Zn Dendrites Research Articles

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.

High-voltage and dendrite-free zinc-iodine flow battery

Zn-I2 flow batteries, with a standard voltage of 1.29 V based on the redox potential gap between the Zn2+-negolyte (−0.76 vs. SHE) and I2-posolyte (0.53 vs. SHE), are gaining attention for their safety, sustainability, and environmental-friendliness. However, the significant growth of Zn dendrites and the formation of dead Zn generally prevent them from being cycled at high current density (>80 mA cm−2). In addition, the crossover of Zn2+ across cation-exchange-membrane also limits their cycle stability. Herein, we propose a chelated Zn(P2O7)26- (donated as Zn(PPi)26-) negolyte, which facilitates dendrite-free Zn plating and effectively prevents Zn2+ crossover. Remarkably, the utilization of chelated Zn(PPi)26- as a negolyte shifts the Zn2+/Zn plating/stripping potential to −1.08 V (vs. SHE), increasing cell voltage to 1.61 V. Such high voltage Zn-I2 flow battery shows a promising stability over 250 cycles at a high current density of 200 mA cm−2, and a high power density up to 606.5 mW cm−2.

Gel biopolymer electrolyte for high-voltage, durable, and flexible Zn/K dual-ion pouch cells

Zinc-ion rechargeable battery (ZIRB) is a promising candidate for future energy storage systems due to its cost-effectiveness, operational safety, and environmental friendliness. However, the commercial-scale application of ZIRB is hindered by its insufficient energy efficiency, poor rate capability, and inferior cycling stability. Here, we introduce a gel biopolymer electrolyte (GBE) empowered Zn/K dual-ion battery with exceptional cycling and rate performance. Calling for sustainability, this cellulose-encapsulated bisalt electrolyte presents strong mechanical robustness that inhibits Zn dendrite growth and promotes anodic plating/stripping reversibility. Sandwiching the GBE between a potassium manganese hexacyanoferrate (KMnHCF) cathode and a Zn anode, the coin-cell configuration of KMnHCF|GBE|Zn demonstrates a high voltage discharge plateau of 1.80 V, an initial capacity of up to 65 mAh g−1, and excellent cycling stability with capacity retention of 92 % after 1,000 cycles. Furthermore, the superior durability, flexibility, safety, and endurance with extreme conditions (e.g., bending, puncturing, and cutting) demonstrated by KMnHCF|GBE|Zn pouch-cell enables its future application in wearable electronics.

Trace Small Molecular/Nano-Colloidal Multiscale Electrolyte Additives Enable Ultra-Long Lifespan of Zinc Metal Anodes.

Electrolyte additives are efficient to improve the performance of aqueous zinc-ion batteries (AZIBs), yet the current electrolyte additives are limited to fully water-soluble additives (FWAs) and water-insoluble additives (WIAs). Herein, trace slightly water-soluble additives (SWAs) of zinc acetylacetonate (ZAA) were introduced to aqueous ZnSO4 electrolytes. The SWA system of ZAA is composed of a FWA part and a WIA part in a dynamic manner of dissolution equilibrium. The FWA part exists as soluble small molecules, which efficiently regulate Zn2+ ion solvation structure, while the WIA part exists as insoluble nano-colloids, which in-situ form a thick and robust solid electrolyte interface film on zinc metal anodes (ZMAs). Such small molecular/nano-colloidal multiscale electrolyte additives of ZAA are capable to not only improve ionic conductivity and transference number but also inhibit corrosion, hydrogen evolution, and Zn dendrite on ZMAs. The SWA-based Zn∥Zn half battery delivers a superb cumulative plating capacity of 15 Ah cm-2 under 1 mAh cm-2 and 20 mA cm-2, and the SWA-based NH4V4O10∥Zn pouch cell obtains a capacity retention of 67.8% within 4000 cycles under 4 A g-1. The study provides innovative insights for rational design of electrolyte additives, which may pave the way for the practicality of AZIBs.

Mass Transfer Limitation within Molecular Crowding Electrolyte Reorienting (100) and (101) Texture for Dendrite‐Free Zinc Metal Batteries

AbstractAqueous zinc metal batteries are emerging as a promising alternative for energy storage due to their high safety and low cost. However, their development is hindered by the formation of Zn dendrites and side reactions. Herein, a macromolecular crowding electrolyte (MCE40) is prepared by incorporating polyvinylpyrrolidone (PVP) into the aqueous solutions, exhibiting an enlarged electrochemical stability window and anti‐freezing properties. Notably, through electrochemical measurements and characterizations, it is discovered that the mass transfer limitation near the electrode surface within the MCE40 electrolyte inhibits the (002) facets. This leads to the crystallographic reorientation of Zn deposition to expose the (100) and (101) textures, which undergo a “nucleation‐merge‐growth” process to form a uniform and compact Zn deposition. Consequently, the MCE40 enables highly reversible and stable Zn plating/stripping in Zn/Cu half cells over 600 cycles and in Zn/Zn symmetric cells for over 3000 hours at 1.0 mA cm−2. Furthermore, Na0.33V2O5/Zn and α‐MnO2/Zn full cells display promising capacity and sustained stability over 500 cycles at room and sub‐zero temperatures. This study highlights a novel electrochemical mechanism for achieving preferential Zn deposition, introducing a unique strategy for fabricating dendrite‐free zinc metal batteries.

A Stable High-Performance Zn-Ion Batteries Enabled by Highly Compatible Polar Co-Solvent.

