Renewable energy production is inherently intermittent, necessitating large-scale implementation to enhance energy storage capacity, which presently accounts for less than 1% of global electrical energy production. The pursuit of greener, more affordable, and safer rechargeable batteries is currently recognized as strategically important in advancing electrochemical energy storage technology, addressing environmental concerns and establishing a sustainable energy economy. Li-ion batteries (LIBs) and Na-ion batteries (NIBs) play a crucial role as energy storage devices for electric vehicles and smart grids. It is widely recognized that a detailed analysis of an electrode reveals that each component (active material, conductive carbon, current collector, and binder) contributes to the overall battery performance. It has been demonstrated that the binder, despite its relatively low content, typically a few percent of the total composition, plays a decisive role in determining the electrode performance, which is noteworthy considering its chemical and electrochemical inactivity. In addition, the transformation from liquid- to gel-/quasi-solid or fully solid-state architectures is expected to improve safety by using low-volatile, non-flammable materials and energy density of energy storage devices by enabling the use of lithium metal anodes, particularly if constraints of low ionic conductivity, low cation transport properties and stringent processing conditions are overcome [1].

In this context, here an overview is offered of the recent developments in our laboratories on the development of innovative solutions including recycled or biosourced polymer binders/electrolytes towards the development of sustainable, safe, high-performing post-lithium batteries. These include the possibility of repurposing in batteries the recycled polyvinyl butyral (PVB) from post-consume laminated glasses (from automotive and construction) that cannot be reused in glasses because of degraded optical properties. Three strategies were pursued: using recycled PVB as binder in the electrode composition, transforming it into a membrane to be used as electrolyte separator [2], and utilizing it in advanced solid-state batteries. In the case of PVB as binder, we investigated the electrochemical and structural properties of polymer blends of PVB with standard binders, as polyacrylic acid (PAA) and poly(vinylidene fluoride) (PVDF), demonstrating its effective use in the development of various electrodes, including hard carbon (HC) anodes, and high-energy cathodes (NMC and NVP) showing full capacities even at high C-rates and stable long-term operation at ambient temperature, which pave the way to the development of more sustainable binders/separators from waste products for next-generation, sustainable energy storage. Regarding solid-state batteries, the incorporation of recycled PVB into polyethylene oxide (PEO)-based solid polymer electrolytes was investigated to address both performance and sustainability challenges. This approach enables the design of composite polymer electrolytes with improved mechanical strength, thermal stability, and electrochemical performance while promoting the use of recycled materials to reduce environmental impact.

Overall, in all cases, preliminary results are highly encouraging and pave the way to the development of more sustainable separators and binders from waste products for safe, low-cost energy storage devices.

Rechargeable aqueous Zinc (Zn) batteries are one of the emerging beyond lithium-ion batteries that could fulfil the requirements of cost-effective, safe, and reliable large-scale storage systems.^[1,2] Zn metal is abundant, globally available, and non-toxic, with a promising theoretical capacity of 820 mA h/g.^[3] However, aqueous Zn batteries encounter several degradations upon cycling due to the dendrite formation, poor Coulombic efficiency and hydrogen evolution reaction.^[4] Additionally, separator technology remains a major bottleneck, with no efficient commercial options. Commonly used glass-fiber and cellulose filters are not optimized for Zn anodes, leading to poor compatibility. Thus, the development of advanced electrolytes and separators is crucial for enhancing aqueous Zn battery performance.

In this study, we have successfully engineered both a high-performing aqueous eutectic electrolyte and a novel chitin-based separator. Our electrolyte formulation is based on the combination of a strongly chaotropic cation, Gua, and a strong kosmotropic anion, Ac, to precisely tailor their strong and weak coordination with water, respectively. This strategy results in a weakly solvated electrolyte with improved ion transport properties alongside stabilisation of the Zn metal anode. On the other hand, the nanochitin-based separator, achieved through surface modification of chitin fibre with amine and carboxylic groups, showcases outstanding mechanical properties and compatibility with Zn anodes. Notably, this separator/electrolyte significantly enhances Zn cycling stability, demonstrating a remarkable increase from a mere 200 cycles with conventional glass-fibre and cellulose separators to 1000 cycles. This combined approach presents a compelling strategy for the advancement of high-voltage aqueous Zn metal batteries, marking a significant step forward in battery technology.

