Desolvation Penalty Research Articles

Improving the rate and cycle performance of V-based cathodes through regulation of the Zn2+ desolvation process

The large-scale application of vanadium in AZIBs has been hampered by its inferior rate performance and cycling stability, arising from the desolvation penalty of Zn2+ and the dissolution of vanadium. To address this issue, hydroxymethyl zinc phosphates Zn(O3PCH2OH) (ZnOPC) have been innovatively employed as a cathode electrolyte interphase (CEI) material to enhance the electrochemical performance of V2O5·nH2O (VO) cathode. The organized path structure of ZnOPC, coupled with its numerous hydroxyl groups, significantly reduces the desolvation penalty of Zn[H2O]62+ by forming new hydrogen bonds with the solvent-shell water molecules. More importantly, ZnOPC effectively mitigates vanadium dissolution by immobilizing free H2O which comes from the desolvation of Zn[H2O]62+. Consequently, the modified VO cathode exhibits superior rate performance and extraordinary cycling life, maintaining a specific capacity of 202.7 mAh/g after 7000 cycles at 10 A/g and 238.1 mAh/g at the high current of 20 A/g. These results offer a new prospect for designing high electrochemical performance vanadium-based cathode for AZIBs.

Interaction of anti-inflammatory drug naproxen with essential amino acids: Quantitative thermodynamic insights

A combination of ultrasensitive isothermal titration calorimetry and uv–visible spectroscopy has been employed to unravel interaction of anti-inflammatory drug naproxen with five essential amino acids L-arginine, L-lysine, L-phenylalanine, L-valine and L-tryptophan. The nature of interaction in each case has been examined based on standard molar enthalpy of interaction ΔHmo and changes in the spectral properties. The values and sign of ΔHmo have been related with the nature of interacting groups and solvent reorganization as a result of drug-amino acid association. Exothermic standard molar enthalpy of interaction of naproxen with L-arginine indicated significant of polar interactions, and endothermic heat effects with all other amino acids suggested dominance of hydrophobic effect and desolvation penalty in the association process. The overall value of enthalpy of interaction for all the studied amino acids is less than 2 kJmol-1 suggesting that these interactions are not very strong. The uv–visible results provided support to ITC results in obtaining mechanistic insights into the nature of interactions. The results derive significance from the fact that sometimes anti-inflammatory drug naproxen may be administrated along with supplements of essential amino acids. In case there is a strong drug-amino acids interaction, efficacy of each one may be affected.

Toward a quantitative interfacial description of solvation for Li metal battery operation under extreme conditions

The future application of Li metal batteries (LMBs) at scale demands electrolytes that endow improved performance under fast-charging and low-temperature operating conditions. Recent works indicate that desolvation kinetics of Li+ plays a crucial role in enabling such behavior. However, the modulation of this process has typically been achieved through inducing qualitative degrees of ion pairing into the system. In this work, we find that a more quantitative control of the ion pairing is crucial to minimizing the desolvation penalty at the electrified interface and thus the reversibility of the Li metal anode under kinetic strain. This effect is demonstrated in localized electrolytes based on strongly and weakly bound ether solvents that allow for the deconvolution of solvation chemistry and structure. Unexpectedly, we find that maximum degrees of ion pairing are suboptimal for ultralow temperature and high-rate operation and that reversibility is substantially improved via slight local dilution away from the saturation point. Further, we find that at the optimum degree of ion pairing for each system, weakly bound solvents still produce superior behavior. The impact of these structure and chemistry effects on charge transfer are then explicitly resolved via experimental and computational analyses. Lastly, we demonstrate that the locally optimized diethyl ether-based localized-high-concentration electrolytes supports kinetic strained operating conditions, including cycling down to -60 °C and 20-min fast charging in LMB full cells. This work demonstrates that explicit, quantitative optimization of the Li+ solvation state is necessary for developing LMB electrolytes capable of low-temperature and high-rate operation.

An amide to thioamide substitution improves the permeability and bioavailability of macrocyclic peptides

Solvent shielding of the amide hydrogen bond donor (NH groups) through chemical modification or conformational control has been successfully utilized to impart membrane permeability to macrocyclic peptides. We demonstrate that passive membrane permeability can also be conferred by masking the amide hydrogen bond acceptor (>C = O) through a thioamide substitution (>C = S). The membrane permeability is a consequence of the lower desolvation penalty of the macrocycle resulting from a concerted effect of conformational restriction, local desolvation of the thioamide bond, and solvent shielding of the amide NH groups. The enhanced permeability and metabolic stability on thioamidation improve the bioavailability of a macrocyclic peptide composed of hydrophobic amino acids when administered through the oral route in rats. Thioamidation of a bioactive macrocyclic peptide composed of polar amino acids results in analogs with longer duration of action in rats when delivered subcutaneously. These results highlight the potential of O to S substitution as a stable backbone modification in improving the pharmacological properties of peptide macrocycles.

