strategy for new negative electrodes because conversion reactions lead to high specific capacities. Among them, manganese has gained attention due to its multiple valence states and numerous possible crystalline structures. In the present work, a MnOx-graphitic carbon composite obtained by electrolysis of CO(2)via molten Li2CO3 is characterized and used to prepare a negative electrode for LIBs with an environmentally sustainable aqueous process.

Basic studies on concentrated solutions are becoming more and more important due to the practical industrial and geological applications. The use in redox flow batteries is one of the most important applications of these solutions. Specifically, in this paper we investigated high-concentrated copper chloro-complexes solutions with different additives. The concentration of ligands and additives affects the physicochemical and electrochemical properties of 2 M solutions of Cu(I) and Cu(II). Solutions with calcium chloride and HCl as Cl−source were investigated with Cu:Cl ratios of 1:5 and 1:7, the 1:5 Cu:Cl ratio being the best performing. The substitution of calcium chloride with ammonium chloride increased the conductivity. However, while the effect on the positive electrode process was not very evident, the reversibility of the copper deposition–stripping process was greatly improved. Orthophosphoric acid could be a viable additive to decrease the complexation of calcium with chloride anions and to improve the stability of Cu(II) chloro-complexes. Absorption spectroscopy demonstrated that phosphate ions do not coordinate copper(II) but lead to a shift in the distribution of copper chloro-complexes toward more coordinated species. Electrochemically, the increased availability of chloride anions in solution stabilized the Cu(II)-rich solution and led to increased reversibility of the Cu(II)/Cu(I) redox process.

Rheological properties of electrode slurries have been intensively studied for manifold different combinations of active materials and binders. Standardly, solvent-based systems are under use, but a trend towards water-based electrode manufacturing is becoming more and more important. The different solvent is beneficial in terms of sustainability and process safety but is also accompanied by some disadvantages such as extraction of residual humidity and a higher complexity concerning slurry stability. Li4Ti5O12 (LTO) active material provides good long-term stability and can be processed in aqueous solutions. Combining the LTO active material with sodium alginate (SA) as a promising biobased polymer binder reveals good electrochemical properties but suffers from bad slurry stability. In this work, we present a comprehensive rheological study on material interactions in anode slurries consisting of LTO and SA, based on a complex interaction of differentially sized materials. The use of two different surfactants—namely, an anionic and non-ionic one, to enhance slurry stability, compared with surfactant-free slurry.

This is the peer reviewed version of the following article: Correlating Structure and Properties of Super-concentrated Electrolyte Solutions: 17O NMR and Electrochemical Characterization, Irene Ruggeri, Andrea La Monaca, Francesca De Giorgio, Francesca Soavi, Catia Arbizzani, Vittorio Berbenni, Chiara Ferrara, Piercarlo Mustarelli, ChemElectroChem 2019, 6, 4002–4009, which has been published in final form at https://doi.org/10.1002/celc.201900829. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions. This article may not be enhanced, enriched or otherwise transformed into a derivative work, without express permission from Wiley or by statutory rights under applicable legislation. Copyright notices must not be removed, obscured or modified. The article must be linked to Wiley’s version of record on Wiley Online Library and any embedding, framing or otherwise making available the article or pages thereof by third parties from platforms, services and websites other than Wiley Online Library must be prohibited. &nbsp

Ceramic composite separator is more competitive than traditional polyolefin separator in the field of power supply for superior thermal stability and wettability of liquid electrolyte. In this study, we develop a two-steps method that modifies SiO2 with acrylamide (AM) by grafting process and prepare a functional SiO2 composite separator (PE/SiO2-AM). This kind of composite separator exhibits similar size-shrinkage (8.8%) to that of PE/ SiO2 composite separator at the tested temperature, lower than 18.1% of bare PE separator, and is electrochemically stable below 4.5 V (vs. Li/Li+). In addition, the Li-symmetric cells employing PE/SiO2-AM composite separator have the lowest overpotential and an improved lithium-ion transference number of 0.44. It is demonstrated from DFT calculation that the electron-rich species of imide group is able to uniformly disperse lithium-ion flux at the interface of electrolyte/lithium anode, and contributes to lithium-ion transport process. After assembling the LiCoO2/Li half cells, the cell with PE/SiO2-AM composite separator displays better cycle performance and higher discharge capacity when compared with other separators. Therefore, functional ceramic separator would be more attractive for next-generation lithium metal battery with high energy density.