The rapid progress in energy storage technologies demands innovative solutions to challenges related to sustainability, cost, and performance. Aqueous zinc-based energy storage systems, such as zinc metal batteries (AZMBs) and zinc-hybrid capacitors (ZHCs), offer promising possibilities due to their inherent safety, cost-effectiveness, and scalability.[1] Nonetheless, complications like hydrogen evolution reactions, dendritic growth, and water-induced parasitic reactions are major obstacles to be overcome before these technologies can be practically employed on a large scale. The following abstract summarizes findings from three new central studies that place MCEs at the forefront in driving a new generation of research breakthroughs to overcome these challenges and improve performance in aqueous zinc systems.

The first study investigates an advanced MCE containing a combination of Zn(TFSI)₂, LiTFSI, and polyethylene glycol (PEG400) to improve the performance of Zn//LFP hybrid batteries.[2] By confining water molecules and reducing free water activity, the optimized MCE enhances the reversibility of Zn plating/stripping and significantly improves long-term cyclability. The Zn//LFP battery, in turn, showed quite high capacities of 120 mAh g⁻¹ with excellent stability-65% capacity retention after 200 cycles-whereas the self-discharge rate is reduced and parasitic reactions are suppressed compared to conventional electrolytes. These confirm the effectiveness of MCEs for solutions of major anode and cathode problems in AZMBs.

The second investigation is concerned with a Zn//V₂O₅ battery, which works out a newly developed MCE, using Zn(TFSI)₂ as the main salt.[3] The electrolyte formulation in this work enhances ionic conductivity, hence boosting ion transport properties to further ensure superior rate capability and decent cycle stability. It obtains excellent performance metrics of the Zn//V₂O₅ system, such as 78% capacity retention after 1000 cycles and an impressive reduction in self-discharge. Mitigation of free water activity hence improved the stability window, which assured reversible Zn plating/stripping and placed the MCE as a versatile strategy toward the advancement of AZMBs for practical applications.

Another study investigates the use of PEGDME-based MCE in ZHCs as means to solve such Zn anode problems but without sacrificing its practicability.[4] The advanced MCE obtained had a widened electrochemical stability window of up to 2.7 V, which reduced the water activity and hence improved anti-corrosion properties that enabled superior performance in Zn//Cu and Zn//Zn symmetric cells. The hybrid system of Zn/MCE/AC achieved energy density at 138 Wh/kg, perfect capacitance of 281 F/g, and superlative cyclability, with capacity retained up to 100% after 19,100 cycles. These results really underline the big capability of MCEs in providing high-power, long-life energy storage solutions.

Collectively, these works highlight how MCEs will be game-changing in overcoming fundamental challenges in aqueous-based zinc energy storage systems. By taking advantage of novel electrolyte chemistries to suppress parasitic reactions, enhance ionic transport, and stabilize electrode interfaces, MCEs will provide a route toward safe, efficient, and sustainable energy storage systems. This work presents an important milestone toward successful practice application of AZMBs and ZHCs and in particular provides for impactful solutions to global challenges in energy storage.

Metal-air batteries are considered a viable alternative to conventional Li-ion batteries as their air-breathing electrode configuration results in higher theoretical capacity and energy density. Moreover, zinc-air batteries (ZABs) take advantage of low cost, environmental-friendliness and safety, since they work in aqueous electrolyte [1].

However, the main issue with ZABs is the limited performance due to sluggish kinetics of oxygen reduction reaction (ORR) and oxygen evolution reaction (OER), resulting in high overpotentials and low round-trip efficiency. The implementation of electrocatalysts helps to accelerate reaction kinetics and make ZABs more competitive for electrochemical storage applications.

Among a variety of electro-catalytical materials (transition metal oxides, heteroatom-doped carbon, metal organic frameworks, etc.) manganese dioxide (MnO₂) is one of the most promising for ORR/OER [2].

In this scenario, we optimized nanostructured MnO₂-based Gas Diffusion Electrodes (MnO₂-GDEs) using different types of MnO₂ micro/nanocrystals obtained by hydrothermal synthesis varying precursors and additives (such as CTAB or ionic liquids, e.g. BMIM-BF₄). The use of additives allowed us to show a transformation in MnO₂ morphology and crystallographic structure passing from beta-MnO₂ nanorods (with a diameter of 200 nm) to alpha-MnO₂ nanowires (with a diameter of 20 nm) by exploiting the capping agent capacity of additives during chemical synthesis [3].

In the end, we implemented MnO₂-GDEs in laboratory-scale Zn-air batteries to investigate the relationship between MnO₂ micro-nanostructure and their electrochemical performance in galvanostatic discharge/charge cycles and with electrochemical impedance spectroscopy in a full-device configuration.

