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Low‐temperature zinc batteries (LT‐ZIBs) based on aqueous electrolytes show great promise for practical applications owing to their natural resource abundance and low cost. However, they suffer from sluggish kinetics with elevated energy barriers due to the dissociation of bulky Zn(H2O)62+ solvation structure and free Zn2+ diffusion, resulting in unsatisfactory lifespan and performance. Herein, dissimilar to solvation shell tuning or layer spacing enlargement engineering, delocalized electrons in cathode through constructing intrinsic defect engineering is proposed to achieve a rapid electrocatalytic desolvation to obtain free Zn2+ for insertion/extraction. As revealed by density functional theory calculations and interfacial spectroscopic characterizations, the intrinsic delocalized electron distribution propels the Zn(H2O)62+ dissociation, forming a reversible interphase and facilitating Zn2+ diffusion across the electrolyte/cathode interface. The as‐fabricated oxygen defect‐rich V2O5 on hierarchical porous carbon (ODVO@HPC) electrode exhibits high capacity robustness from 25 to −20°C. Operating at −20°C, the ODVO@HPC delivers 191 mAh g−1 at 50 A g−1 and lasts for 50 000 cycles at 10 A g−1, significantly enhancing the power density and lifespan under low‐temperature environments in comparison to previous reports. Even with areal mass loading of ~13 mg cm−2, both coin cells and pouch batteries maintain excellent stability and areal capacities, realizing practical high‐performance LT‐ZIBs. [ABSTRACT FROM AUTHOR]

Cost‐effective and zero‐carbon‐emission seasonal/annual energy storage is highly required to achieve the Zero Emission Scenario (ZES) by 2050. The combination of Al production via inert‐anode smelting and Al conversion to electricity via Al−air batteries is a potential option. Although playing an important role in this approach, Al−air batteries, however, suffer from limited specific energy and inefficient collection of the discharge product. Herein, an important progress in addressing these issues is summarized, emphasizing the importance of non‐material, but rather process‐related aspects. First, a recently reported approach allowing controllable collection of discharge product and electrolyte regeneration is presented. Next, the importance of cell design in addressing the obstacles of Al−air batteries is emphasized. Subsequently, the impact of operational parameters on improving electrochemical performance of Al−air batteries is summarized. Last, a perspective on future research directions is proposed. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc–metal batteries (AZBs) are a promising complimentary technology to the existing lithium‐ion batteries and the re‐emerging lithium–metal batteries to satisfy the increasing demands on energy storage. Despite considerable progress achieved in the past years, the fundamental understanding of the solid‐electrolyte interphase (SEI) formation and how its composition influences the SEI properties are limited. This review highlights the functionalities of anion‐tuned SEI on the reversibility of zinc–metal anode, with a specific emphasis on new structural insights obtained through advanced characterizations and computational techniques. Recent efforts in terms of key variables that govern the interfacial behaviors to improve the long‐term stability of zinc anode, i.e., Coulombic efficiency, plating morphology, dendrite formation, and side‐reactions, are comprehensively reviewed. Lastly, the remaining challenges and future perspectives are presented, providing insights into the rational design of practical high‐performance AZBs. [ABSTRACT FROM AUTHOR]

Lithium metal batteries (LMBs) have the potential to be the next‐generation rechargeable batteries due to the high theoretical specific capacity and the lowest redox potential of lithium metal. However, the practical application of LMBs is hindered by challenges such as the uncontrolled growth of lithium dendrites, unstable solid electrolyte interphase (SEI), and excessive volume change of Li metal. To solve these issues, the design of high‐performance lithium metal anodes (LMAs) with various 3D structures is critical. Targeting at realizing the "bottom–up" Li deposition to fully utilize the 3D architecture, in recent years, strategies such as gradient host materials construction, magnetic field modulation, SEI component design, and so on have attracted intensive attention. This review begins with a fundamental discussion of the Li nucleation and deposition mechanism. The recent advances in the aspects of construction strategies and modification methods that enable the "bottom–up" Li deposition within advanced 3D host materials, with a particular emphasize on their design principles are comprehensively overviewed. Finally, future challenges and perspectives on the design of advanced hosts toward practical LMAs are proposed. [ABSTRACT FROM AUTHOR]

The demand for lithium‐ion batteries (LIBs) is driven largely by their use in electric vehicles, which is projected to increase dramatically in the future. This great success, however, urgently calls for the efficient recycling of LIBs at the end of their life. Herein, we describe a froth flotation‐based process to recycle graphite—the predominant active material for the negative electrode—from spent LIBs and investigate its reuse in newly assembled LIBs. It has been found that the structure and morphology of the recycled graphite are essentially unchanged compared to pristine commercial anode‐grade graphite, and despite some minor impurities from the recycling process, the recycled graphite provides a remarkable reversible specific capacity of more than 350 mAh g−1. Even more importantly, newly assembled graphite‖NMC532 cells show excellent cycling stability with a capacity retention of 80% after 1000 cycles, that is, comparable to the performance of reference full cells comprising pristine commercial graphite. [ABSTRACT FROM AUTHOR]

