Rechargeable Aqueous Zinc Batteries Research Articles

3D Leaf-Like Copper-Zinc Alloy Enables Dendrite-Free Zinc Anode for Ultra-Long Life Aqueous Zinc Batteries.

Metallic zinc exhibits immense potential as an anode material for aqueous rechargeable zinc batteries due to its high theoretical capacity, low redox potential, and inherent safety. However, practical applications are hindered by dendrite formation and poor cycling stability. Herein, a facile substitution reaction method is presented to fabricate a 3D leaf-like Cu@Zn composite anode. This unique architecture, featuring a 3D network of leaf-like Cu on a Zn foil surface, significantly reduces nucleation overpotential and facilitates uniform Zn plating/stripping, effectively suppressing dendrite growth. Notably, an alloy layer of CuZn5 forms in situ on the 3D Cu layer during cycling. DFT calculations reveal that this CuZn5 alloy possesses a lower Zn binding energy compared to both Cu and Zn metal, further promoting Zn plating/stripping and enhancing electrochemical kinetics. Consequently, the symmetric Cu@Zn electrode exhibits remarkable cycling stability, surpassing 1300 h at 0.5mA cm-2 with negligible dendrite formation. Furthermore, full cells comprising Cu@Zn||VO2 exhibit superior capacity and rate performance compared to bare Zn anodes. This work provides a promising strategy for constructing highly stable and efficient Zn anodes for next-generation aqueous zinc batteries.

A Water-in-Ester Electrolyte with Controllable Water Activity for Highly Reversible Zinc Anodes

Rechargeable aqueous zinc batteries, featuring intrinsic safety, low cost and terrific recyclability, are an emerging and engaging technology potentially for stationary energy storage. However, this technology is blocked by the instability of zinc anode/electrolyte interface, due to the water-induced hydrogen evolution and dendrite growth. Herein, we formulate a water-in-ester electrolyte to effectively regulate the water activity by controlling the molar ratio of H2O to γ-valerolactone. The γ-valerolactone gets in on the solvation of Zn2+ ions, helping to exclude almost all bound water molecules from the solvation shell, and interacts with free water via forming intermolecular hydrogen bonds, thus completely confining water molecules in γ-valerolactone network. Thanks to the constrained H2O molecules and the reduced water activity, Zn anodes exhibit heighted anti-corrosion abilities in the water-in-ester electrolyte compared with the pure water electrolyte. The zinc deposition morphology evolves from hexagonal dendrites to tense particles, as the pure water electrolyte is transformed to the water-in-ester electrolyte. Water-in-ester electrolytes as well promise less hydrogen production, and eventually improve the average columbic efficiency and cycling stability of asymmetric Zn ‖ Ti cell from less than 85% and merely 10 cycles to 99.6% and over 500 cycles. The cycling lifespan of symmetric Zn ‖ Zn cell is extended to more than 1100 h at 1 mA cm-2 and 1 mAh cm-2 with the water-in-ester electrolyte, fourfold higher than that of the pure water electrolyte. Additionally, superior full cell performance is demonstrated for the newly formulated electrolyte. This work sheds light on the strong correlation between water activity and performance of zinc anodes and contributes to developing more stable aqueous zinc batteries by restricting water activity.

Supramolecular Metal-Organic Framework for the High Stability of Aqueous Rechargeable Zinc Batteries.

Aqueous rechargeable Zn batteries (AZBs) are considered to be promising next-generation battery systems. However, the growth of Zn dendrites and water-induced side reactions have hindered their practical application, especially with regard to long-term cyclability. To address these challenges, we introduce a supramolecular metal-organic framework (SMOF) coating layer using an α-cyclodextrin-based MOF (α-CD-MOF-K) and a polymeric binder. The plate-like α-CD-MOF-K particles, combined with the polymeric binder create dense and homogeneous Zn2+ ion conductive pore channels that can vertically transport Zn2+ ions through the cavity while restricting the contact of water molecules. Molecular dynamics (MD) simulation verifies that Zn2+ ions can reversibly migrate through the pores of α-CD-MOF-K by partial dehydration. The uniform Zn deposition/dissolution promotes a smooth solid-electrolyte interface layer on the Zn metal anode and effectively suppresses side reactions with free water molecules. The α-CD-MOF-K@Zn symmetric cell exhibits stable cycling and a small polarization voltage of 70 mV for 800 h at 5 mA cm-2, and the α-CD-MOF-K@Zn|α-MnO2 full cell shows only 0.12% capacity decay per cycle at a rate of 1 A g-1.