Surface‐Redox Pseudocapacitance‐Dominated Charge Storage Mechanism Enabled by the Reconstructed Cathode/Electrolyte Interface for High‐Rate Magnesium Batteries

AbstractTh all phenyl complex (APC) electrolyte is generally accepted to be compatible with Mg metal anodes, offering excellent plating/stripping reversibility. However, the large Cl desolvation penalty of the MgCl+ solvation structure in APC electrolyte causes a high reaction energy barrier at the cathode/electrolyte interface, resulting in unsatisfactory rate performance. Herein, the interface reconstruction strategy of an anatase TiO2 cathode is proposed by the combination of ultrathin carbon coating and oxygen vacancies, which realizes the fast surface‐redox pseudocapacitance charge storage mechanism via MgCl+, circumventing the sluggish solid‐phase migration of Mg2+. Theoretical calculations verify that the introduction of oxygen vacancies in TiO2, not only increases the intrinsic electronic conductivity, but also improves the adsorption capability for MgCl+, which enhances the surface‐redox pseudocapacitance of TiO2. Moreover, in situ Raman measurements, ex situ XPS spectra and XRD patterns demonstrate the structural integrity of TiO2 without undergoing phase change and the rapid reversible storage of MgCl+. Furthermore, in situ electrochemical impedance spectra reveal that the reconstructed cathode/electrolyte interface promotes the kinetics of active cations and induces the less potential‐dependent charge storage process. Consequently, TiO2 exhibits a remarkable rate performance (discharge capacity of 68.9 mAh g−1 at 1 A g−1) and long‐lifespan over 3000 cycles at 0.5 A g−1.

Role of water structural properties in interaction of amino acids with metal ions of varying size and electrons in d-block or main group elements: Quantitative thermodynamic analysis

Interactions of a homologous series of amino acids (glycine, l-alanine, DL-α-amino-n-butyric acid, l-valine and l-leucine) with salts (LiCl, NaCl, KCl, CaCl2, MnCl2, CoCl2) having common anion, but cation having varying d-electronic configuration and alkaline earth metals have been studied in aqueous solutions employing ultrasensitive isothermal titration calorimetry. Standard molar enthalpies of amino acid-salt interactions have been interpreted in terms of predominant ionic association between charged centres and the corresponding desolvation penalty. Extra crystal field stabilization experienced by Mn2+(aq) and Ca2+(aq) due to d5 and d10 electronic configuration has been addressed based on results of standard molar enthalpies of interaction. The results indicate significant desolvation cost predominantly from hydration of the cations of the salts rather than from hydration of zwitter-ionic ends of the amino acids irrespective of their chain length. This is also indicated by stronger endothermic interaction of the amino acids with the bivalent cations than that with the monovalent ones. The results obtained in this work provide essential mechanistic insights into nature of amino acid interactions modulated by variation in cationic d-electronic configuration in terms of enthalpies of interaction.

Loading dynamics of one SARS-CoV-2-derived peptide into MHC-II revealed by kinetic models

Major histocompatibility complex class II (MHC-II) plays an indispensable role in activating CD4+ T cell immune responses by presenting antigenic peptides on the cell surface for recognition by T cell receptors. The assembly of MHC-II and antigenic peptide is therefore a prerequisite for the antigen presentation. To date, however, the atomic-level mechanism underlying the peptide-loading dynamics for MHC-II is still elusive. Here, by constructing Markov state models based on extensive all-atom molecular dynamics simulations, we reveal the complete peptide-loading dynamics into MHC-II for one SARS-CoV-2 S-protein-derived antigenic peptide (235ITRFQTLLALHRSYL249). Our Markov state model identifies six metastable states (S1–S6) during the peptide-loading process and determines two dominant loading pathways. The peptide could potentially approach the antigen-binding groove via either its N- or C-terminus. Then, the consecutive insertion of several anchor residues into the binding pockets profoundly dictates the peptide-loading dynamics. Notably, the MHC-II αA52-E55 motif could guide the peptide loading into the antigen-binding groove via forming β-sheets conformation with the incoming peptide. The rate-limiting step, namely S5→S6, is mainly attributed to a considerable desolvation penalty triggered by the binding of the peptide C-terminus. Moreover, we further examined the conformational changes associated with the peptide exchange process catalyzed by the chaperon protein HLA-DM. A flipped-out conformation of MHC-II αW43 captured in S1–S3 is considered a critical anchor point for HLA-DM to modulate the structural dynamics. Our work provides deep structural insights into the key regulatory factors in MHC-II responsible for peptide recognition and guides future design for peptide vaccines against SARS-CoV-2.

