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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.

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

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).

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.

In this study, Li4Ti5O12 (LTO) electrodes with different types of water-soluble binders are successfully coated upon aluminum foil. Electrodes containing solely sodium alginate (SA) as a binder or a mixed PVDF/carboxymethyl cellulose (CMC) binder show the most stable performance in 1 M LiPF6 in EC/DMC 1:1 in half cell vs. Li, with respect to cycle stability over 100 cycles at 1 C. The electrodes processed with a mixture of PVDF/SA show considerable fading and slightly worse values for rate capability. Each one of the different binders used is eco-friendly, and the whole processing can be performed without the use of organic solvents. Further advantages covering the whole production and recycling process, as well as safety issues during operation, encourage deeper research in this area.

Polyvinylidenedifluoride (PVdF) and polyethyleneoxide (PEO) are blended and electrospun in order to obtain membranes suitable as Li-ion battery separators. The separators are characterized, and their properties investigated and compared with those of PVdF and commercial separators. The PVdF-PEO based separators ensure increased conductivities, greater electrolyte uptake and higher porosities than commercial polyolefines, all factors that improve cell performance. They are also safer than PVdF separators thanks to lower shutdown temperature, even if their mechanical properties are not yet comparable with those of the latter.

For the first time, a paper based enzymatic fuel cell is used as self-recharged supercapacitor. In this supercapacitive enzymatic fuel cell (SC-EFC), the supercapacitive features of the electrodes are exploited to demonstrate high power output under pulse operation. Glucose dehydrogenase-based anode and bilirubin oxidase-based cathode were assembled to a quasi-2D capillary-driven microfluidic system. Capillary flow guarantees the continuous supply of glucose, cofactor and electrolytes to the anodic enzyme and the gas-diffusional cathode design provides the passive supply of oxygen to the catalytic layer of the electrode. The paper-based cell was self-recharged under rest and discharged by high current pulses up to 4mAcm−2. The supercapacitive behavior and low equivalent series resistance of the cell permitted to achieve up to a maximum power of 0.87mWcm−2 (10.6mW) for pulses of 0.01s at 4mAcm−2. This operation mode allowed the system to achieve at least one order of magnitude higher current/power generation compared to the steady state operation.

In this work, for the first time, we demonstrate a supercapacitive microbial fuel cell which integrates the energy harvesting function of a microbial fuel cell (MFC) with the high-power operation of an internal supercapacitor. The pursued strategies are: (i) the increase of the cell voltage by the use of high potential cathodes like bilirubin oxidase (BOx) or iron-aminoantipyrine (Fe-AAPyr); (ii) the use of an additional capacitive electrode (additional electrode, AdE) which is short-circuited with the MFC cathode and coupled with the MFC anode (MFC-AdE). The high working potential of BOx cathode and the low impedances of the additional capacitive electrode and the MFC anode permitted to achieve up to 19 mW (84.4 Wm(-2), 152 Wm(-3)), the highest power value ever reported for MFCs. Exploiting the supercapacitive properties of the MFC electrodes allows the system to be simpler, cheaper and more efficient without additional electronics management added with respect to an MFC/external supercapacitor coupling. The use of the AdE makes it possible to decouple energy and power and to achieve recharge times in the order of few seconds making the system appealing for practical applications.

Power generation and storage in electronics require flexible, thin micro-electrochemical energy storage/conversion systems. Micro-supercapacitors (μSCs) with double-layer capacitance carbon electrodes are attracting much attention for their capability of delivering short power pulses with high stability over repeated charge/discharge cycling. Supersonic Cluster Beam Deposition (SCBD) is an effective strategy for the development of nanostructured, binder-free porous carbon electrodes on temperature sensitive substrates including polymers. We exploited SCBD for the development of a flexible, planar μSC featuring nanostructured carbon (ns-C) electrodes deposited on a plastic Mylar substrate and N-trimethyl-N-propyl-ammonium bis(trifluoromethanesulfonyl) imide (N 1113 TFSI) ionic liquid electrolyte. The electrochemical performance at different temperatures of the μSC which operates at 3 V above RT up to 80 °C with a capacitance density approaching 10 F cm −3 and delivering maximum specific energy and power densities of 10 mWh cm −3 and 8-10 W cm −3 with long cycling stability over 2 × 10 4 cycles is here reported and discussed.

LiNi 0.5 Mn 1.5 O 4 (LNMO) composite electrodes having the same formulation as to percentage of active material mass, binder and carbons, including reduced graphene oxide, were characterized in EC: DMC – 1M LiPF 6 by cyclic voltammetry, charge/discharge cycles and impedance spectroscopy. The results demonstrate the beneficial effect on the electrode cycling stability in increasing C-rate to 1C, in limiting the charge voltage at 4.8 V and in covering the LNMO by partially reduced graphene oxide. The paper also discusses the evaluation of lithium diffusion coefficient in LNMO from cyclic voltammetry data in regard to the discrepancies reported in literature on this matter.

Innovative separators able to improve the performance and safety of Li-ion batteries are under investigation to meet the growing demand for large-size and high energy density electrochemical cells. In this work, highly porous nanofibrous Poly(vinylidene fluoride) (PVdF) separators loaded with oxide nanoparticles were produced by electrospinning. Silicon oxide and tin oxide nanoparticles were added to PVdF and membranes were characterized by SEM-EDS and TGA. The effect of nanoparticle addition on electrolyte uptake, mechanical properties and conductivity was investigated and such properties were compared to those of a commercial separator (Celgard 2400). Results showed that a small amount of additive can significantly improve the properties of PVdF electrospun membranes and that the different nanoparticles investigated in this work have different effect on membrane performances. In particular, the addition of SiO2 increases the rate of electrolyte uptake and the toughness of the electrospun membrane, while the addition of SnO2 decreases the rate of electrolyte uptake and increases the stiffness of the electrospun membrane. When loaded with nanoparticles, PVdF membranes maintain their insulating character also at high temperature. Preliminary electrochemical results on half-cell vs Li with LiFePO4 and electrospun separators showed good cycling performance, highlighting interesting features of this technology. © The Author(s) 2015. Published by ECS. This is an open access article distributed under the terms of the Creative Commons Attribution Non-Commercial No Derivatives 4.0 License (CC BY-NC-ND, http://creativecommons.org/licenses/by-nc-nd/4.0/), which permits non-commercial reuse, distribution, and reproduction in any medium, provided the original work is not changed in any way and is properly cited. For permission for commercial reuse, please email: oa@electrochem.org. [DOI: 10.1149/2.0421506jes] All rights reserved.

The present paper focuses on a nanostructured SnCo alloy electrochemically prepared by template method in view of its use as anode material alternative to graphite in lithium-ion batteries. The fabrication of SnCo nanowire arrays was carried out by potentiostatic co-deposition of the two metals by using nanostructured anodic alumina membranes as template. Electrochemical tests on lithiation-delithiation of these SnCo electrodes in conventional organic electrolyte (EC:DMC LiPF6) at 30°C showed that their specific capacity was stable for about the first 12 cycles at a value near to the theoretical one for Li22Sn5 and, hence, progressively decayed.