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Elevating the charging cut-off voltage is one of the efficient approaches to boost the energy density of Li-ion batteries (LIBs). However, this method is limited by the occurrence of severe parasitic reactions at the electrolyte/electrode interfaces. Herein, to address this issue, we design a non-flammable fluorinated sulfonate electrolyte by multifunctional solvent molecule design, which enables the formation of an inorganic-rich cathode electrolyte interphase (CEI) on high-voltage cathodes and a hybrid organic/inorganic solid electrolyte interphase (SEI) on the graphite anode. The electrolyte, consisting of 1.9 M LiFSI in a 1:2 v/v mixture of 2,2,2-trifluoroethyl trifluoromethanesulfonate and 2,2,2-trifluoroethyl methanesulfonate, endows 4.55 V-charged graphite||LiCoO2 and 4.6 V-charged graphite||NCM811 batteries with capacity retentions of 89% over 5329 cycles and 85% over 2002 cycles, respectively, thus resulting in energy density increases of 33% and 16% compared to those charged to 4.3 V. This work demonstrates a practical strategy for upgrading the commercial LIBs. The parasitic reactions at the electrolyte/electrode interfaces inhibit the increase of the charging cut-off voltage and the improvement of energy density. Herein, the authors design multifunctional solvent molecules and propose a practical design principle to stabilize the electrolyte/electrode interfaces for high-voltage Li ion batteries. [ABSTRACT FROM AUTHOR]

All‐solid‐state lithium batteries (ASSLBs) are considered as an alternative solution to lithium‐ion batteries, because of their safety and high theoretical energy density. Argyrodite‐based solid‐electrolytes (SEs), Li6PS5X (X = Cl, Cl0.5Br0.5 or Br), are promising candidates for ASSLBs. Most of the previous reports have used Li6PS5Cl as the default SE composition. Here, the electrochemical behavior of three different argyrodites with Cl− or Br−, or both, as the halogen is systematically studied. Using LiNi0.6Co0.2Mn0.2O2 as a model cathode, the behavior of these SEs in ASSLB cells is also studied. SEs containing Br show higher near‐room‐temperature ionic conductivity (>2 mS cm−1) and the critical current density (≥1 mA cm−2) during Li plating/stripping, and are stable up to 5 V versus Li/Li+. Li6PS5Br gives the best electrochemical performance in terms of C‐rate and long‐term cycling among the three samples. Specifically, the cathode delivers an initial reversible capacity of 156 mAh g−1, with ≈27% irreversible capacity loss and 90% capacity retention over 100 cycles, and >99% Coulombic efficiency. It delivers ≈56 mAh g−1 at 10C, 36% of its initial capacity at 0.2C, whereas Li6PS5Cl and Li6PS5Cl0.5Br0.5 deliver only 20 and 46 mAh g−1 at 10C. [ABSTRACT FROM AUTHOR]

Rechargeable magnesium batteries (RMBs) are highly attractive due to their high volumetric capacity, relatively low cost, and enhanced safety. Significant progress in the development of RMBs was the introduction of nonaqueous electrolyte solutions that enable reversible electrodeposition of Mg metal. These solutions contain a unique mixture of organo-aluminum and chloro -aluminum species. While these solutions are shown to be stable during cathodic polarization, the presence of chlorine anions in the solution can promote the corrosion process during the anodic polarization. Among all the cell components, the cathode current collector is most prone to corrosive processes. In this study, we characterize the corrosion behavior of different metallic current collectors in standard APC (All-Phenyl Complex) electrolyte solutions by following their electrochemical response and surface morphology changes during anodic polarization. In addition, we investigate the influence of carbon coating on the corrosive behavior of Ni metal. The study shows the efficacy of carbon coating on the current collector. We demonstrate that Ni@C current collector possesses higher corrosion pit initiation potential (2.25 V vs Mg/Mg2+) with respect to the uncoated metallic foils. Improving the anodic stability of the current collectors is a crucial step in the development of a practical rechargeable Mg battery. [ABSTRACT FROM AUTHOR]