Aluminum−sulfur (Al−S) batteries are promising energy storage devices due to their high theoretical capacity, low cost, and high safety. However, the high viscosity and inferior ion transport of conventionally used ionic liquid electrolytes (ILEs) limit the kinetics of Al−S batteries, especially at sub‐zero temperatures. Herein, locally concentrated ionic liquid electrolytes (LCILE) formed via diluting the ILEs with non‐solvating 1,2‐difluorobenzene (dFBn) co‐solvent are proposed for wide‐temperature‐range Al−S batteries. The addition of dFBn effectively promotes the fluidity and ionic conductivity without affecting the AlCl4−/Al2Cl7− equilibrium, which preserves the reversible stripping/plating of aluminum and further promotes the overall kinetics of Al−S batteries. As a result, Al−S cells employing the LCILE exhibit higher specific capacity, better cyclability, and lower polarization with respect to the neat ILE in a wide temperature range from −20 to 40 °C. For instance, Al−S batteries employing the LCILE sustain a remarkable capacity of 507 mAh g−1 after 300 cycles at 20 °C, while only 229 mAh g−1 is delivered with the dFBn‐free electrolyte under the same condition. This work demonstrates the favorable use of LCILEs for wide‐temperature Al−S batteries. [ABSTRACT FROM AUTHOR]

Investigating Na‐ion battery (SIB) materials is complicated by the absence of a well‐performing (reference) electrode material since sodium metal cannot be considered as a quasi‐reference electrode. Taking advantage of the activity of both Ni and Mn, herein, the P2‐type and Mn‐rich Na0.6Ni0.22Al0.11Mn0.66O2 (NAM) material, known to be an excellent positive electrode, is investigated as a negative electrode. To prove NAM stability as both positive and negative electrode, symmetric cells have been assembled without pre‐sodiation, which showed a reversible capacity of 73 mA h g−1 and a remarkable capacity retention of 82.6 % after 500 cycles. The outstanding cycling performance is ascribed to the high stability of the active material at both the highest and lowest Na‐ion storage plateaus and the rather limited electrolyte decomposition and solid‐electrolyte‐interphase (SEI) formation occurring. The long‐term stability of NAM at both electrodes enables its use as a "reference" electrode for the investigation of other positive and negative electrode materials for SIBs, resembling the role played by lithium titanate (LTO) and lithium iron phosphate (LFP) in LIBs. [ABSTRACT FROM AUTHOR]

While solid‐state batteries (SSBs) comprising poly(ethylene oxide) (PEO) based electrolytes are successfully commercialized already for operation at elevated temperature, the selection of the cathode active material (CAM) has so far been limited to LiFePO4. When using high‐voltage CAMs such as LiNi1‐x‐yCoxMnyO2 (NCM), the cells experience fast capacity fading – the cause of which is not consistently understood in literature. In this study, electrochemical impedance spectroscopy measurements in a three‐electrode setup are applied to confirm that the NCM|PEO interface is indeed the Achilles' heel in PEO‐based SSBs at high voltages. In this regard, the interfacial stability on the cathode side depends not only on the upper cut‐off voltage, but also on the molecular weight of PEO, strongly affecting the cell performance. Scanning electron microscopy images of the cathodes after cycling suggest that at high voltages interfacial degradation leads to fragmentation of the polymer backbone and to a decrease in viscosity of the solid polymer electrolyte. Overall, the results help to understand the detrimental processes occurring in PEO‐based SSBs in combination with high‐voltage cathodes. [ABSTRACT FROM AUTHOR]

Low Coulombic efficiency and significant capacity decay resulting from an unstable solid electrolyte interphase (SEI) and dendritic growth pose challenges to the practical application of lithium‐metal batteries. In this study, a highly efficient protection layer induced by octaphenylsilsesquioxane (OPS) with LiFSI salt is investigated. The OPS exhibits a strong adsorption energy with lithium, its multi‐site gradient adsorption ability enables the simultaneous capture of 8 Li+ and the uniform regulation of Li ion flux. Moreover, the mechanical strength and electronic insulation of the OPS layer induces Li deposition under the protection layer and effectively inhibits lithium dendrite growth. Such a protection layer contributes to the stable and dendrite‐free performance of a lithium‐metal battery employing LiNi0.8Co0.1Mn0.1O2 (NCM811) as a cathode and an ultrathin OPS‐protected lithium foil (20 µm) as the anode. A remarkable capacity retention of 91.4% is achieved after 300 cycles at 1C. The OPS‐protected Li anodes and NCM811 are also tested in combination with a Li1.5Al0.5Ge1.5(PO4)3 solid electrolyte, showing extended cyclability up to 300 cycles with an average Coulombic efficiency of 99.58% and capacity retention of 85.7%. [ABSTRACT FROM AUTHOR]

Na‐ion batteries based on abundant and sustainable materials might become one of the leading alternative technologies especially suitable for large‐scale stationary storage. Various (mixed)phosphate framework materials are attracting much interest mainly due to their high structural stability and diversity. In this study, we report on the successful synthesis of mixed phosphate‐pyrophosphate Na7V4(PO4)(P2O7)4, Na4Fe3(PO4)2P2O7, and Na4Mn3(PO4)2P2O7. The electrochemical properties of these materials are comprehensively characterized in different organic and aqueous electrolytes. The findings reveal that Na7V4(PO4)(P2O7)4 and Na4Fe3(PO4)2P2O7 exhibit very good cycling performance and rate capability in organic solvent‐based electrolytes. However, their performance deteriorates significantly even in 'water‐in‐salt' aqueous electrolytes due to the rapid electrochemical degradation. Na4Mn3(PO4)2P2O7 demonstrates limited electrochemical activity in organic electrolytes and virtually no activity in 'water‐in‐salt' electrolytes, likely due to degradation processes resulting in blocking interphasial layers on electrode particles. These results underscore the need for further research to optimize the performance of these materials and identify potential strategies for enhancing their stability and activity in different electrolytes. [ABSTRACT FROM AUTHOR]