Multivalent (Mg, Ca, Al) metal anodes offer promising gravimetric and volumetric capacities and are a promising option for future high energy density batteries based on sustainable materials. However, their practical application is severely limited by the difficulty of ion insertion, slow diffusion and the presence of side reactions during electrochemical operation. Organic cathodes, with their relatively soft and adaptable structures, offer an alternative to overcome the limitations of inorganic hosts.[1]

In our work we combine organic compounds with different multivalent non-nucleophilic electrolytes. We started our work with polymers from anthraquinone class, which fit well into the electrochemical stability window of multivalent electrolytes due to their moderate working potential. The long-term cycling stability in combination with insoluble organic polymers and suitable non-nucleophilic electrolytes reaches several hundred cycles. However, there are still some challenges in terms of capacity utilisation and cycling stability that need to be addressed. We aim to improve our understanding of these challenges by analysing the electrochemical mechanism in detail using electrochemical impedance analysis and ex-situ electron microscopy, which reveal limitations in the transport of multivalent ions within the active materials.[2] At the same time, we also focus on the development of active compounds with higher energy density, either through increased capacity or redox potential.[3]

The organic electrode materials (OEM) are emerging as a promising alternative to develop greener and sustainable battery technologies. However, significant improvements are still required in their cycling stability, rate capability and energy density. This can only be achieved through a fundamental understanding of the electrochemistry at molecular level establishing the structure-properties relationships. To contribute to this end, we are developing methodologies based on evolutionary algorithms (EA) and artificial neural networks (ANN) at interplay with density functional theory (DFT) based calculations. The EA has initially been employed to predict the structure and electrochemistry of a set of dicarboxylates. In a second stage, we have developed a wider database of organic materials for energy applications that contains information about molecular geometries and high-level features extracted from DFT calculations. Based on this database, we have developed a machine learning approach to predict the redox potentials by giving only chemical species and molecular structures, completely by-passing the computer-demanding DFT calculations. A number of learning algorithms based on ANN have been investigated along with different molecular representations. Here we have also included a layer to predict redox-stable compounds. This machinery has been employed to screen a large organic materials library leading to the discovery of novel cathode materials [1,2], which is actually one of the bottlenecks on the development of organic batteries. The computational materials design platform developed here has the potential of significantly contribute to accelerate the discovery of organic electrode materials with superior properties.

Nowadays, lithium-ion batteries (LIBs) remain the most widely used and manufactured energy storage technology due to their high energy density, long cycle life, and versatility across various applications, including consumer electronics, electric vehicles, and renewable energy systems. However, LIBs face challenges due to limited lithium reserves, toxic cathode materials like cobalt, and unethical mining practices in developing countries, causing environmental and social concerns. Sodium-ion batteries (SIBs) are considered highly promising to replace lithium in storing electrochemical energy from renewable sources and enabling long-range electric vehicles, as sodium is more abundant and widely available. Indeed, sodium-ion batteries face challenges due to the limited availability of suitable cathode materials capable of efficiently hosting sodium ions. Among the promising candidates, covalent organic frameworks (COFs), a class of crystalline porous organic polymers, stand out for their tunable structure, high surface area, and potential to enable reversible sodium-ion storage through redox-active sites.[1] COFs are suitable as electrodes for SIBs due to their insolubility in electrolyte, the possibility to introduce numerous redox-active sites and tunable porosity to facilitate ion diffusion.[2],[3] Herein, we will present the electrochemical performance of an anthraquinone-based COF cathode material in sodium batteries, encompassing cyclic voltammetry, long cycling stability, and analysis of the sodium-ion diffusion mechanism within the material.

Keywords: Sodium-ion batteries, covalent organic framework, organic batteries, electroactive porous materials.

Developing high-performance electrochemical energy storage systems is one of the most prominent pathways to reach the “net zero emission” goal. For that reason, the demand on batteries has increased exponentially in recent years. Indeed, the conventional batteries based on inorganic materials successfully replied to this request so far. On the other hand, since the R&D efforts have been very intense on such compounds either in academic or industrial level, theoretical limits are almost reached for those conventional systems. Moreover, it is predicted that the increased requirement on such inorganic materials (mostly based on lithium derivatives) may lead scarcity of their raw compounds. It is equally important to mention here that most of these inorganic materials are toxic, unsafe, and unsustainable.[1] Therefore, moving out of the comfort zone to discover novel abundant battery components, which can easily be reached without any geographical limitations, is intriguing. In this context, organic electrode materials (OEMs) are interesting alternatives.