A water-in-lactone electrolyte with controllable water activity for highly reversible zinc anodes

Rechargeable aqueous zinc batteries, offering the advantages of intrinsic safety, affordability, and superior recyclability, represent an emerging technology for stationary energy storage. However, the practical application of the technology is fundamentally blocked by the instability of the zinc anode/electrolyte interface caused by the water-induced hydrogen evolution reaction and Zn dendrite growth. Here, we formulate a water-in-lactone electrolyte to effectively regulate the water activity by adjusting the molar ratio of H2O to green γ-valerolactone. The γ-valerolactone not only enters the solvation shell of Zn2+ ions, excluding nearly all bound water molecules, but also interacts with free water via forming intermolecular hydrogen bonds, thus completely confining water molecules within γ-valerolactone network. As a result, the water-in-lactone electrolyte minimizes hydrogen evolution side reactions and promotes uniform zinc electrodeposition. The coulombic efficiency of Zn ‖ Ti asymmetric cells is improved to 99.6 % over 500 cycles at a current density of 1 mA cm−2 and an areal capacity of 1 mAh cm−2. The cycling lifespan of Zn ‖ Zn symmetric cells is extended to more than 1100 h with the water-in-lactone electrolyte, much higher than that with the pure water electrolyte (less than 250 h). When coupled with polyaniline cathodes, Zn full cells utilizing the newly formulated electrolyte demonstrate enhanced cycling stability with a capacity retention of 73 % after ∼500 cycles at 200 mA g−1. Moreover, the water-in-lactone electrolyte enhances the temperature tolerance of Zn ion capacitors with activated carbon cathodes, allowing stable operation from −20 ℃ to 80 ℃. This work further sheds light on the significant correlation between water activity and the performance of zinc anodes, and hopefully contributes to the advancement of stable aqueous zinc batteries.

Integrated Hydrogel-Zn Structure with Modified Interface Realizing Fast Ion Transfer for Long Cycling Zn-ion Battery

Fabrication of gel electrolytes are effective strategy to solve the side reactions and dendrite growth of Zn anodes in aqueous rechargeable zinc batteries (ARZBs). However, complicated synthesis and ex-situ assembled processes lead to poor electrode–electrolyte interfacial contact, which hinders ion transfer. Herein, compatible and stable electrode–electrolyte structure is constructed by in-situ polymerization process. The tightly coupled electrode–electrolyte interface reduces the mass transfer impedance, balances electric field distribution, and thus inhibits dendrites. What’s more, the −SO3H groups in gel electrolyte play a significant role which performs as cation transport channels to regulate the deposition behavior of Zn along (002) crystal plane. The intercanected and porous structure of this electrolyte promote the desolvation process of [Zn(H2O)6]2+ and inhibit the side reaction. As a result, the symmetric cell exhibits ultra-long lifespan over 4,530 h (＞188 days), Zn||Cu cell delivers an average coulombic efficiency (CE) of 99.85 % with 1,000 cycles. Zn||MVO cell operates stably for over 2,700 cycles with CE of 99.91 %. This integrated hydrogel-Zn structure provides broad application prospect in wearable devices.