Manganese hexacyanoferrate is a promising cathode material for lithium and sodium ion batteries, however, it suffers of capacity fading during the cycling process. To access the structural and functional characteristics at the nanometer scale, fresh and cycled electrodes are extracted and investigated by transmission soft X‐ray microscopy, which allows chemical characterization with spatial resolution from position‐dependent x‐ray spectra at the Mn L‐, Fe L‐ and N K‐edges. Furthermore, soft X‐rays prove to show superior sensitivity toward Fe, compare to hard X‐rays. Inhomogeneities within the samples are identified, increasing in the aged electrodes, more dramatically in the Li‐ion system, which explains the poorer cycle life as Li‐ion cathode material. Local spectra, revealing different oxidation states over the sample with strong correlation between the Fe L‐edge, Mn L‐edge, and N K‐edge, imply a coupling between redox centers and an electron delocalization over the host framework. [ABSTRACT FROM AUTHOR]

Sodium‐metal batteries (SMBs) are considered a potential alternative to high‐energy lithium‐metal batteries (LMBs). However, the high reactivity of metallic sodium towards common liquid organic electrolytes renders such battery technology particularly challenging. Herein, we propose a multi‐block single‐ion conducting polymer electrolyte (SIPE) doped with ethylene carbonate as suitable electrolyte system for SMBs. This novel SIPE provides a very high ionic conductivity (2.6 mS cm−1) and an electrochemical stability window of about 4.1 V at 40 °C, enabling stable sodium stripping and plating and excellent rate capability of Na||Na3V2(PO4)3 cells up to 2 C. Remarkably, such cells provide a capacity retention of about 85 % after 1,000 cycles at 0.2 C thanks to the very high Coulombic efficiency (99.9 %), resulting from an excellent interfacial stability towards sodium metal and the Na3V2(PO4)3 cathode. [ABSTRACT FROM AUTHOR]

Transitioning to solid‐state batteries using polymer electrolytes results in inherently safer devices and can facilitate the use of sodium metal anodes enabling higher energy densities. In this work, solvent‐free ternary polymer electrolytes based on cross‐linked polyethylene oxide (PEO), sodium bis(fluorosulfonyl) imide (NaFSI) or sodium bis(trifluoromethanesulfonyl) imide (NaTFSI) and N‐butyl‐N‐methyl‐pyrrolidinium‐based ionic liquids (ILs, Pyr14FSI or Pyr14TFSI) are developed. Synthesized polymer membranes are thoroughly characterized, verifying their good thermal and electrochemical stability, as well as a low glass transition and crystallinity, thus high segmental mobility of the polymer matrix. The latter results in good ionic conductivities around 1×10−3 S cm−1 at 20 °C. The polymer electrolytes are successfully employed in sodium‐metal battery (SMB) cells operating at room temperature (RT) and using P2‐Na2/3Ni1/3Mn2/3O2 layered oxide as cathode. The electrochemical performance strongly depends on the choice of anion in the conducting sodium salt and plasticizing IL. Furthermore, this solid‐state SMB approach mitigates capacity fading drivers for the P2‐Na2/3Ni1/3Mn2/3O2, resulting in high Coulombic efficiency (99.91 %) and high capacity retention (99 % after 100 cycles) with good specific capacity (140 mAh g−1). [ABSTRACT FROM AUTHOR]

High‐voltage nickel‐rich layered cathodes possess the requisite, such as excellent discharge capacity and high energy density, to realize lithium batteries with higher energy density. However, such materials suffer from structural and interfacial instability at high voltages (>4.3 V). To reinforce the stability of these cathode materials at elevated voltages, lithium borate salts are investigated as electrolyte additives to generate a superior cathode‐electrolyte interphase. Specifically, the use of lithium bis(oxalato)borate (LiBOB) leads to an enhanced cycling stability with a capacity retention of 81.7%. Importantly, almost no voltage hysteresis is detected after 200 cycles at 1C. This outstanding electrochemical performance is attributed to an enhanced structural and interfacial stability, which is attained by suppressing the generation of micro‐cracks and the superficial structural degradation upon cycling. The improved stability stems from the formation of a fortified borate‐containing interphase which protects the highly reactive cathode from parasitic reactions with the electrolyte. Finally, the decomposition process of LiBOB and the possible adsorption routes to the cathode surface are deduced and elucidated. [ABSTRACT FROM AUTHOR]