Appearance of OEMs was nearly at the same time with their inorganic competitors. Recently, discovery of molecules carrying redox active side groups (e.g., carbonyls) made OEMs highly interesting in the field.[2] Although their leaching during operations due to their high solubility is always highlighted as a major drawback, forming their polymers neutralized this short-coming.[1] Additionally, going one step further from the traditional 1D polymers to high dimensional (hyper)crosslinked (porous) polymeric backbones make the functional moieties more reachable by the counter ions thanks to the high accessible surface area provided by the empty voids (i.e. pores).[3]

Here we present phenothiazine (PTz)-based hypercrosslinked polymers as high performance and low-cost p-type OEMs, which are rare[4] when compared to the n-types. The syntheses were carried out via a facile method, Friedel-Crafts alkylation (i.e. knitting polymerization),[5,6] in between the low-cost commercially available compounds either to form homopolymer of PTz or its random co-polymers with benzene. The increased benzene portion in the reaction resulted in higher crosslinking, therefore, higher accessible surface areas (BET surface areas from 29 to 586 m² g^-1). Although introduction of the redox inactive benzene reduced the theoretical capacity (from 112 to 77 mAh/g), such addition yielded OEMs with enhanced practicability, including increased durability, operationality in higher C-rates, propensity to increase both polymer content and its mass loading in the electrode. In conclusion, the possibility of such trade-off via macromolecular engineering can be a guide to produce advanced materials with high performance and practicability not only for application in batteries but also in complementary electrochemical techniques.

The stability of electrode materials in aqueous electrolytes is crucial for the longevity and efficiency of energy storage systems, especially under conditions that promote water electrolysis. This study examines the self-discharge characteristics of polyimide (PI)-based electrodes in aqueous environments. By systematically examining key factors such as electrolyte type, concentration, operational parameters, and environmental conditions, we aim to identify the underlying causes and elucidate the mechanisms driving self-discharge in organic polymer electrodes. Our findings reveal that water reduction at the electrode not only contributes to reversible self-discharge but also significantly influences irreversible capacity loss. Comparison with nonaqueous systems highlight the pronounced sensitivity of organic electrodes to even minimal water content, which exacerbates degradation. These observations underscore the urgent need for strategies to mitigate both reversible and irreversible degradation processes in aqueous battery systems. Our presentation will discuss these phenomena and potential mitigation strategies in detail, offering new perspectives on enhancing the stability and performance of organic electrodes in aqueous conditions.

In the first part of the talk, I will introduce recently developed methodology for elucidation of the most important electrochemical performance parameters for high energy density battery materials, including electrode/electrolyte interphase conducitivity and cationic transference numbers from electrochemical impedance spectroscopy, and bulk ion diffusion coefficients in electrolytes and electrodes from galvanostatic polarization. Here, detailed elucidation of spectra and equivalent circuit developement allows for extraction of charge transfer resistances and compext time/temperature behavior. In the second part of the talk, I will focus on application of such methodology on most promissing materials, such as Li/Na/K/Mg/Al metals in contact with contemporary liquid electrolytes, concentrated liquid (e.g. containing triple ions) and polymer electrolytes (above 40 wt% of salt), sustainable sodium cathodes and hard carbon anodes. In the case of metals, the findings show diversity of materials chemistry, with relevance of existence and potential corrosion of native oxide films, as well as dendrites.  Finally, I will give an outlook on how to potentially develop future sustainable high performance battery materials.

Lithium-sulfur (Li-S) batteries are among the most promising of the ‘beyond Li-ion’ battery technologies, due to their high theoretical gravimetric capacity (1675 mAh g^-1_S) and energy density (2500 Wh kg^-1_S), which far exceed those of Li-ion batteries (LIBs). Li-S batteries benefit from the use of sulfur as an earth-abundant, low-cost and geographically widespread positive-electrode material. These systems exploit the reversible 16-electron interconversion of S₈ and Li₂S at the positive electrode, coupled with the plating and stripping of Li at the negative electrode.

Despite the promise of the Li-S battery, practical cell performance is often limited due to poor interconversion of S₈ and Li₂S, which is exacerbated at higher rates of discharge and charge. While there are many reasons for this performance limitation, it is generally accepted the battery requires a catalyst at the positive electrode to achieve high energy efficiency and rates. Despite this, the exact role of the catalyst in the Li-S battery remains elusive and the nature of the rate limiting steps is unknown. Here we will discuss the fundamental reaction routes within the lithium sulphur battery. Using a combination of analytical electrochemical techniques we have identify those steps which are rate limiting during discharge of the cell. In addition, we will discuss the development of molecular catalysts able to drive the interconversion of S₈ and Li₂S. Two types of molecular catalysts will be described; 1) simple redox shuttles and 2) homogeneous catalysts able to trigger disproportionation reactions. A variety of electrochemical and analytical techniques have been utilised to assess the role of the molecular catalysts in sulfur redox chemistry. Using galvanostatic cycling,  we are able to demonstrate the impact of these molecular catalysts in cells, which display enhanced cycling performance. Finally, we present an alternative statistical approach to cell data analysis.