Heterogeneous and Allosteric Role of Surface Hydration for Protein-Ligand Binding.

Atomistic-level understanding of surface hydration mediating protein-protein interactions and ligand binding has been a challenge due to the dynamic nature of water molecules near the surface. We develop a computational method to evaluate the solvation free energy based on the density map of the first hydration shell constructed from all-atom molecular dynamics simulation and use it to examine the binding of two intrinsically disordered ligands to their target protein domain. One ligand is from the human protein, and the other is from the 1918 Spanish flu virus. We find that the viral ligand incurs a 6.9 kcal/mol lower desolvation penalty upon binding to the target, which is consistent with its stronger binding affinity. The difference arises from the spatially fragmented and nonuniform water density profiles of the first hydration shell. In particular, residues that are distal from the ligand-binding site contribute to a varying extent to the desolvation penalty, among which the "entropy hotspot" residues contribute significantly. Thus, ligand binding alters hydration on remote sites in addition to affecting the binding interface. The nonlocal effect disappears when the conformational motion of the protein is suppressed. The present results elucidate the interplay between protein conformational dynamics and surface hydration. Our approach of measuring the solvation free energy based on the water density of the first hydration shell is tolerant of the conformational fluctuation of protein, and we expect it to be applicable to investigating a broad range of biomolecular interfaces.

Solvent-controlled formation of alkali and alkali-earth-secured cucurbituril/guest trimers.

Cucurbit[7]uril (CB[7]) encapsulates adamantyl and trimethylsilyl substituents of positively charged guests in dimethyl sulfoxide (DMSO). Unlike in water or deuterium oxide, addition of a selection of alkali and alkali-earth cations with van der Waals radii between 1.0 and 1.4 Å (Na+, K+, Ca2+, Sr2+, Ba2+ and Eu3+) to the CB[7]/guest complexes triggers their cation-mediated trimerization, a process that is very slow on the nuclear magnetic resonance (NMR) time scale. Smaller (Li+, Mg2+) or larger cations (Rb+, Cs+ or NH4+) are inert. The trimers display extensive CH-O interactions between the equatorial and pseudo-equatorial hydrogens of CB[7] and the carbonyl rim of the neighboring CB[7] unit in the trimer, and a deeply nested cation between the three interacting carbonylated CB[7] rims; a counteranion is likely perched in the shallow cavity formed by the three outer walls of CB[7] in the trimer. Remarkably, a guest must occupy the cavity of CB[7] for trimerization to take place. Using a combination of semi-empirical and density functional theory techniques in conjunction with continuum solvation models, we showed that trimerization is favored in DMSO, and not in water, because the penalty for the partial desolvation of three of the six CB[7] portals upon aggregation into a trimer is less unfavorable in DMSO compared to water.

Cathode-Electrolyte Interface Modification by Binder Engineering for High-Performance Aqueous Zinc-Ion Batteries.

A stable cathode-electrolyte interface (CEI) is crucial for aqueous zinc-ion batteries (AZIBs), but it is less investigated. Commercial binder poly(vinylidene fluoride) (PVDF) is widely used without scrutinizing its suitability and cathode-electrolyte interface (CEI) in AZIBs. A water-soluble binder is developed that facilitated the in situ formation of a CEI protecting layer tuning the interfacial morphology. By combining a polysaccharide sodium alginate (SA) with a hydrophobic polytetrafluoroethylene (PTFE), the surface morphology, and charge storage kinetics can be confined from diffusion-dominated to capacitance-controlled processes. The underpinning mechanism investigates experimentally in both kinetic and thermodynamic perspectives demonstrate that the COO- from SA acts as an anionic polyelectrolyte facilitating the adsorption of Zn2+ ; meanwhile fluoride atoms on PTFE backbone provide hydrophobicity to break desolvation penalty. The hybrid binder is beneficial in providing a higher areal flux of Zn2+ at the CEI, where the Zn-Birnessite MnO2 battery with the hybrid binder exhibits an average specific capacity 45.6% higher than that with conventional PVDF binders; moreover, a reduced interface activation energy attained fosters a superior rate capability and a capacity retention of 99.1% in 1000 cycles. The hybrid binder also reduces the cost compared to the PVDF/NMP, which is a universal strategy to modify interface morphology.