Self-regulating shielding layer induces (002) plane directional deposition of zinc metal anode

Rechargeable aqueous zinc batteries (AZIBs) are ideal for grid-scale energy storage due to their safety and economic characteristics. However, uncontrollable side reactions and dendrite growth severely affect the reversibility of zinc anodes. In the interfacial reaction, inducing smooth deposition of dominant planes is crucial for stabilizing the zinc anodes. Herein, we report a highly concentrated 1‑butyl‑3-methylimidazolium ion (BMIM+) modified electrolyte to improve the diffusion and deposition behavior of Zn2+. Thanks to the strong adsorption effect of BMIM+ at the zinc anode interface, the self-regulating shielding layer inhibits water-induced parasitic reactions. Under the action of BMIM+, Zn2+ has the lowest diffusion energy barrier towards the (002) plane, thus transforming the electrodeposition from a randomly stacked sheet to a dense deposited layer in the Zn(002) plane. The results showed that the symmetric cell composed of the modified electrolyte had a cycle life of 3200 h at 1 mA cm−2, and the average coulombic efficiency (CE) of the asymmetric cell was as high as 99.8 %. The full cell assembled with ZnxV2O5·nH2O still provided 86 % capacity retention at 2 A g−1 after 500 cycles. This electrolyte modification strategy provides a promising option for modulating the anode/electrolyte interface chemistry to achieve high-performance AZIBs.

Dendrite‐Free Zn Metal Anodes with Boosted Stability Achieved by Four‐in‐One Functional Additive in Aqueous Rechargeable Zinc Batteries

Dendrite‐Free Zn Metal Anodes with Boosted Stability Achieved by Four‐in‐One Functional Additive in Aqueous Rechargeable Zinc Batteries

Converting Commercial Zn Foils into Single (002)‐Textured Zn with Millimeter‐Sized Grains for Highly Reversible Aqueous Zinc Batteries

AbstractRechargeable aqueous zinc batteries are promising but hindered by unfavorable dendrite growth and side reactions on zinc anodes. In this study, we demonstrate a fast melting‐solidification approach for effectively converting commercial Zn foils into single (002)‐textured Zn featuring millimeter‐sized grains. The melting process eliminates initial texture, residual stress, and grain size variations in diverse commercial Zn foils, guaranteeing the uniformity of commercial Zn foils into single (002)‐textured Zn. The single (002)‐texture ensures large‐scale epitaxial and dense Zn deposition, while the reduction in grain boundaries significantly minimizes intergranular reactions. These features enable large grain single (002)‐textured Zn shows planar and dense Zn deposition under harsh conditions (100 mA cm−2, 100 mAh cm−2), impressive reversibility in Zn||Zn symmetric cell (3280 h under 1 mA cm−2, 830 h under 10 mAh cm−2), and long cycling stability over 180 h with a high depth of discharge value of 75 %. This study successfully addresses the issue of uncontrollable texture formation in Zn foils following routine annealing treatments with temperatures below the Zn melting point. The findings of this study establish a highly efficient strategy for fabricating highly reversible single (002)‐textured Zn anodes.

Converting Commercial Zn Foils into Single (002)-Textured Zn with Millimeter-Sized Grains for Highly Reversible Aqueous Zinc Batteries.

Rechargeable aqueous zinc batteries are promising but hindered by unfavorable dendrite growth and side reactions on zinc anodes. In this study, we demonstrate a fast melting-solidification approach for effectively converting commercial Zn foils into single (002)-textured Zn featuring millimeter-sized grains. The melting process eliminates initial texture, residual stress, and grain size variations in diverse commercial Zn foils, guaranteeing the uniformity of commercial Zn foils into single (002)-textured Zn. The single (002)-texture ensures large-scale epitaxial and dense Zn deposition, while the reduction in grain boundaries significantly minimizes intergranular reactions. These features enable large grain single (002)-textured Zn shows planar and dense Zn deposition under harsh conditions (100 mA cm-2, 100 mAh cm-2), impressive reversibility in Zn||Zn symmetric cell (3280 h under 1 mA cm-2, 830 h under 10 mAh cm-2), and long cycling stability over 180 h with a high depth of discharge value of 75 %. This study successfully addresses the issue of uncontrollable texture formation in Zn foils following routine annealing treatments with temperatures below the Zn melting point. The findings of this study establish a highly efficient strategy for fabricating highly reversible single (002)-textured Zn anodes.