Ammonium-ion batteries have emerged as a promising energy storage technology for certain applications, offering advantages such as environmental friendliness, cost efficiency, and abundant resource availability. However, the side reactions originating from electrolytes, such as the water decomposition, and host material dissolution preclude their practical applications. Unlike the traditional metal-based aqueous batteries, the idea of “ultrahigh concentrated electrolyte” is not feasible due to the strong hydrolysis reactions of ammonium ions at high concentration.

Our group has been developing innovative strategies including hydrogen bond engineering, electrolyte engineering, and electrode engineering to overcome the challenges faced by aqueous ammonium-ion batteries. The role of hydrogen bond chemistry in stabilizing ammonium ions and improving ionic transport is particularly important, as it affects both electrode–electrolyte interfaces and bulk electrolyte performance.

In this work, we introduce sucrose molecules as electrolyte additive into the ammonium trifluoromethanesulfonate electrolyte. The quaternary hydrogen bond network is formed among cations (NH₄⁺), anions (OTf-), solvents (H₂O) and additives (C₁₂H₂₂O₁₁). Such unique hydrogen bond network can inhibit the water decomposition. More interesting, we found that the weak hydrogen bond coordination of NH₄⁺ ions and sucrose molecules allows faster ion diffusion in the bulk electrolytes. This is a new discovery which is very different from  metallic charger carriers used in aqueous batteries.

Utilizing such designed electrolytes, the assembled ammonium full battery shows remarkable cycling stability of 2000 cycles at 20 °C and 10000 cycles at −20 °C, respectively.

We believe this work presents a new electrolyte modulating strategy for advancing the practical potential of aqueous ammonium ion batteries. 

The growing demand for portable devices and electric vehicles has significantly accelerated the development of lithium-ion batteries, driving innovation towards achieving higher energy density, greater power output, and enhanced safety.[1] Currently, graphite anodes, with a theoretical capacity of 372 mAh g⁻¹, are widely used but remain a limiting factor. In contrast, lithium metal anodes offer a much higher theoretical capacity of 3860 mAh g⁻¹, making them promising candidates for next-generation lithium batteries that prioritize high energy density and extended cycle life.[2] However, challenges such as the irreversible loss of lithium due to dendrite formation, whisker growth, and the generation of "dead lithium" pose significant safety risks.

To address these issues, anode-less lithium battery design has emerged as a promising alternative, offered the highest achievable energy density while mitigating safety concerns.

In this study, an ultrathin layer was deposited onto a copper foil using physic-chemical methods, enabling its use as negative electrode in a quasi-anode-less lithium metal battery configuration. Electrochemical testing in a coin cell setup demonstrated notable performance improvements compared to traditional anode-less systems. Detailed morphological and compositional analyses of the thin layer, functioning as a solid electrolyte interphase, were conducted using SEM and XPS techniques. These findings lay a robust foundation for further research, aiming to enhance stability and extend the lifespan of lithium metal batteries through practical design optimizations.[3]

The European Union has established a policy to achieve climate neutrality by 2050. Therefore, one of the strategies is to increase renewable energy sources drastically and, in turn, develop efficient energy storage devices and batteries of particular interest. For large-scale stationary applications, sustainability and cost-effective batteries are more attractive. In this context, lithium-ion batteries (LIBs) are not the most interesting battery chemistry due to their mass production comes with environmental and social challenges, which will even increase more as the market expands. Indeed, lithium-based technology production involves several critical raw materials, where suppliers concentrate in third countries and conflict zones, and expensive elements (i.e., natural graphite, cobalt, lithium, nickel, etc.) [1,2]. In this scenario, the development of alternative energy storage devices based on sustainable and cost-effective materials is crucial [3].