From Induced-Fit Assemblies to Ternary Inclusion Complexes with Fullerenes in Corannulene-Based Molecular Tweezers.

The participation of the tether moiety in fullerene recognition of corannulene-based molecular tweezers is known to be an important factor. In the present work, we describe the synthesis of a set of fullerene receptors bearing two corannulene units located at a suitable distance to effectively interact with C60 and C70. The tether comprises a fluorene-like scaffold where an assortment of different groups with variable electronic properties has been grafted. The photophysical and electrochemical properties of all final compounds have been unveiled and correlated to the donor/acceptor (DA) nature of the tether. Despite these strong variations, their affinity toward fullerenes cannot be correlated in any way to simple DA behavior as the main contribution to the interaction correspond to London dispersion forces. We found, however, that the sulfur-derived subfamily is able to adapt better to the fullerene outer surface slightly increasing the charge transfer and electrostatic attractive interactions being the most outstanding example the case of thiophene 4-S with C70 as it is capable of forming a ternary 2:1 inclusion complex in solution with an electronic binding energy that offsets entropy and desolvation penalties typically associated with higher-order inclusion complexes.

Emerging rechargeable aqueous magnesium ion battery

Recently, aqueous rechargeable batteries have played an essential role in developing renewable energy due to the merits of low cost, high security, and high energy density. Among various aqueous-based batteries, aqueous magnesium ion batteries (AMIBs) have rich reserves and high theoretical specific capacity (3833 mAh cm −3 ). However, for future industrialization, AMIBs still face many scientific issues to be solved, such as the slow diffusion of magnesium ions in the material structure, the desolvation penalty at electrode-electrolyte interfaces, the cost of water-in-salt electrolyte, the low voltage of traditional aqueous electrolyte, etc. And yet a comprehensive summary of the components of AMIBs is lacking in the research community. This review mainly introduces the exploration and development of AMIB systems and related components. We conduct an in-depth study of the cathode materials appropriate for magnesium ion batteries from their crystal structures, focusing primarily on layered structures, spinel structures, tunnel structures, and three-dimensional framework structures. We also investigate the anode materials, ranging from inorganic materials to organic materials, as well as the electrolyte materials (from the traditional electrolyte to water-in-salt electrolyte). Finally, some perspectives on ensuing optimization design for future research efforts in the AMIBs field are summarized.

The FMO2 analysis of the ligand-receptor binding energy: the Biscarbene-Gold(I)/DNA G-Quadruplex case study.

In this work, the ab initio fragment molecular orbital (FMO) method was applied to calculate and analyze the binding energy of two biscarbene-Au(I) derivatives, [Au(9-methylcaffein-8-ylidene)2]+ and [Au(1,3-dimethylbenzimidazol-2-ylidene)2]+, to the DNA G-Quadruplex structure. The FMO2 binding energy considers the ligand-receptor complex as well as the isolated forms of energy-minimum state of ligand and receptor, providing a better description of ligand-receptor affinity compared with simple pair interaction energies (PIE). Our results highlight important features of the binding process of biscarbene-Au(I) derivatives to DNA G-Quadruplex, indicating that the total deformation-polarization energy and desolvation penalty of the ligands are the main terms destabilizing the binding. The pair interaction energy decomposition analysis (PIEDA) between ligand and nucleobases suggest that the main interaction terms are electrostatic and charge-transfer energies supporting the hypothesis that Au(I) ion can be involved in π-cation interactions further stabilizing the ligand-receptor complex. Moreover, the presence of polar groups on the carbene ring, as C = O, can improve the charge-transfer interaction with K+ ion. These findings can be employed to design new powerful biscarbene-Au(I) DNA-G quadruplex binders as promising anticancer drugs. The procedure described in this work can be applied to investigate any ligand-receptor system and is particularly useful when the binding process is strongly characterized by polarization, charge-transfer and dispersion interactions, properly evaluated by ab initio methods.

Application-Based Prospects for Dual-Ion Batteries.