Herein, three electrolyte families (liquid, polymer, and ceramic) are compared and their future perspectives in research and application are discussed. First, the transport mechanism for each family is presented, as their beneficial and taxing properties stem from the differences in these mechanisms. Following a discussion of each group, their advantages, and limitations, a clear conclusion can be drawn on the need to focus on research on solid electrolytes, which present brighter prospects in terms of significant future advances in lithium‐based battery systems. Yet, in a more realistic perspective based on current work by companies such as Samsung, Solid Power, and QuantumScape, it is our understanding that the hybridization of polymer and solid electrolytes will likely dominate practical electrolyte chemistries, at least in the near future, given that the synergetic properties of the two families are larger than their single parts. Inevitably, solid‐state electrolytes will dominate, mainly in electric vehicles and future lithium battery chemistries. [ABSTRACT FROM AUTHOR]

Aluminum metal is a promising anode material for next generation rechargeable batteries owing to its abundance, potentially dendrite-free deposition, and high capacity. The rechargeable aluminum/sulfur (Al/S) battery is of great interest owing to its high energy density (1340 Wh kg−1) and low cost. However, Al/S chemistry suffers poor reversibility owing to the difficulty of oxidizing AlS x. Herein, we demonstrate the first reversible Al/S battery in ionic-liquid electrolyte with an activated carbon cloth/sulfur composite cathode. Electrochemical, spectroscopic, and microscopic results suggest that sulfur undergoes a solid-state conversion reaction in the electrolyte. Kinetics analysis identifies that the slow solid-state sulfur conversion reaction causes large voltage hysteresis and limits the energy efficiency of the system. [ABSTRACT FROM AUTHOR]

The quest for renewable energy storage solutions highlights the need for systems prioritizing safety, cost-effectiveness, and accessibility of materials and compartments. Unlike traditional flow systems requiring frequent upkeep and extensive space, the static setup of rechargeable zinc-bromide batteries (RZBBs) in an aqueous environment emerges as a promising option due to its component abundance, secure setup, and compact storage volume. This study focuses on the interplay between zinc-bromide complexes and the pores of the carbon cathodes' scaffold. We uncover noteworthy insights by meticulously controlling the porous structure of the carbon scaffold and the ZnBr 2 concentration in the electrolyte while upholding a high Coulombic efficiency (≥96 %). In materials with small pore volumes, even relatively low concentrations and the highest conductivity (3M) lead to space occupation by the complexes impacting the achieved capacity. This is particularly evident at high concentrations (10M) exhibiting low capacities. Conversely, macro-porous carbon-based cathodes (like CNTs) exhibit a reversal of this trend, showcasing advantages at high electrolyte concentrations. These findings indicate a unique behavior of zinc-bromide aqueous electrolytes in porous carbonaceous media, emphasizing the pivotal role of considering the interplay between cathodes' surfaces and electrolyte concentration for optimal performance. • Sheds light on the electrode-electrolyte interface of ZBB in a static configuration. • Unique behavior of zinc-bromide aqueous electrolytes in porous carbonaceous media. • The linkage of multiple zinc-ion complexes in [Zn y -Br x ]2y-x. • The unique systems discussed here belong to the anion⋯anion dimers category. [ABSTRACT FROM AUTHOR]

(CF3SO2)2NLi is added to the non-nucleophilic ((Tms)2N)2Mg electrolyte used in a Mg/S secondary battery system with an activated carbon/sulfur cathode and Mg foil as anode separated by a Whatman glass fiber separator. [ABSTRACT FROM AUTHOR]