Sodium-ion batteries (NIBs) are postulated as a complementary technology to lithium-ion batteries (LIBs) for stationary applications and light electromobility due to their lower cost and sustainability, as they are made of non-critical raw materials [3]. Recently, several companies have been presented with potential applications of SIB to bolster their commercialization. For example, CATL, one of the biggest battery manufacturers in the world, recently announced on production of SIBs. Potassium-ion batteries (KIBs) might be another attractive alternative due to they keep the sustainability and cost aspects, with several advantages over NIBs. Potassium, as sodium, is abundant and widely distributed on the Earth’s crust and ocean, while it exhibits lower reduction potential than Na (i.e., -2.71 V and −2.93 V vs. SHE for Na and K, respectively). Moreover, K ions diffuse faster in liquid than Na ions -and Li ions, leading to higher energy density and higher power density than NIBs. The Group 1 start-up has recently released a KIB prototype, and they announced a large-scale production of KIBs by 2027, demonstrating that KIBs could be a reality. Unfortunately, the current performance of KIBs is inferior to that of both LIBs and NIBs. Therefore, further advances are necessary to enhance the viability of KIBs [4]. Thus, this work will be focused on the comparison of Na- and K-based electroactive materials (electrode and/or electrolyte) and identify the key parameters affecting the electrochemical properties to achieve high-performing NIBs and KIBs.

Na-ion battery technology, developed as a cost-efficient and sustainable alternative to the widely deployed Li-ion batteries (LIBs), has experienced unprecedented growth over the past years. Such rapid development greatly benefited from the earlier advancements in materials chemistry for LIBs, and, therefore, the general understanding of materials could be easily adopted by Na-ion chemistry. However, the use of conventional anode materials from LIBs is challenging, as the most common examples from LIBs (graphite and silicon) do not perform well in Na-ion batteries (NIBs). For that reason, hard carbon was adopted as state-of-the-art and the most common anode material for NIBs. Further improvement of Na storage capacity of anodes required alternative materials, such as alloying materials; however, their cycling stability represents a major drawback for their efficient implementation in NIBs.

The materials operating under conversion/alloying mechanism (where the alloying reaction is triggered by the conversion occurring during the first sodiation) represent a promising class of materials, which can deliver high Na storage capacities without sacrifice of cycling stability. However, the complexity of their operating mechanism(s) severely impedes their development. This presentation will be focused on development and implementation of operando methodologies for characterization of the operation mechanism of these materials and correlating the mechanisms with the electrochemical performances. The challenges associated with the design and characterization of these anode materials will be highlighted.

Global population growth and the expansion of electric vehicles have led to a surge in energy demand, stimulating the search for alternatives to fossil fuels and accelerating the transition to renewable energy sources. In this context, metal-sulfur batteries (Li-S or Na-S) have become a promising area of research. Sodium batteries are characterized by their lower cost and abundance compared to lithium, making them an attractive candidate for large-scale applications. However, Na-S batteries face significant hurdles, including sluggish reaction kinetics, the insulating nature of sulfur, and the dissolution of polysulfides resulting in the well-documented "shuttle effect" [1].
To overcome these obstacles, advanced materials for Na-S batteries are being investigated, with sulfurized polyacrylonitrile (SPAN) showing remarkable potential. This carbon-based polymer has favorable electrochemical properties. Through simple and efficient synthesis methods, sulfur is covalently bonded to the polyacrylonitrile (PAN) backbone, eliminating the formation of long-chain polysulfides. This innovation largely mitigates or even eliminates the shuttle effect, resulting in improved stability and capacity in Na-S cells [2,3].
In this study, the textural and morphological properties of SPAN were extensively analyzed after a facile synthesis. Its electrochemical performance was tested using CR2032-type Na-S button cells, and it demonstrated exceptional long-term stability over more than a thousand charge-discharge cycles. Furthermore, it achieved impressive specific capacity values at high charge and discharge rates, surpassing many conventional materials.
This work introduces SPAN as a promising cathode material for Na-S batteries. Its combination of low cost, high sustainability, and scalability positions it as a strong candidate for next-generation energy storage solutions, addressing global energy demands while contributing to environmentally friendly technologies

Due to abundant raw materials, low costs and promising high reversible specific capacities, hard carbons (HCs) are a common choice for commercially manufactured anodes in sodium-ion batteries (SIBs). Despite their potential and extensive use, the storage mechanism is still under debate. The non-stoichiometric adsorption mechanism also means that the search for an upper limit for the reversible capacity is ongoing. There is a strong requirement for synthetic anodes that enable a better understanding of the theoretical capacity associated with HC-anodes. We have developed core-shell carbon anodes consisting of a highly porous carbon core and (almost) non-porous shell. Thus, the reversible capacity can be deconvoluted from irreversible capacity losses, arising from the formation of the solid electrolyte interphase (SEI). Moreover, the porosity of the carbon-core can be linked to the reversible capacities gained.