Lithium metal is a promising anode material for next‐generation high‐energy‐density batteries but suffers from low stripping/plating Coulombic efficiency and dendritic growth particularly at sub‐zero temperatures. Herein, a poorly‐flammable, locally concentrated ionic liquid electrolyte with a wide liquidus range extending well below 0 °C is proposed for low‐temperature lithium metal batteries. Its all‐anion Li+ solvation and phase‐nano‐segregation solution structure are sustained at low temperatures, which, together with a solid electrolyte interphase rich in inorganic compounds, enable dendrite‐free operation of lithium metal anodes at −20 °C and 0.5 mA cm−2, with a Coulombic efficiency of 98.9 %. As a result, lithium metal batteries coupling thin lithium metal anodes (4 mAh cm−2) and high‐loading LiNi0.8Co0.15Al0.05O2 cathodes (10 mg cm−2) retain 70 % of the initial capacity after 100 cycles at −20 °C. These results, as a proof of concept, demonstrate the applicability of locally concentrated ionic liquid electrolytes for low‐temperature lithium metal batteries. [ABSTRACT FROM AUTHOR]

Manganese hexacyanoferrates (MnHCF) are promising positive electrode materials for non‐aqueous batteries, including Na‐ion batteries, due to their large specific capacity (>130 mAh g−1), high discharge potential and sustainability. Typically, the electrochemical reaction of MnHCF associates with phase and structural changes, due to the Jahn‐Teller (JT) distortion of Mn sites upon the charge process. To understand the effect of the MnHCF structure on its electrochemical performance, two MnHCF materials with different vacancies content are investigated herein. The electrochemical results show that the sample with lower vacancy content (4 %) exhibits relatively higher capacity retention of 99.1 % and 92.6 % at 2nd and 10th cycles, respectively, with respect to 97.4 % and 79.3 % in sample with higher vacancy content (11 %). Ex‐situ X‐ray absorption spectroscopy (XAS) and ex situ X‐ray diffraction (XRD) characterization results show that a weaker cooperative JT‐distortion effect and relatively smaller crystal structure modification occurred for the material with lower vacancies, which explains the better electrochemical performance in cycled electrodes. [ABSTRACT FROM AUTHOR]

Aluminum–sulfur batteries employing high‐capacity and low‐cost electrode materials, as well as non‐flammable electrolytes, are promising energy storage devices. However, the fast capacity fading due to the shuttle effect of polysulfides limits their further application. Herein, alkaline chlorides, for example, LiCl, NaCl, and KCl are proposed as electrolyte additives for promoting the cyclability of aluminum–sulfur batteries. Using NaCl as a model additive, it is demonstrated that its addition leads to the formation of a thicker, NaxAlyO2‐containing solid electrolyte interphase on the aluminum metal anode (AMA) reducing the deposition of polysulfides. As a result, a specific discharge capacity of 473 mAh g−1 is delivered in an aluminum–sulfur battery with NaCl‐containing electrolyte after 50 dis‐/charge cycles at 100 mA g−1. In contrast, the additive‐free electrolyte only leads to a specific capacity of 313 mAh g−1 after 50 cycles under the same conditions. A similar result is also observed with LiCl and KCl additives. When a KCl‐containing electrolyte is employed, the capacity increases to 496 mA h g−1 can be achieved after 100 cycles at 50 mA g−1. The proposed additive strategy and the insight into the solid electrolyte interphase are beneficial for the further development of long‐life aluminum–sulfur batteries. [ABSTRACT FROM AUTHOR]

Non‐flammable ionic liquid electrolytes (ILEs) are well‐known candidates for safer and long‐lifespan lithium metal batteries (LMBs). However, the high viscosity and insufficient Li+ transport limit their practical application. Recently, non‐solvating and low‐viscosity co‐solvents diluting ILEs without affecting the local Li+ solvation structure are employed to solve these problems. The diluted electrolytes, i.e., locally concentrated ionic liquid electrolytes (LCILEs), exhibiting lower viscosity, faster Li+ transport, and enhanced compatibility toward lithium metal anodes, are feasible options for the next‐generation high‐energy‐density LMBs. Herein, the progress of the recently developed LCILEs are summarised, including their physicochemical properties, solution structures, and applications in LMBs with a variety of high‐energy cathode materials. Lastly, a perspective on the future research directions of LCILEs to further understanding and achieve improved cell performances is outlined. [ABSTRACT FROM AUTHOR]

Solid‐state batteries (SSBs) with high‐voltage cathode active materials (CAMs) such as LiNi1−x−yCoxMnyO2 (NCM) and poly(ethylene oxide) (PEO) suffer from "noisy voltage" related cell failure. Moreover, reports on their long‐term cycling performance with high‐voltage CAMs are not consistent. In this work, we verified that the penetration of lithium dendrites through the solid polymer electrolyte (SPE) indeed causes such "noisy voltage cell failure". This problem can be overcome by a simple modification of the SPE using higher molecular weight PEO, resulting in an improved cycling stability compared to lower molecular weight PEO. Furthermore, X‐ray photoelectron spectroscopy analysis confirms the formation of oxidative degradation products after cycling with NCM, for what Fourier transform infrared spectroscopy is not suitable as an analytical technique due to its limited surface sensitivity. Overall, our results help to critically evaluate and improve the stability of PEO‐based SSBs. [ABSTRACT FROM AUTHOR]