The goal of limiting global warming to 1.5 °C requires a drastic reduction in CO2 emissions across many sectors of the world economy. Batteries are vital to this endeavor, whether used in electric vehicles, to store renewable electricity, or in aviation. Present lithium-ion technologies are preparing the public for this inevitable change, but their maximum theoretical specific capacity presents a limitation. Their high cost is another concern for commercial viability. Metal-air batteries have the highest theoretical energy density of all possible secondary battery technologies and could yield step changes in energy storage, if their practical difficulties could be overcome. The scope of this review is to provide an objective, comprehensive, and authoritative assessment of the intensive work invested in nonaqueous rechargeable metal-air batteries over the past few years, which identified the key problems and guides directions to solve them. We focus primarily on the challenges and outlook for Li-O2 cells but include Na-O2, K-O2, and Mg-O2 cells for comparison. Our review highlights the interdisciplinary nature of this field that involves a combination of materials chemistry, electrochemistry, computation, microscopy, spectroscopy, and surface science. The mechanisms of O2 reduction and evolution are considered in the light of recent findings, along with developments in positive and negative electrodes, electrolytes, electrocatalysis on surfaces and in solution, and the degradative effect of singlet oxygen, which is typically formed in Li-O2 cells. [ABSTRACT FROM AUTHOR]

• First ever synthesis and isolation of MgCl+ cations containing Mg electrolytes. • Novel MgCl(THF) 5 PhAlCl 3 /THF electrolyte show reversible Mg deposition/dissolution. • Electrochemical "conditioning" increases the cycling efficiency to around 95%. • Investigation of electrolyte solution with Mg prototype full cell configuration. Synthesis of complex magnesium cations in ethereal solutions, is receiving a lot of attention due to their potential utilization in rechargeable magnesium batteries (RMB). The simplest complex cation, namely, solvated MgCl+, was hypothesized and reported as the most important cation in nonaqueous magnesium electrolyte solutions chemistry. However, such ions have never been isolated as the only cationic species in ethereal solutions developed for RMB. In this study, we report on successful isolation of the pure electrolyte MgCl(THF) 5 +- PhAlCl 3 , and on the electrochemical behavior of it in ethereal solutions. The structure of this compound was proved by single-crystal X-ray diffraction, Raman, and NMR spectroscopies. The novel MgCl(THF) 5 PhAlCl 3 /THF electrolyte solutions exhibit reversible Mg deposition/dissolution processes with anodic stability up to 2.7 V. The application of electrochemical cleaning pre-treatment for these solutions enabled to profoundly increase the coulombic efficiency of their Mg deposition/dissolution processes. Examining Mg prototype batteries with Mg foil anodes, composite Mo 6 S 8 Chevrel phase (CP) cathodes containing these solutions exhibited a viable battery performance, indicating that upon a further optimization, electrolyte solutions based on the complex MgCl(THF) 5 +- PhAlCl 3 −electrolyte may be suitable for practical RMB. [Display omitted] [ABSTRACT FROM AUTHOR]

• Ten carbon materials are tested in Zn-air batteries with non-alkaline electrolytes. • At 0.1 mA cm−2, energy efficiency logarithmically depends on the BET surface area. • At 0.1 mA cm−2, more hydrophilic cathodes have lower initial overpotentials. • At 1 mA cm−2, materials with micron-sized particles have poor ORR performance. Rechargeable Zn-air batteries (RZABs) with non-alkaline electrolytes are a promising type of energy storage devices that potentially combine low cost, high energy density and safety. However, cathode materials for these devices remain poorly developed. We present a systematic study of how structure of carbons affects their performance as cathode scaffolds in non-alkaline RZABs. Ten commercially available types of carbon are characterized and tested in Zn-air battery cathodes with 1 M Zn(OAc) 2 or ZnSO 4 solutions in H 2 O as electrolytes. At a low current density (0.1 mA cm−2), there is a roughly linear dependence between the roundtrip energy efficiency and the logarithm of BET surface area, and this dependence is relevant across materials with different morphology and graphitization degree. Lower overpotentials at the initial cycles are observed for cathodes that are more hydrophilic. At higher currents (1 mA cm−2), morphology plays an important role for oxygen reduction kinetics, with nanosized carbons having a much better performance compared to microporous materials with micron-sized particles. Overall, the best performance in non-alkaline RZABs is achieved for nanosized carbons with high specific surface area (>450 m2 g − 1). Our findings help to formulate structural and morphological guidelines for choosing or synthesizing an optimal carbon scaffold for RZABs. [Display omitted] [ABSTRACT FROM AUTHOR]