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The high abundance and low cost of aluminum and sulfur make the Al–S battery an attractive combination. However, significant improvements in performance are required, and increasing the thickness and sulfur content of the sulfur electrodes is critical for the development of batteries with competitive specific energies. This work concerns the development of sulfur electrodes with the highest sulfur content (60 wt %) reported to date for an Al–S battery system and a systematic study of the effect of the sulfur electrode thickness on battery performance. If low‐cost electrolytes made from acetamide or urea are used, slow mass transport of the electrolyte species is identified as the main cause of the poor sulfur utilization when the electrode thickness is decreased, whereas complete sulfur utilization is achieved with a less viscous ionic liquid. In addition, the analysis of very thin electrodes reveals the occurrence of degradation reactions in the low‐cost electrolytes. The new analysis method is ideal for evaluating the stability and mass transport limitations of novel electrolytes for Al–S batteries., Thick and thicker! The thickness of the cathode and viscosity of the electrolyte affect the rate of transport of electrolyte species inside the porous sulfur electrode in Al–S batteries and cause poor sulfur utilization in deep eutectic solvents, whereas complete sulfur utilization is achieved with a less viscous ionic liquid. In addition, the analysis of the effect of cathode thickness on battery performance and the electrochemistry of carbon additives provides evidence of the degradation of deep eutectic solvents in Al–S batteries.

The Lithium–Sulfur battery is considered to be one of the main candidates for the “post-lithium-ion” battery generation, because of its high theoretical specific capacity and inherently low cost. The role of the electrolyte is particularly important in this system and remarkable battery performances have been reported by tuning the amount of salt in the electrolyte. To further understand the reasons for such improvements we chose the lithium bis(trifluoromethanesulfonyl)imide in 1,3-dioxolane electrolyte as a model salt-solvent system for a systematic study of conductivity and viscosity over a wide range of concentration from 10-5 up to 5 molal. The experimental results, discussed and interpreted with reference to the theory of electrolyte conductance, lead to the conclusion that triple ions formation is responsible for the highest molal conductivity values before reaching the maximum at 1.25 molal. At higher concentrations, the molal conductivity drops quickly due to a rapid increase in viscosity and the salt–solvent system can be treated as a diluted form of molten salt.

Casein from bovine milk is evaluated in this work as binding agent for electrochemical double layer capacitors (EDLCs) electrodes. It is demonstrated that casein provides excellent adhesion strength to the current collector (1187 kPa compared to 51 kPa achieved with PVdF), thus leading to mechanically stable electrodes. At the same time, it offers high thermal stability (above 200 °C) and electrochemical stability in organic electrolytes. Apparently though, the casein-based electrodes offer lower electronic conductivity than those based on other state-of-the-art binders, which can limit the rate performance of the resulting EDLC. In the attempt of improving the electrochemical performance, it is found that the application of a pressing step can solve this issue, leading to excellent rate capability (up to 84% capacitance retention at 50 mA cm −2 ) and cycling stability (96.8% after 10,000 cycles at 10 mA cm −2 ) in both PC- and ACN-based electrolytes. Although the adhesive power casein is known since ancient times, this report presents the first proof of concept of its employment in electrochemical power sources.

In this manuscript we report about the realization and testing of a high-voltage electrochemical double layer capacitor (EDLC) prototype (IES prototype), which has been assembled using innovative electrode and electrolyte components. The IES prototype displays a nominal capacitance of 4 F, a maximum voltage of 3.2 V and its maximal energy and power are in the order of 37 Wh kg −1 and 65 kW kg −1 , respectively. Furthermore, it also displays good cycling stability, high capacitance retention after 80 h float test and acceptable self-discharge. Taking into account substantial improvements of the cell design and assembly procedure, the performance of the IES prototype indicates that the components utilized in this device might be suitable alternatives to the state-of-the-art materials used in high energy EDLCs.