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Interfacial dynamics within chemical systems such as electron and ion transport processes have relevance in the rational optimization of electrochemical energy storage materials and devices. Evolving the understanding of fundamental electrochemistry at interfaces would also help in the understanding of relevant phenomena in biological, microbial, pharmaceutical, electronic, and photonic systems. In lithium‐ion batteries, the electrochemical instability of the electrolyte and its ensuing reactive decomposition proceeds at the anode surface within the Helmholtz double layer resulting in a buildup of the reductive products, forming the solid electrolyte interphase (SEI). This review summarizes relevant aspects of the SEI including formation, composition, dynamic structure, and reaction mechanisms, focusing primarily on the graphite anode with insights into the lithium metal anode. Furthermore, the influence of the electrolyte and electrode materials on SEI structure and properties is discussed. An update is also presented on state‐of‐the‐art approaches to quantitatively characterize the structure and changing properties of the SEI. Lastly, a framework evaluating the standing problems and future research directions including feasible computational, machine learning, and experimental approaches are outlined. [ABSTRACT FROM AUTHOR]

Sodium‐ion batteries (SIBs) are postulated as sustainable energy storage devices for light electromobility and stationary applications. The anode of choice in SIBs is hard carbon (HC) due to its electrochemical performance. Among different HC precursors, bio‐waste resources have attracted significant attention due to their low‐cost, abundance, and sustainability. Many bio‐waste materials have been used as HC precursors, but they often require strong acids/bases for pre‐/post‐treatment for HC development. Here, the morphology, microstructure, and electrochemical performance of HCs synthesized from hazelnut shells subjected to different pre‐treatments (i. e., no pre‐treatment, acid treatment, and water washing) were compared. The impact on the electrochemical performance of sodium‐ion cells and the cost‐effectiveness were also investigated. The results revealed that hazelnut shell‐derived HCs produced via simple water washing outperformed those obtained via other processing methods in terms of electrochemical performance and cost–ecological effectiveness of a sodium‐ion battery pack. [ABSTRACT FROM AUTHOR]

The two‐step synthesis of sodium (2,3,5,6‐tetrafluorophenoxy) diethane sulfonate (Na‐TFP) is reported, starting from 2,3,5,6‐tetrafluorohydroquinone as the precursor. Compared with conventional aqueous electrolytes such as 0.5 m NaClO4 and Na2SO4, the 0.5 m aqueous solution of Na‐TFP provides higher ionic conductivity over a wide range of temperature (e.g., >60 mS cm−1 at 20 °C and >70 mS cm−1 at 30 °C) and a wider electrochemical stability window. Electrochemical cells with Na2VTi(PO4)3 as the positive electrode active material and a carbon‐based negative electrode provide a stable capacity for more than 450 cycles in 0.5 m Na‐TFP. Additionally, symmetric cells with Na2VTi(PO4)3 as the active material for the negative and positive electrode are studied. The cells employing 0.5 m Na‐TFP exhibit a good cycling stability at a high dis‐/charge rate of 5C for more than 50 cycles, which is superior to the performance of the cells employing 0.5 m aqueous solutions of NaClO4 and Na2SO4 as the electrolyte. The design of this bifunctional salt may trigger new ideas for the development of water‐based sodium‐ion battery electrolytes. [ABSTRACT FROM AUTHOR]

Copper sulfide has attracted increasing attention as conversion‐type cathode material for, especially, solid‐state lithium‐based batteries. However, the reaction mechanism behind its extraordinary electroactivity is not well understood, and the various explanations given by the scientific community are diverging. Herein, the CuS reaction dynamics are highlighted by examining the occurring redox processes via a cutting‐edge methodology combining X‐ray absorption fine structure spectroscopy, and chemometrics to overcome X‐ray diffraction limitations posed by the poor material's crystallinity. The mathematical approach rules out the formation of intermediates and clarifies the direct conversion of CuS to Cu in a two‐electron process during discharge and reversible oxidation upon delithiation. Two distinct voltage regions are identified corresponding to Cu‐ as well as the S‐redox mechanisms occurring in the material. [ABSTRACT FROM AUTHOR]

"Anode‐less" sodium metal batteries (SMBs) with high energy may become the next‐generation batteries due to the abundant resources. However, their cycling performance is still insufficient for practical uses. Herein, a metal organic frameworks (MOF)‐derived copper‐carbon (Cu@C) composite is developed as a sodiophilic layer to improve the Coulombic efficiency (CE) and cycle life. The Cu particles can provide abundant nucleation sites to spatially guide Na deposition and the carbon framework offer void volume to avoid volume changes during the plating/stripping process. As a result, Cu@C‐coated copper and aluminum foils (denoted as Cu‐Cu@C and Al‐Cu@C foil) can be used as efficient current collectors for sodium plating/stripping, achieving, nearly 1600 and 240 h operation upon cycling at 0.5 mA cm−2 and 1 mA h cm−2, respectively. In situ dilatometry measurements demonstrate that Cu@C promotes the formation of dense Na deposits, thereby inhibiting side reactions, dendrite growth, and accumulation of dead Na. Such current collectors are employed in Na metal cells using carbon‐coated Na3V2(PO4)3 (NVP/C) and copper selenides (Cu2‐xSe@C) cathodes, achieving outstanding rate capability and improved cycling performance. Most noticeably, "anode‐less" Na batteries using Al‐Cu@C as anode and NVP/C as cathode demonstrate promising CE as high as 99.5%, and long‐term cycling life. [ABSTRACT FROM AUTHOR]