Enhanced electrocatalytic conversion of tellurium with MnO hollow nanospheres modified hierarchical n-doped carbon nanosheets in high-performance aqueous Zn-Te battery

Rechargeable aqueous zinc batteries (AZBs) are increasingly recognized as an alternative to conventional energy storage systems due to their environmentally safe nature, abundant zinc resources, and high theoretical capacity. However, the intercalation or surface redox mechanisms limit the development of AZBs cathode materials due to low specific capacity and energy density. The tellurium-based (Te) materials with conversion mechanisms are promising cathode materials for AZBs. Nevertheless, the slow kinetics are detrimental to the increase in specific capacity and energy density for Zn-Te battery. Therefore, a hierarchical structure of manganese oxide (MnO) hollow nanospheres loaded on nitrogen-doped carbon nanosheets (MnO@NC) was rationally designed and used as Te hosts (Te/MnO@NC) for Zn-Te battery. This hierarchical structure facilitates the loading of more Te species. Meanwhile, the MnO hollow nanospheres can expose more active sites, which can promote the kinetics of Te redox reactions thereby lowering the reaction energy barrier. The Te/MnO@NC cathode exhibits high specific capacity and high energy density (429 mAh g−1 and 407 Wh Kg−1 at 0.1 A g−1). Additionally, the conversion mechanism was investigated by systematic characterization and density functional theory (DFT) calculations. This study presents a new design platform for developing AZBs with high specific capacity and energy density.

A High-Energy Tellurium Redox-Amphoteric Conversion Cathode Chemistry for Aqueous Zinc Batteries.

Rechargeable aqueous zinc batteries are potential candidates for sustainable energy storage systems at a grid scale, owing to their high safety and low cost. However, the existing cathode chemistries exhibit restricted energy density, which hinders their extensive applications. Here, a tellurium redox-amphoteric conversion cathode chemistry is presented for aqueous zinc batteries, which delivers a specific capacity of 1223.9 mAh gTe -1 and a high energy density of 1028.0Wh kgTe -1. A highly concentrated electrolyte (30mol kg-1 ZnCl2) is revealed crucial for initiating the Te redox-amphoteric conversion as it suppresses the H2O reactivity and inhibits undesirable hydrolysis of the Te4+ product. By carrying out multiple operando/ex situ characterizations, the reversible six-electron Te2-/Te0/Te4+ conversion with TeCl4 is identified as the fully charged product and ZnTe as the fully discharged product. This finding not only enriches the conversion-type battery chemistries but also establishes a critical step in exploring redox-amphoteric materials for aqueous zinc batteries and beyond.

Atomic-scale inorganic carbon additive with rich surface polarity and low lattice mismatch for zinc to boost Zn metal anode reversibility

The renaissance of aqueous zinc-ion batteries (ZIBs) is impeded by the disordered Zn deposition and notorious water attack at the Zn-electrolyte interface. Electrolyte additive engineering plays a vital role in tuning the electrode–electrolyte interface chemistry to stabilize Zn anode but its long-term performance at high plating/stripping rates and capacities remains a challenge. Herein, we demonstrate highly reversible Zn anodes by employing the atomic-scale inorganic carbon nanomaterials (ICN) as a multifunctional electrolyte additive into the common ZnSO4 solution to regulate the Zn deposition behaviors. The ICN with rich surface polar groups modulates the primary Zn2+ solvation structure to avoid the side reactions, and preferentially absorbs on the Zn anode surface to build a passivated-protect interface to suppress Zn corrosion and dendrite growth. More importantly, its low lattice mismatch with zinc navigates the preferred Zn (002) deposition to induce smooth and dense Zn plating morphology, fundamentally eradicating the Zn dendrite issues and further Zn corrosion. Consequently, the electrolyte containing ICN additive endows the symmetric Zn cells with fabulous cumulative capacity (3500 mAh cm−2), decent Coulombic efficiency (99.69 %) at 10 mA cm−2, and excellent stability of 800 cycles with only 0.022 % capacity decay per cycle in the Zn||VOX battery under practical conditions of limited Zn supply, high-loading cathode and lean electrolyte. This work presents an effective strategy to advance the practical applications of rechargeable aqueous zinc batteries.