A range of microporous activated carbons were coated via an optimized  chemical vapour deposition technique.[1][2] These materials were characterised using a range of techniques including powder x-ray diffraction, small angle x-ray diffraction (SAXS), gas physisorption (N₂, CO₂) measurements and electrochemical characterisation at coin cell level.  

After coating, the material showed a significant reduction in detectable surface area (up to a factor of 192x) by N₂-physisorption. The tailor-made shell allows the stable cycling of a carbon anode vs metallic Na-electrode in coin cells at room temperature. For the best performing material, the reversible capacity increased from 139 ± 2 mAhg^-1 to 396 ± 2 mAhg^-1 while irreversible capacity is decreased from 636 ± 3 mAhg^-1 to 89 ± 3 mAhg^-1 (see Figure 1). After initial stabilization, a CE of 99% was achieved. The coating technique was usefully applied to a range of materials.

The successful formation of core-shell structures with high capacities enables separation of the storage mechanism from SEI-formation. In turn a proposed calculation to rank the contributions of surface adsorption and pore filling capacity can be confirmed. The materials also create the opportunity to conduct a range of operando experiments (e.g., SAXS) that can shed further light on the sodium storage mechanism.

Potassium-ion batteries (KIBs) are emerging as a promising option for large-scale energy storage. Compared to Li-ion batteries, KIBs offer advantages such as the abundance of potassium resources and the potential for cobalt-free cathode materials, leading to lower costs. The fast diffusion kinetics of K⁺ ions in liquid electrolytes may also enable faster charge and discharge processes. Key electrode materials for KIBs include Prussian blue analogues (PBAs), vanadium fluorophosphates such as KVPO₄F, and transition metal oxides at the cathode, while graphite and hard carbon are the
most promising anode materials.
This study highlights the use of electrochemical characterization, along with a range of experimental techniques such as X-ray diffraction, Mössbauer spectroscopy, and Raman spectroscopy, supported by density functional theory (DFT) calculations, to analyze the electronic structure and electrochemical mechanisms of these materials for KIBs.
On the anode side, research shows that the mechanism of K⁺ intercalation into graphite in glyme-based electrolytes changes from co-intercalation to intercalation with increased electrolyte salt concentration, influenced primarily by K⁺ ion solvation rather than solid electrolyte interphase (SEI) formation. Graphite experiences a significant volume expansion (around 60%) during K⁺ intercalation, while hard carbon shows limited volume change, leading to superior performance in terms of initial coulombic efficiencies (ICEs) and specific capacities. This can be attributed to the uniform morphology and
higher interplanar distance of hard carbon structures.
On the cathode side, systems such as Mn-Fe PBAs and potassium manganese oxides like K₃MnO₄ were tested. While these materials are cost-effective and non-toxic, they suffer from Mn dissolution at extreme oxidation states, limiting stable cycling. Similarly, the instability at high potentials of KVPO₄F restricts its electrochemical capacity.
These insights, enabled by advanced characterization techniques, especially under operando conditions, underscore the need for a detailed understanding of electrochemical properties and cycling mechanisms to develop new, effective materials for KIBs

The concept of concentrated aqueous solutions, referred as water-in-salt electrolytes (WISEs),¹ brought back recently the interest in aqueous batteries. These electrolytes can be described as few water molecules surrounded by cations and anions. The limited amount of free water molecules, the particular interfaces created,² as well as the change of the solvation structure strongly modify the solutions behavior. Consequently, the electrochemical stability window is largely extended up to more than 3 V. Multiple strategies have been implemented to extend further the stability window by occupying the water molecules, with the addition of a co-salt (bi-salt electrolyte)³ or the presence of a molecular crowding agent such as a polymer.⁴ These strategies strongly impact the organization of the water molecules in solution. Similarly, the kosmotropic or chaotropic character of the salt anion⁵ affects the water network, with the chaotropic anions being more efficient in disturbing the water molecules. Yet, the importance of such strategies on the long-term reactivity of aqueous batteries,⁶ particularly on the challenging limitation of the hydrogen evolution reaction (HER) at the cathodic side, has yet to be fully demonstrated.

In this context, we performed a screening of the gas production in full magnesium cells as a function of the electrolyte’s nature: imide,⁷ acetate or perchlorate-based electrolytes, bi-salt electrolytes and polymer-based electrolytes. In particular, we focused on H₂ production, used as a universal criterion to assess the relevance of the solutions considered.

At low molalities, we found that the production of H₂ follows the kosmo/chaotropic classification of the anions. However, at the highest molalities (or lowest water-to-anion ratios), a similar trend for the production of H₂ is observed, whatever the electrolyte considered. While the nature of the anion has a major influence on the solution’s organization, ultimately the H₂ production and reactivity seems only guided by the quantity of water in solution.