The poorly flammable room‐temperature ionic liquid‐based electrolyte composed of lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) and N‐butyl‐N‐methylpyrrolidinium bis(fluorosulfonyl)imide (Pyr14FSI) with fluoroethylene carbonate (FEC) as an additive is investigated towards its compatibility with the LiNi0.88Co0.09Mn0.03O2 (NCM88) cathode and a high‐capacity Si/graphite (SiG) anode, revealing a remarkably stable performance in lithium‐ion cells. Interestingly, this dual‐anion electrolyte with FEC additive forms a stable electrode‐electrolyte interphase on both sides, which suppresses the morphological degradation of the electrode materials and continuous electrolyte decomposition. Consequently, lithium‐ion cells using such dual‐anion ionic liquid‐based electrolyte display significantly improved cycling stability compared to conventional carbonate ester‐based electrolyte, achieving a high specific energy of 385 Wh kg−1 (based on both cathode and anode active materials weight) with a capacity retention of 74 % after 200 cycles at 0.2 C, demonstrating the possibility to realize safe and high energy density LIBs. [ABSTRACT FROM AUTHOR]

Aluminum is a promising material as an alternative green energy carrier thanks to its very high volumetric energy density and full recyclability. Aluminum oxidation with steam in the temperature range of 600–900 °C is investigated as an innovative and promising methodology for aluminum conversion resulting in hydrogen and heat production. Reaction times, hydrogen production rate and yield are assessed varying operational parameters such as temperature, steam to aluminum ratio, and gas hourly space velocity within the reactor. The conversion yield of aluminum is assessed at 73.13% at 900 °C and ambient pressure, with reaction times comparable with the one reported in the literature for water oxidation in batch‐pressurized reactors. Moreover, over 750 °C, alumina is produced in microparticles, allowing reactor operating times up to 1 h without incurring in the clogging effect. The obtained results are promising for the continuous operating condition of a future full‐scale reactor. [ABSTRACT FROM AUTHOR]

The realization of a fully decarbonized mobility and energy system requires the availability of carbon‐free electricity and fuels which can be ensured only by cost‐efficient and sustainable energy storage technologies. In line with this demand, a techno‐economic evaluation of aluminum as a cross‐sectoral renewable energy carrier is conducted. The assessment, based on a newly developed process, involves the wet combustion of Aluminum at 700 °C resulting in heat and hydrogen (H2) generation. The designed conversion plant enables the contemporaneous generation of electricity and on demand H2 (up to 4 MW and 46.8 kg h–1) with round‐trip efficiencies as high as 40.7% and full recycling of the Al2O3 waste. This study, assuming the carbon‐free production of Al and three different energy cost scenarios, proves the feasibility of the e‐fueling station business case. The overall energy conversion including fuel production (power‐to‐Al), utilization (Al‐to‐power and Al‐to‐H2), and recycling requires a capital investment of 5200 € per kW installed power without additional primary material demand. Hence, the estimated power‐to‐X cost for the Al‐based H2 is estimated in the range of 4.2–9.6 € kg–1 H2, while wind and solar power based green H2 production cost varies from 6.5 to 12.1 € kg–1 H2. [ABSTRACT FROM AUTHOR]

Delocalized electron engineering of layer‐structured V2O5 cathode is proposed to facilitate free Zn2+ formation and diffusion under low temperature. [ABSTRACT FROM AUTHOR]

Lithium metal batteries (LMBs) with nickel‐rich cathodes are promising candidates for next‐generation, high‐energy batteries. However, the highly reactive electrodes usually exhibit poor interfacial compatibility with conventional electrolytes, leading to limited cyclability. Herein, a locally concentrated ionic liquid electrolyte (LCILE) consisting of lithium bis(fluorosulfonyl)imide (LiFSI), 1‐ethyl‐3‐methylimidazolium bis(fluorosulfonyl)imide (EmimFSI), and 1,2‐difluorobenzene (dFBn) is designed to overcome this challenge. As a cosolvent, dFBn not only promotes the Li+ transport with respect to the electrolyte based on the ionic liquid only, but also has beneficial effects on the electrode/electrolyte interphases (EEIs) on lithium metal anodes (LMAs) and LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes. As a result, the developed LCILE enables dendrite‐free cycling of LMAs with a coulombic efficiency (CE) up to 99.57% at 0.5 mA cm−2 and highly stable cycling of Li/NMC811 cells (4.4 V) at C/3 charge and 1 C discharge (1 C = 2 mA cm−2) for 500 cycles with a capacity retention of 93%. In contrast, the dFBn‐free electrolyte achieves lithium stripping/plating CE, and the Li/NMC811 cells' capacity retention of only 98.22% and 16%, respectively under the same conditions. The insight into the coordination structure, promoted Li+ transport, and EEI characteristics gives fundamental information essential for further developing (IL‐based) electrolytes for long‐life, high‐energy LMBs. [ABSTRACT FROM AUTHOR]