Fast Reaction Kinetics and Commendable Low‐Temperature Adaptability of Zinc Batteries Enabled by Aprotic Water‐Acetamide Symbiotic Solvation Sheath

AbstractAlthough rechargeable aqueous zinc batteries are cost effectiveness, intrinsicly safe, and high activity, they are also known for bringing rampant hydrogen evolution reaction and corrosion. While eutectic electrolytes can effectively eliminate these issues, its high viscosity severely reduces the mobility of Zn2+ ions and exhibits poor temperature adaptability. Here, we infuse acetamide molecules with Lewis base and hydrogen bond donors into a solvated shell of Zn[(H2O)6]2+ to create Zn(H2O)3(ace)(BF4)2. The viscosity of 1ace‐1H2O is 0.032 Pa s, significantly lower than that of 1ace‐0H2O (995.6 Pa s), which improves ionic conductivity (9.56 mS cm−1) and shows lower freezing point of −45 °C, as opposed to 1ace‐0H2O of 4.04 mS cm−1 and 12 °C, respectively. The acidity of 1ace‐1H2O is ≈2.8, higher than 0ace‐1H2O at ≈0.76, making side reactions less likely. Furthermore, benefiting from the ZnCO3/ZnF2‐rich organic/inorganic solid electrolyte interface, the Zn || Zn cells cycle more than 1300 hours at 1 mA cm−2, and the Zn || Cu operated over 1800 cycles with an average Coulomb efficiency of ≈99.8 %. The Zn || PANI cell cycled over 8500 cycles, with a specific capacity of 99.8 mAh g−1 at 5 A g−1 at room temperature, and operated at −40 °C with a capacity of 66.8 mAh g−1.

Fast Reaction Kinetics and Commendable Low-Temperature Adaptability of Zinc Batteries Enabled by Aprotic Water-Acetamide Symbiotic Solvation Sheath.

Although rechargeable aqueous zinc batteries are cost effectiveness, intrinsicly safe, and high activity, they are also known for bringing rampant hydrogen evolution reaction and corrosion. While eutectic electrolytes can effectively eliminate these issues, its high viscosity severely reduces the mobility of Zn2+ ions and exhibits poor temperature adaptability. Here, we infuse acetamide molecules with Lewis base and hydrogen bond donors into a solvated shell of Zn[(H2 O)6 ]2+ to create Zn(H2 O)3 (ace)(BF4 )2 . The viscosity of 1ace-1H2 O is 0.032 Pa s, significantly lower than that of 1ace-0H2 O (995.6 Pa s), which improves ionic conductivity (9.56 mS cm-1 ) and shows lower freezing point of -45 °C, as opposed to 1ace-0H2 O of 4.04 mS cm-1 and 12 °C, respectively. The acidity of 1ace-1H2 O is ≈2.8, higher than 0ace-1H2 O at ≈0.76, making side reactions less likely. Furthermore, benefiting from the ZnCO3 /ZnF2 -rich organic/inorganic solid electrolyte interface, the Zn || Zn cells cycle more than 1300 hours at 1 mA cm-2 , and the Zn || Cu operated over 1800 cycles with an average Coulomb efficiency of ≈99.8 %. The Zn || PANI cell cycled over 8500 cycles, with a specific capacity of 99.8 mAh g-1 at 5 A g-1 at room temperature, and operated at -40 °C with a capacity of 66.8 mAh g-1 .

Fused Functional Organic Material with the Alternating Conjugation of Quinone-Pyrazine as Cathode for Aqueous Zinc Ion Batteries.

Organic cathode materials for aqueous rechargeable zinc batteries (ARZBs) are rapidly gaining prominence, while the exploration of compounds with affordable synthesis, satisfactory electrochemical performance, and understandable mechanisms still remains challenging. In this study, 6,8,15,17-tetraaza-heptacene-5,7,9,14,16,18-hexaone (TAHQ) as an easily synthesized organic cathode material with novel quinone/pyrazine alternately conjugated molecule structure is presented. This organic electrode exhibits good capacity with highly reversible redox reactions, and the influence of multi-active structures on the Zn2+/H+ loading behavior is systematically investigated by ex situ spectroscopy, electrochemical tests, and computation. Both experimental and theoretical studies effectively address the Zn2+/H+ intercalation/deintercalation kinetics. Benefitting from the fused active functionalities, the assembled Zn//TAHQ battery displays a maximum discharge specific capacity of 254.3mAhg-1 at 0.5Ag-1, and it maintains remarkable cycle performance with 71% capacity retention after 1000 cycles under 5Ag-1.