Dual-ion batteries (DIBs) exhibit a distinct set of performance advantages and disadvantages due to their unique storage mechanism. However, the current cyclability/energy density tradeoffs of anion storage paired with the intrinsic required electrolyte loadings of conventional DIBs preclude their widespread adoption as an alternative to lithium-ion batteries (LIBs). Despite this, their reduced desolvation penalty and low-cost electrode materials may warrant their employment for low-temperature and/or grid storage applications. To expand beyond these applications, this Perspective reviews the prospects of solid salt storage and halogen intercalation-conversion as viable methods to increase DIB energy densities to a level on-par with LIBs. Fundamental limitations of conventional DIBs are examined, technology spaces are proposed where they can make meaningful impact over LIBs, and potential strategies are outlined to improve cell-level energy densities necessary for the widespread adoption of DIBs.

Achieving ultra-long lifespan Zn metal anodes by manipulating desolvation effect and Zn deposition orientation in a multiple cross-linked hydrogel electrolyte

Aqueous zinc-ion batteries (ZIBs) have received extensive attention due to the intrinsic advantages of high safety, low cost and environmental friendliness. But detrimental side reactions and dendrite problems resulting from high desolvation penalty and inhomogeneous Zn2+ flux at the interface severely hindered their practical applications. Herein, a novel polyacrylamide-poly (ethylene glycol) diacrylate-carboxymethyl cellulose (PMC) hydrogel electrolyte is designed to overcome these obstacles through reducing the desolvation energy barrier and guiding the preferential orientation of Zn deposition simultaneously. Theoretical calculation and experimental results reveal that the desolvation activation energy of the PMC hydrogel electrolyte (36.42 kJ mol−1) is substantially lower than that of conventional ZnSO4 aqueous electrolyte (62.31 kJ mol−1) due to the regulated Zn2+ solvation structure. Based on the high binding energy between amide groups and Zn2+, polymer chains in PMC also serve as facile Zn2+ transport channels to guide the uniform deposition behavior on the Zn (002) crystal surface, which is verified by the grazing incidence XRD analysis. Consequently, an ultra-long cycle life of 5000 h with a high coulombic efficiency of 99.5% is achieved by using the PMC hydrogel electrolyte. Considering the simple one-pot synthesizing method, the PMC hydrogel electrolyte provides new opportunities for developing practical ZIBs.

The many roles of solvent in homogeneous catalysis - The reductive amination showcase

In the global effort to fight climate change, the design and development of novel procedures for complex chemical multi-step reactions is essential for the transformation of chemical industry. The transformation of chemical production processes from petrochemicals towards renewable, sustainable feedstock and the identification of green solvent candidates require a careful assessment of the effects of solvent on thermodynamics and kinetics. As a prime example for the many roles of solvent in chemical catalysis, the reaction mechanism of the homogeneous rhodium-catalyzed reductive amination of 1-undecanal from plant oils with diethylamine forming the long-chain tertiary N,N-diethylundecylamine is investigated. The many roles of solvent during the course of a chemical reactions become apparent when direct substrate-solvent and catalyst-solvent interactions are considered and their polarization effects. Hydrogen bond forming solvent molecules promote the enamine intermediate formation in terms of thermodynamics and kinetics by actively participating as proton transfer agents but a de-solvation penalty for polar groups compromises the overall pathway. The sophisticated bidentate phosphine (SulfoXantPhos)RhH reducing catalyst controls the regioselectivity of the reaction by dedicated ligand-substrate interactions. Its activity is critically dependent on the strength of solvent coordination. The effect of solvent on the reaction rate becomes apparent from a solvent screening of the transition state of the rate-determining step and give a perspective on solvent control of rate constants in this complex multi-step reaction. Only in presence of an appropriate solvent, the calculated Gibbs free potential energy surface becomes shallow and flat and delivers thermodynamic and kinetic parameters in good agreement with experiment.

Beta turn propensity and a model polymer scaling exponent identify intrinsically disordered phase-separating proteins