Lithium‐sulfur (Li−S) batteries are recognized as one of the most promising technologies with the potential to become the next‐generation batteries. However, to ensure Li−S batteries reach commercialization, complex challenges remain, among which the tailoring of an appropriate electrolyte is the most important. This review discusses the role of electrolytes in Li−S batteries, focusing on the main issues and solutions for the shuttle mechanism of polysulfides and the instability of the interface with lithium metal. Herein, we present a background on Li−S chemistry followed by the state‐of‐the‐art electrolytes highlighting the different strategies undertaken with liquid and solid electrolytes. [ABSTRACT FROM AUTHOR]

Transition metal chalcogenides have been regarded as promising storage materials for sodium ions owing to their high theoretical capacity. Herein, copper‐based metal–organic frameworks (Cu‐BTC) are reported as precursors to fabrica copper chalcogenides‐carbon composites, namely Cu1.8S@C and Cu2‐xSe@C. The materials exhibit excellent electrochemical performance with high specific capacities (504 mAh g–1 for Cu1.8S@C and 317 mAh g–1 for Cu2‐xSe@C at 0.1 A g–1) and long‐term cycling stability when used as anode materials in cells employing carbon‐coated Na3V2(PO4)3 (NVP/C) positive electrodes. The Cu2‐xSe@C||NVP/C cell delivers a specific capacity of 73 mAh g–1 at 1.2 A g–1 (based on cathode mass) and excellent cycling stability (capacity retention of 85% after 500 cycles at 0.12 A g–1) with Coulombic efficiency of ≈99.9%. Moreover, the Cu2‐xSe@C composite performs well as positive electrode storage material in a sodium‐metal cell, offering a high reversible capacity of 216 mAh (per gram of Cu2‐xSe@C) after 1800 cycles at 2 A g–1 and enabling high specific energy and power. [ABSTRACT FROM AUTHOR]

Solid‐state batteries (SSBs) are promising candidates to significantly exceed the energy densities of today's state‐of‐the‐art technology, lithium‐ion batteries (LIBs). To enable this advancement, optimizing the solid electrolyte (SE) is the key. β‐Li3PS4 (β‐LPS) is the most studied member of the Li2S‐P2S5 family, offering promising properties for implementation in electric vehicles. In this work, the microstructure of this SE and how it influences the electrochemical performance are systematically investigated. To figure this out, four batches of β‐LPS electrolyte with different particle size, shape, and porosity are investigated in detail. It is found that differences in pellet porosities mostly originate from single‐particle intrinsic features and less from interparticle voids. Surprisingly, the β‐LPS electrolyte pellets with the highest porosity and larger particle size not only show the highest ionic conductivity (up to 0.049 mS cm–1 at RT), but also the most stable cycling performance in symmetrical Li cells. This behavior is traced back to the grain boundary resistance. Larger SE particles seem to be more attractive, as their grain boundary contribution is lower than that of denser pellets prepared using smaller β‐LPS particles. [ABSTRACT FROM AUTHOR]

Polymer electrolytes are considered potential key enablers for lithium‐metal batteries due to their compatibility with the lithium‐metal negative electrode. Herein, cross‐linked self‐standing single‐ion conducting polymer electrolytes are obtained via a facile UV‐initiated radical polymerization using pentaerythritol tetraacrylate as the cross‐linker and lithium (3‐methacryloyloxypropylsulfonyl)‐(trifluoromethylsulfonyl)imide as the ionic functional group. Incorporating propylene carbonate as charge‐transport supporting additive allowed for achieving single‐ion conductivities of 0.21 mS cm−1 at 20 °C and 0.40 mS cm−1 at 40 °C, while maintaining a suitable electrochemical stability window for 4 V‐class positive electrodes (cathodes). As a result, this single‐ion polymer electrolyte featured good cycling stability and rate capability in Li||LiFePO4 and Li||LiNi0.6Mn0.2Co0.2O2 cells. These results render this polymer electrolyte as potential alternative to liquid electrolytes for high‐energy lithium‐metal batteries. [ABSTRACT FROM AUTHOR]

The full commercialization of sodium‐ion batteries (SIBs) is still hindered by their lower electrochemical performance and higher cost ($ W−1 h−1) with respect to lithium‐ion batteries. Understanding the electrode–electrolyte interphase formation in both electrodes (anode and cathode) is crucial to increase the cell performance and, ultimately, reduce the cost. Herein, a step forward regarding the study of the cathode–electrolyte interphase (CEI) by means of X‐ray photoelectron spectroscopy (XPS) has been carried out by correlating the formation of the CEI on the P2‐Na0.67Mn0.8Ti0.2O2 layered oxide cathode with the cycling rate. The results reveal that the applied current density affects the concentration of the formed interphase species, as well as the thickness of CEI, but not its chemistry, indicating that the electrode–electrolyte interfacial reactivity is mainly driven by thermodynamic factors. [ABSTRACT FROM AUTHOR]