Enhanced kinetics and stability for aqueous Zn battery enabled by low-cost additive chemistry

Rechargeable aqueous zinc(Zn) batteries are a sustainable alternative to lithium-based energy storage devices due to their high safety, low cost, and scalability. Unfortunately, the Zn/Zn2+ redox chemistry is significantly plagued by undesirable interface caused by the instability of water, which directly dictates the low Zn reversibility and dendrite growth behavior. Here, we report an aqueous electrolyte in which low-cost ammonium dihydrogen phosphate is utilized as an electrolyte additive to enable the in-situ construction of phosphate-based interphase on the Zn-metal surface. Importantly, such interphase not only effectively eliminates water-related parasitic reactions and enables a highly reversible Zn deposition/dissolution, as demonstrated by its high Coulombic efficiency of 99.3 %, but also contributes a dendrite-free Zn morphology. Apart from the improved stability of the Zn anode, the addition of NH4H2PO4 also grants the enhanced reaction kinetics of Zn2+, bringing a lower Zn2+ de-solvation energy barrier and much-improved rate performance. Benefiting from the synergistic factors, excellent cycling performances of the Zn0.25V2O5·nH2O (ZVO)/Zn batteries are guaranteed. Additionally, a 31.2 mAh ZVO/Zn pouch cell also demonstrates a stable long life of 400 cycles, and capacity retention of 67.8 % is also retained. The low-cost and efficient electrolyte strategy points out a promising direction for practical Zn batteries.

Regulating the multi-metal-sulfur bonds in the layered double hydroxide crystalline structure for rechargeable aqueous zinc batteries and supercapacitors

Layered double hydroxide (LDH) electrodes usually suffer from the limitations like unsatisfactory conductivity and electrochemical reversibility. Therefore, a novel and feasible method of introducing multi-metal-sulfur bonds in the main LDH crystalline structure, especially the Cu-S bonds, has been proposed and designed in this work. According to the experimental and theoretical analysis, the multi-metal-sulfur bonds could remarkably improve the electrochemical reversibility, activity and electrical conductivity of the LDH-based electrode. In addition, the designed material synthesis method could greatly enhance the specific surface area of the electrode, and via the subtle modulation of the copper and sulfur adulteration, the crystalline degree and the metal composition could be effectively adjusted. The prepared C/N-NiCoMnCu-LDH/S hollow structures (C/N-NCMC/S) possess a high specific capacitance of 1742 F g−1 at 1 A g−1 and could retain 68.6% of the capacitance at 20 A g−1. As for the assembled zinc battery, a specific capacity of 203.6 mAh g−1 could be achieved at 1 A g−1 and 74% of the capacity could be retained after 1500 cycles. Additionally, the hybrid supercapacitor delivers a super-long cycling stability of 98.1% capacitance retention after 40,000 cycles. Moreover, the battery and the supercapacitor present high energy densities of 127.2 and 41.4 Wh kg−1, respectively.