A copper current collector is treated by electrolytic deposition of copper dendrites at the surface of the foil. This treatment results in a more structured surface leading to an improved contact between the electrode materials and the current collector. The contact to the electrode material particles of different sizes is investigated. Active materials of submicron size exhibit a drastically reduced internal resistance and a clearly improved C-rate capability. BET surface area measurement and calculation of roughness factor resulted in the finding of dendritic copper foil to provide an 8-fold larger surface area compared to the untreated foil. A comprehensive electrochemical impedance spectroscopy study is conducted for elucidation of electrochemical utilisation of the surface area increase. As a result, both fitting parameters for capacitance and surface resistance correspond to a similar normalization shift, indicating a clear improvement in the electro-active interface area.

The adhesion between electrode and separator is a key feature in cell assembly. Nafion&trade, coated separators for water-processed LiNi0.5Mn1.5O4 (LNMO) electrodes are here proposed as an alternative to the polyolefin separators. Specifically, polyolefin separators are modified with Nafion&trade, solutions and their adhesion to high-potential LNMO electrodes is investigated. The physicochemical properties of the Nafion&trade, coated separator and its electrochemical performance in Li/LNMO cells are discussed and compared to those obtained with polyolefin Celgard&reg, (Charlotte, NC, USA) PP2075 separator. Improved adhesion and cycling stability, which could be further enhanced by a mild lamination process, were demonstrated with a thin layer of Nafion&trade, (0.1 mg cm&minus, 2).

The term supercapacitor (or ultracapacitor) is used to indicate an electrochemical capacitor capable of storing charge through a capacitive process occurring in the electrical double layer formed at the interface between an electronic conductor (i.e., the electrode) and an electrolytic solution (e.g., non-aqueous electrolyte). The increasing demand for improved electrochemical energy storage systems continually boosts research efforts toward new materials, configurations and production processes, both for batteries and supercapacitors. The development of hybrid devices (e.g., where one electrode stores charge through a faradaic process and the other through a non-faradaic process) has also exploited progress in both the battery and supercapacitor fields. However, not all investigated materials are promising or industry-relevant, contrary to the claims in many research works. For example, complications related to the upscaling of lab-scale experiments hamper the exploitation at industrial scale. For these reasons, it is essential to define the best-practice methods to obtain reasonable predictions for supercapacitor materials and device testing. Also, many battery electrode materials are explored as supercapacitor electrode materials. However, not all battery materials can be considered as candidate electrode materials for hybrid devices. Only those materials with a suitable crystal structure for high rate capability and good cycling stability are appropriate.

Lithium/sulfur batteries are one of the most promising technologies for the next-generation batteries. However, this technology suffers from several problems mainly related to the instability of metallic lithium and to the polysulfides (PS) shuttle. An approach to address such issues is the design of new separators or the modification of existing commercial ones. The use of hybrid membranes is here proposed to improve the performance of Li metal anode and sulfur cathode. Composite separators are obtained by electrospinning or drop-casting a polymer solution of polyvinylidenefluoride (PVdF) containing graphene oxide (GO) on a polyolefin commercial Celgard 2300 separator. This is the first time that a thin layer of electrospun PVdF/GO composite is applied to a polyolefin separator for the use in Li metal-based batteries. We demonstrate that electrospinning is an effective method to obtain a thin polymer layer of PVdF/GO. The electrospun layer improves the wettability of the separator; it is beneficial to the growth of “soft” dendrite on Li anode and has a positive effect on the PS shuttle process. The casted layer featuring a higher GO content is also effective in increasing the separator wettability, although with a minor effect on Li interphase.

A new equipment for in situ electrochemical dilatometry is designed and validated by studying the volumetric changes of a model electrode. The contactless measurement system permit to not influence the dilation of the sample during the tests. In addition, different forces can be applied in a selected range. Graphite is selected as model electrode and electrochemical tests in different electrolytes are carried out under different applied forces. The results of the electrodilatometric tests on graphite in EC:DMC- and in PC-based electrolyte reveal not only lithium insertion/deinsertion process, but also the presence of simultaneous phenomena like solvent evaporation, SEI formation and gas evolution. The latter has been detected by applying different forces that affect the gas uptake and release from porous separator. Controlled hydrogen evolution experiments were carried out at different applied forces in order to assess the gassing detection ability of the dilatometer. We demonstrate that with this new equipment it is possible, from thickness variation, to collect information on processes of different nature. Specifically, different applied forces emphasized gas evolution, which is a worth studying phenomenon for increasing battery safety.