To tackle the poor chemical/electrochemical stability of Li1+xAlxTi2‐x(PO4)3 (LATP) against Li and poor electrode|electrolyte interfacial contact, a thin poly[2,3‐bis(2,2,6,6‐tetramethylpiperidine‐N‐oxycarbonyl)norbornene] (PTNB) protection layer is applied with a small amount of ionic liquid electrolyte (ILE). This enables study of the impact of ILEs with modulated composition, such as 0.3 lithium bis(fluoromethanesulfonyl)imide (LiFSI)‐0.7 N‐butyl‐N‐methylpyrrolidinium bis(fluoromethanesulfonyl)imide (Pyr14FSI) and 0.3 LiFSI‐0.35 Pyr14FSI‐0.35 N‐butyl‐N‐methylpyrrolidinium bis(trifluoromethanesulfonyl)imide (Pyr14TFSI), on the interfacial stability of PTNB@Li||PTNB@Li and PTNB@Li||LiNi0.8Co0.1Mn0.1O2 cells. The addition of Pyr14TFSI leads to better thermal and electrochemical stability. Furthermore, Pyr14TFSI facilitates the formation of a more stable Li|hybrid electrolyte interface, as verified by the absence of lithium "pitting corrosion islands" and fibrous dendrites, leading to a substantially extended lithium stripping‐plating cycling lifetime (>900 h). Even after 500 cycles (0.5C), PTNB@Li||LiNi0.8Co0.1Mn0.1O2 cells achieve an impressive capacity retention of 89.1 % and an average Coulombic efficiency of 98.6 %. These findings reveal a feasible strategy to enhance the interfacial stability between Li and LATP by selectively mixing different ionic liquids. [ABSTRACT FROM AUTHOR]

Single‐ion conducting polymer electrolytes are considered particularly attractive for realizing high‐performance solid‐state lithium‐metal batteries. Herein, a polysiloxane‐based single‐ion conductor (PSiO) is investigated. The synthesis is performed via a simple thiol‐ene reaction, yielding flexible and self‐standing polymer electrolyte membranes (PSiOM) when blended with poly(vinylidene fluoride‐co‐hexafluoropropylene) (PVdF‐HFP). When incorporating 57 wt% of organic carbonates, these polymer membranes provide a Li+ conductivity of >0.4 mS cm−1 at 20 °C and a wide electrochemical stability window of more than 4.8 V. This excellent electrochemical stability allows for the highly reversible cycling of symmetric Li||Li cells as well as high‐energy Li||LiNi0.6Mn0.2Co0.2O2 (NMC622) and Li||LiNi0.8Mn0.1Co0.1O2 (NMC811) cells for several hundred cycles at relatively high discharge and charge rates. Remarkably, Li||NMC811 cells with high mass loading cathodes provide more than 76% capacity retention at a high current density of 1.44 mA cm−2, thus rendering this polymer electrolyte suitable for high‐performance battery applications. [ABSTRACT FROM AUTHOR]

Aqueous ammonium‐ion (NH4+) batteries (AAIB) are a recently emerging technology that utilize the abundant electrode resources and the fast diffusion kinetics of NH4+ to deliver an excellent rate performance at a low cost. Although significant progress has been made on AAIBs, the technology is still limited by various challenges. In this Minireview, the most recent advances are comprehensively summarized and discussed, including cathode and anode materials as well as the electrolytes. Finally, a perspective on possible solutions for the current limitations of AAIBs is provided. [ABSTRACT FROM AUTHOR]

Rechargeable Li‐ion battery technology has progressed due to the development of a suitable combination of electroactive materials, binders, electrolytes, additives, and electrochemical cycling protocols that resulted in the formation of a stable electrode‐electrolyte interphase. It is expected that Na‐ion technology will attain a position comparable to Li‐ion batteries dependent on advancements in establishing a stable electrode‐electrolyte interphase. However, Li and Na are both alkali metals with similar characteristics, yet the physicochemical properties of these systems differ. For this reason, a detailed study on the electrode‐electrolyte interphase properties, composition, and structure is required to understand the factors that influence the battery's behavior. Herein, the research that has been performed on the electrode‐electrolyte interphase for both anode and cathode in the most important families of electrode materials, including carbonate ester‐based and advanced electrolytes such as ether‐based carbonates and ionic liquids is presented. [ABSTRACT FROM AUTHOR]

Spinel cobaltites are widely presented as promising pseudocapacitive materials, however, a fundamental understanding of their structure–property relationship at an atomic level remains vague. Herein, their geometrical‐site‐dependent charge storage capability is investigated by substituting Co with inactive Zn and redox‐active Mn. Experimental and theoretical analyses reveal that redox‐active cations in octahedral sites contribute to enhanced capacitance, intrinsically determined by the covalency competition between tetrahedral and octahedral sites. The Zn2+ incorporation leads to increased occupancy of Co in octahedral sites and 2.9× increased capacitance at 1 A g−1 current density, whereas the substituted Mn cations mainly sit in octahedral sites which can react with OH− upon cycling and separate on the spinel surface to reconstruct into δ‐MnO2 nanosheets, leading to 4× increased capacitance at 1 A g−1 current density with a detected K+ ion intercalation. Thus, the exposure of redox‐active cations in octahedral sites and their intrinsic properties are influential in determining spinel oxides' pseudocapacitive properties. This work provides a general principle to optimize the pseudocapacitive properties of spinel cobaltites by deliberately selecting cations for substitution and controlling their distribution in octahedral/tetrahedral sites. It also offers a fundamental understanding of geometrical‐site‐dependent activity, and can effectively guide the development of spinel oxides for enhanced pseudocapacitance. [ABSTRACT FROM AUTHOR]