Li-ion battery technology is nowadays the selected technology for energy storage of electric vehicles and portable electronics. However, its sustainability and scalability are questionable due to the use of rare elements, such as Co, Ni and Li. Alternatives to the current Li-ion battery technology are under development, such as Li- S, Li-O₂, beyond-Li technologies (like Na-ion, Mg and Al batteries) and various organic-based batteries. [1,2]

Redox polymers that can be reversibly oxidized and reduced are gaining much attention as sustainable organic electrode materials to replace the aboved mentioned inorganic scarce materials. The main advantages are that redox polymers can be chemically tuned and biobased, thus enabling materials for new battery technologies such as paper batteries, organic redox flow batteries, polymer−air batteries, or flexible organic batteries. In this talk, we will present the synthesis and characterization of redox polymers having radical groups and a family of bio-based polyhydroxyanthraquinones. Their application as organic electrode materials in Li-Organic batteries will be also presented. [3,4]

The global demand for electrochemical energy storage has been drastically growing and the projections are a challenge for the entire value-chain of lithium ionlithium-ion batteries.^[1] The related challenges in feedstock supply and cost fluctuations waswere driving the research and development on sodium-ion batteries, a drop-in technology using much more abundant raw materials.^[2] First commercial SIB cells from HAKADI® Shenzhen Zhonghuajia Technology Co.,Ltd. were available in September 2023 for private users in Europe. The objective of this study is to safely disassemble commercially available sodium-ion batteries (SIBs) and analyse the cell components—cathode, anode, separator, and electrolyte—in terms of their material composition. In this work, two types of SIB cells from different manufacturers were disassembled, examined, and compared. Similar approaches have been pursued by Waldman et al. and Sauer et al.^[3,4] However, different cell types are investigated in the current study.

Given the varied nature of the cell components, a comprehensive characterisation requires multiple analytical techniques. After successfully opening the cells, the electrodes were initially measured for dimensions, weight, and thickness. Scanning Electron Microscopy (SEM) was employed to investigate the particle morphology and size of both the cathode and anode. Additionally, Energy Dispersive X-Ray Spectroscopy (EDX) was used to determine the elemental composition of the active materials of anode and cathode. The specific surface area of the active material powders was also analysed.

Thermogravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC) enabled the determination of the thermal properties of the components. TGA allows for the assignment of characteristic weight losses to specific components, thereby enabling quantitative statements on material composition. DSC, in turn, allows for the identification of characteristic phase transitions associated with specific materials.

The analysis revealed very similar compositions at the material level for both cell types. Only in the electrolyte a difference was observed: one cell type contained three organic carbonates, while the other contained four organic carbonates. Intriguingly, the SEM data for the cathode demonstrated notable differences in particle size and morphology, despite both cathode active materials being composed of the same transition metal oxide, i.e., NaNi_0.33Fe_0.33Mn_0.33O₂.

The two cell types (SIB_A and SIB_B) displayed significant differences in cycling stability. SIB_B could be charged and discharged stably over several hundred cycles, while SIB_A lost nearly 10% of its initial capacity after approximately 20 cycles. These differences may stem from cell design, such as insufficient electrode contact or uneven coatings. Alternatively, the discrepancies in cycle stability could arise from material-level differences, such as electrolyte composition. The data obtained so far suggest that the differing cell performance observed may be linked to variations in particle size and morphology of the cathode active materials. These findings provide important insights into which material compositions, particle sizes, and morphologies may be advantageous for the further development of specific SIB cell components.

The global publishing landscape has been evolving in recent years, with a notable shift towards openness and accessibility. This has been driving scientists to more openly sharing their discoveries, and undeniably accelerating towards an Open Access world. The Open Access movement has been grounded in key shared declarations and supported by several policy changes at institutional, national, and international levels. However, its influence expands beyond policy. The Open Access movement plays a vital role in addressing the needs of researchers and society by ensuring that knowledge is accessible to all.

In this publishing workshop, we will provide an overview of the Open Science movement and its origins; we will discuss the motivations behind the Open Access movement, highlighting its benefits, both to scientists and the community. Additionally, we will learn about the differences between green, bronze, gold and diamond Open Access, and discuss how they differ in terms of accessibility, costs, and publishing requirements. Finally, we will present the publisher's (Wiley) approach to Open Access, including an overview of our waiver program and our transformational agreements, which aim to make Open Access publishing more accessible.