The complex cellular milieu can spontaneously demix, or phase separate, in a process controlled in part by intrinsically disordered (ID) proteins. A protein's propensity to phase separate is thought to be driven by a preference for protein–protein over protein–solvent interactions. The hydrodynamic size of monomeric proteins, as quantified by the polymer scaling exponent (v), is driven by a similar balance. We hypothesized that mean v, as predicted by protein sequence, would be smaller for proteins with a strong propensity to phase separate. To test this hypothesis, we analyzed protein databases containing subsets of proteins that are folded, disordered, or disordered and known to spontaneously phase separate. We find that the phase-separating disordered proteins, on average, had lower calculated values of v compared with their non-phase-separating counterparts. Moreover, these proteins had a higher sequence-predicted propensity for β-turns. Using a simple, surface area-based model, we propose a physical mechanism for this difference: transient β-turn structures reduce the desolvation penalty of forming a protein-rich phase and increase exposure of atoms involved in π/sp2 valence electron interactions. By this mechanism, β-turns could act as energetically favored nucleation points, which may explain the increased propensity for turns in ID regions (IDRs) utilized biologically for phase separation. Phase-separating IDRs, non-phase-separating IDRs, and folded regions could be distinguished by combining v and β-turn propensity. Finally, we propose a new algorithm, ParSe (partition sequence), for predicting phase-separating protein regions, and which is able to accurately identify folded, disordered, and phase-separating protein regions based on the primary sequence.

Driving intercalation kinetic through hydrated Na+ insertion in V2O5 for high rate performance aqueous zinc ion batteries

V2O5, as a positive electrode material in aqueous zinc ion batteries, is easy to collapse in the process of repeated charging and discharging of Zn2+, thus leading to an inferior electrochemical performance. In this paper, hydrated Na+ has been inserted into the V2O5 layer by a simple hydrothermal method to synthesize NaxV2O5·nH2O (NaVO). Electrochemical characterization of NaVO is as follows, which has a capacity of 452 mA h g−1 at 100 mA g−1 and a capacity holding of 79% after 1000 cycles at 4 A g−1, indicating that the insertion of hydrated Na+ can efficiently enhance high-rate performance of V2O5 cathode. In-situ XRD tests have been employed to reveal the underlying mechanism of the superior electrochemical performance. It is certified that hydrated Na+ incorporation not only provides support pillars for V2O5 thereby improving the stability of V2O5 structure, but also significantly reduces the material’s desolvation penalty and enhances intercalation kinetics, which leads to a superior rate capability. These demonstrate the method that insertion of hydrated alkali metal ion into interlayer of nanomaterials is ideally suited for V-based material and other layered cathode materials for AZIBs.

Solvation, Speciation, and De-Solvation Penalties in Multivalent Battery Electrolytes

Although substantial effort has been applied to the development of new multivalent liquid electrolytes for next generation batteries, an improved understanding of how the solvation environment controls the properties of these electrolytes is needed. Most working electrolytes for Mg2+ and Ca2+ systems utilize low permittivity solvents, namely ethers, which enable the high charge density of the divalent cation to exert significant influence on the surrounding solvation environment. These effects lead to non-intuitive concentration-dependent speciation and significant ion correlations even when employing “weakly coordination” anions. In this presentation we describe the solvation environments of critical exemplar systems based on Ca2+, Mg2+, and Zn2+ working cations using complementary techniques, including dielectric relaxation spectroscopy and modeling. In select cases we connect these solvation details to electrochemical desolvation barriers through temperature-dependent impedance spectroscopy. Through these investigations we address critical questions regarding the magnitude and tunability of the dication desolvation penalty during metal deposition and/or cathode insertion.Sandia National Laboratories is a multimission laboratory managed and operated by National Technology & Engineering Solutions of Sandia, LLC, a wholly owned subsidiary of Honeywell International Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.

High‐Energy‐Density Quinone‐Based Electrodes with [Al(OTF)]2+ Storage Mechanism for Rechargeable Aqueous Aluminum Batteries

AbstractRechargeable aqueous aluminum batteries (AABs) are potential candidates for future large‐scale energy storage due to their large capacity and the high abundance of aluminum. However, AABs face the challenges of inferior rate capability and cycling life due to the high charge density of Al3+, which induces the sluggish intercalation/extraction dynamics and structure collapse of inorganic cathode materials during discharge–charge cycles. Here, the optimization of macrocyclic calix[4]quinone (C4Q) with a large cavity and multi‐adjacent carbonyls structure from quinone compounds to become excellent cathode materials for high‐energy‐density AABs is reported. It exhibits a high capacity of 400 mAh g−1, a high rate capability (300 mAh g−1 at 800 mA g−1), and an excellent low‐temperature performance (224 mAh g−1 at −20 °C). The combination of experiments and theoretical calculations proves that Al(OTF)2+ cations coordinate with the carbonyl groups of C4Q during the discharge process, which can reduce desolvation penalty. Moreover, the fabricated pouch‐type Al‐C4Q battery delivers an energy density of 93 Wh kg−1cell, showing great potential for large‐scale applications. This work is expected to facilitate the application of organic cathode for AABs.