Electrochemical impedance spectroscopy (EIS) is a widely applied non-destructive method of characterisation of Li-ion batteries. Despite its ease of application, there are inherent challenges in ensuring the quality and reproducibility of the measurement, as well as reliable interpretation and validation of impedance data. Here, we present a focus review summarising best metrological practice in the application of EIS to commercial Li-ion cells. State-of-the-art methods of EIS interpretation and validation are also reported and examined to highlight the benefits and drawbacks of the technique.

International audience

The scientific community is continuously committed to the search for new high energy electrochemical storage devices. In this regard, lithium metal batteries, due to their very high electrochemical energy storage capacity, appear to be a highly appealing choice. Unfortunately, the use of lithium metal as the anode may lead to some safety hazards due to its uneven deposition upon charging, resulting in dendrite growth and eventual shorting of the battery. This issue may be successfully addressed by using intrinsically safer electrolytes capable of establishing a physical barrier at the electrode interface. The most promising candidates are solid electrolytes, either polymeric or inorganic. The main purpose of this review is to describe the present status of worldwide research on these electrolyte materials together with a critical discussion of their transport properties and compatibility with metallic lithium, hoping to provide some general guidelines for the development of innovative and safe lithium metal batteries.

Tin oxide (SnO) is considered one of the most promising metal oxides for utilization as anode material in sodium ion batteries (SIBs), because of its ease of synthesis, high specific gravimetric capacity, and satisfactory cycling performance. However, to aim at practical applications, the Coulombic efficiency during cycling needs to be further improved, which requires a deeper knowledge of its working mechanism. Here, a microflower-shaped SnO material is synthesized by means of an ultrafast ionic liquid-assisted microwave method. The as-prepared SnO anode active material exhibits excellent cycling performance, good Coulombic efficiency as well as a large capacity delivered at low potential, which is fundamental to maximize the energy output of SIBs. These overall merits were never reported before for pure SnO anodes (i.e., not in a composite with, for example, graphene). Additionally, by combining ex situ XRD and XPS, it is clearly demonstrated for the first time that the Sn-Na alloy, which is formed during the initial sodium sodiation, desodiates in two successive but fully separated steps. Totally different from the previous report, the pristine SnO phase is not regenerated upon desodiation up to 3 V vs Na/Na

Used as a bare active material or component in hybrids, graphene has been the subject of numerous studies in recent years. Indeed, from the first report that appeared in late July 2008, almost 1600 papers were published as of the end 2015 that investigated the properties of graphene as an anode material for lithium-ion batteries. Although an impressive amount of data has been collected, a real advance in the field still seems to be missing. In this framework, attention is focused on the most prominent research efforts in this field with the aim of identifying the causes of such relentless progression through an insightful and critical evaluation of the lithium-ion storage performances (i.e., 1st cycle irreversible capacity, specific gravimetric and volumetric capacities, average delithiation voltage profile, rate capability and stability upon cycling). The "graphene fever" has certainly provided a number of fundamental studies unveiling the electrochemical properties of this "wonder" material. However, analysis of the published literature also highlights a loss of focus from the final application. Hype-driven claims, not fully appropriate metrics, and negligence of key parameters are probably some of the factors still hindering the application of graphene in commercial batteries.

We unravel the role of flake dimensionality on the lithiation/de-lithiation processes and electrochemical performance of anodes based on few-(FLG) and multi-layer graphene (MLG) flakes prepared by liquid phase exfoliation (LPE) of pristine graphite. The flakes are sorted by lateral size (from 380 to 75 nm) and thickness from 20 (MLG) to 2 nm (FLG) exploiting a sedimentation-based separation in centrifugal field and, finally, deposited onto Cu disks for the realization of four binder-free anodes. The electrochemical results show that decreasing lateral size and thickness leads to an increase of the initial specific capacity from ≈590 to ≈1270mAhg −1 . However, an increasing irreversible capacity is also associated to the reduction of flakes’ size. We find, in addition, that the preferential Li ions storage by adsorption rather than intercalation in small lateral size (