High Performance Zinc-Based Anodes for Aqueous Zinc Batteries

In the past thirty years, there has been significant development in the search for alternative energy sources such as secondary battery systems. Zinc (fourth-most mined material) has attracted much attention due to its abundance, low-cost, and recyclability. Moreover, as zinc-based batteries can be manufactured with aqueous-based electrolytes that benefits from many advantages of Zn anode, such as low redox protentional (-0.76V vs SHE), high theoretical capacity (820mAh/g), and enhanced safety. These features allow for high applicability in large-scale stationary energy storage system. Zinc-based batteries (MnO2/Zinc) have been previously commercialized and are one of the dominant technologies in the primary battery market. However, the alkaline MnO2/Zn battery is not currently considered re-chargeable due to the formation of zinc-dendrites, passivation of Zn metal, and cathode poisoning. In contrast to the alkaline system, the mild acidic system does not suffer from zinc passivation as there is negligible generation of zinc oxide/zinc hydroxide.In this work, we report a proof-of concept work where electrodeposited zinc-based anodes (zinc and zinc-alloys) are used in mild acidic aqueous electrolyte. The study provides a comparison of commercial zinc foil, and electrodeposited zinc/zinc-alloy. The anodes are further analyzed structurally through X-ray diffraction and scanning electron microscopy. To evaluate the feasibility of each anode. further electrochemical characterization was carried out in coin cells as symmetric and full cells. The electrodeposited zinc-based anodes exhibit low electrode polarization (~0.030-0.045V), and more stable cycling performance at 10 mA cm-2 compared to commercial zinc foil. Furthermore, full cells with an electrodeposited zinc or zinc-alloy anode, DTT cathode, in 2M ZnSO4 delivered comparable capacities but higher stability compared to commercial zinc. Consequently, this work points toward a further development for anode materials in rechargeable aqueous zinc batteries for scalable applications.

Enhancing Temperature Adaptability of Aqueous Zinc Batteries via Antifreezing Electrolyte and Site-Selective ZnSe-Ag Interface Layer Design.

Rechargeable aqueous zinc batteries (RAZBs) represent a sustainable, environmentally benign, cost-efficient energy storage solution for the scaled renewable power system. However, the cycling endurance and temperature adaptability of RAZBs are hindered by practical technological barriers such as the subzero freezing point of aqueous electrolyte, severe cation dissolution of the cathode, and dendrite growth on the Zn anode. Herein, we optimize the hybrid electrolyte formulation of 8 M ZnCl2 in the ethylene glycol-water mixed solvent to reconfigure the hydrogen bonding and [Zn(H2O)1.80(EG)0.23]2+ solvation sheath, which well balances the ionic conductivity and the antifreezing property until -125 °C. As monitored by operando X-ray diffraction, meanwhile, the structural dissolution of the V2O5 cathode upon the dynamic cycling and static idling storage at elevated temperature are effectively restrained. At the anode side, the thermally induced substitution between the Ag2Se overcoating and Zn foil in situ constructs the site-selective, mosaic interface layer, in which the solvophilic ZnSe facilitates the desolvation, while the Ag species provide zincophilic nucleation sites for high-throughput Zn deposition. The synergistic coupling of the antifreezing electrolyte and anode interfacial design enables the wide-temperature-range adaptability of the RAZB prototype (10 μm Zn foil and 1 mAh cm-2 V2O5 cathode), which balances the cycling endurance (92.5% capacity retention rate for 1000 cycles), 84.7% mitigation of the self-discharge rate at 55 °C, as well as the secured cyclability even at -40 °C.

Metal–Organic Framework‐Derived MnO Nanocrystals Embedded in a Spindle Carbon for Rechargeable Aqueous Zinc Battery with a Molten Hydrate Electrolyte

Rechargeable aqueous zinc batteries (RAZBs) are emerging candidates for large‐scale energy storage. However, the lack of high‐capacity cathodes because of the electrostatic interactions between Zn2+ and cathode and the inferior electronic conductivity restricts their performance. The operating voltage limitation imposed by water is another barrier for RAZBs. Herein, manganese oxide (MnO) nanocrystals embedded in a spindle carbon matrix (MnO@C) synthesized from a metal–organic framework are used as a cathode. The uniform distribution of fine‐sized MnO (≈100 nm) in the carbonized matrix (≈5 μm) and the intimate connection between them not only increase the utilization of electroactive material but also eliminate the use of conductive additive. By utilizing the molten hydrate electrolyte, ZnCl2·2.33H2O, a discharge voltage plateau approaching 1.60 V and a high reversible capacity of 106 mAh g−1 after 200 cycles are achieved. This research proposes an approach for affordable RAZBs to fulfill large‐scale energy storage.