Uncontrollable growth of Zn dendrites, irreversible dissolution of cathode material and solidification of aqueous electrolyte at low temperatures severely restrict the development of aqueous Zn-ion batteries. In this work, 2,2,2-trifluoroethanol (TFEA) with a volume fraction of 50% as a highly compatible polar-solvent is introduced to 1.3M Zn(CF3SO3)2 aqueous electrolyte, achieving stable high-performance Zn-ion batteries. Massive theoretical calculations and characterization analysis demonstrate that TFEA weakens the tip effect of Zn anode and restrains the growth of Zn dendrites due to electrostatic adsorption and coordinate with H2O to disrupt the hydrogen bonding network in water. Furthermore, TFEA increases the wettability of the cathode and alleviates the dissolution of V2O5, thus improving the capacity of the full battery. Based on those positive effects of TFEA on Zn anode, V2O5 cathode, and aqueous electrolyte, the Zn//Zn symmetric cell delivers a long cycle-life of 782h at 5mAcm-2 and 2mAhcm-2. The full battery still declares an initial capacity of 116.78mAhg-1, and persists 87.73% capacity in 2000 cycles at -25 °C. This work presents an effective strategy for fully compatible co-solvent to promote the stability of Zn anode, V2O5 cathode and aqueous electrolyte for high-performance Zn-ion batteries.

Mass Transfer Limitation within Molecular Crowding Electrolyte Reorienting (100) and (101) Texture for Dendrite-Free Zinc Metal Batteries.

Aqueous zinc metal batteries are emerging as a promising alternative for energy storage due to their high safety and low cost. However, their development is hindered by the formation of Zn dendrites and side reactions. Herein, a macromolecular crowding electrolyte (MCE40) is prepared by incorporating polyvinylpyrrolidone (PVP) into the aqueous solutions, exhibiting an enlarged electrochemical stability window and anti-freezing properties. Notably, through electrochemical measurements and characterizations, it is discovered that the mass transfer limitation near the electrode surface within the MCE40 electrolyte inhibits the (002) facets. This leads to the crystallographic reorientation of Zn deposition to expose the (100) and (101) textures, which undergo a "nucleation-merge-growth" process to form a uniform and compact Zn deposition. Consequently, the MCE40 enables highly reversible and stable Zn plating/stripping in Zn/Cu half cells over 600 cycles and in Zn/Zn symmetric cells for over 3000 hours at 1.0 mA cm-2. Furthermore, Na0.33V2O5/Zn and α-MnO2/Zn full cells display promising capacity and sustained stability over 500 cycles at room and sub-zero temperatures. This study highlights a novel electrochemical mechanism for achieving preferential Zn deposition, introducing a unique strategy for fabricating dendrite-free zinc metal batteries.

Solidify Eutectic Electrolytes via the Added MXene as Nucleation Sites for a Solid-State Zinc-Ion Battery with Reconstructed Ion Transport.

Stationary energy storage infrastructure based on zinc-ion transport and storage chemistry is attracting more attention due to favorable metrics, including cost, safety, and recycling feasibility. However, splitting water and liquid electrolyte fluidity lead to cathode dissolution and Zn corrosion, resulting in rapid attenuation of the capacity and service life. Herein, a new architecture of solid-state electrolytes with high zinc ionic conductivity at room temperature was prepared via solidification of deep eutectic solvents utilizing MXene as nucleation additives. The ionic conductivity of MXene/ZCEs reached 6.69 × 10-4 S cm-1 at room temperature. Dendrite-free Zn plating/stripping with high reversibility can remain for over 2500 h. Subsequently, the fabricated solid-state zinc-ion battery with eliminated HER and suppressed Zn dendrites exhibited excellent cycling performance and could work normally in a range from -10 to 60 °C. This design inspired by eutectic solidification affords new insights into the multivalent solid electrochemistry suffering from slow ion migration.

Construction of a Composite Sn‐DLC Artificial Protective Layer with Hierarchical Interfacial Coupling Based on Gradient Coating Technology Toward Robust Anodes for Zn Metal Batteries

AbstractDeveloping a robust zinc (Zn) anode, free from Zn dendrites and unwanted side reactions, relies on designing a durable and efficient interfacial protection layer. In this study, gradient coating technology is employed to construct a hierarchically structured composite of Sn with diamond‐like carbon (DLC/Sn‐DLC) as an artificial protective layer. The DLC framework endows DLC/Sn‐DLC layer with high stability and adaptability, achieving long‐term stability of the anode–electrolyte interface. The gradual‐composite Sn, with its Sn─O─C interface chemical bonds, facilitates rapid charge transfer and offers ample zincophilic sites at the base, promoting uniform Zn2+ reduction reaction and deposition. Additionally, the DLC/Sn‐DLC composite exhibits a “lotus effect” and favorable hydrophobic properties, preventing water‐reduced side reactions. Leveraging this structural design and the synergistic cooperation of DLC and Sn, the DLC/Sn‐DLC@Zn electrode demonstrates remarkable Zn plating/stripping reversibility, eliminating Zn dendrites and side reactions. Notably, under a high current density of 10 mA cm−2, the DLC/Sn‐DLC@Zn anode‐based symmetrical cell exhibits stable operation for over 1550 h, with a low nucleation overpotential of 101 mV. The DLC/Sn‐DLC@Zn||Mn3O4‐CNTs full battery delivers a high capacity of 109.8 mAh cm−2 after 5800 cycles at 2 A g−1, and the pouch cell shows potential for energy storage applications.

The zinc ion concentration dynamically regulated by an ionophore in the outer Helmholtz layer for stable Zn anode

The Zn dendrite limits the practical application of aqueous zinc-ion batteries in the large-scale energy storage systems. To suppress the growth of Zn dendrites, a zinc ionophore of hydroxychloroquine (defined as HCQ) applied in vivo treatment is investigated as the electrolyte additive. HCQ dynamically regulates zinc ion concentration in the outer Helmholtz layer, promoting even Zn plating at the anode/electrolyte interface. This is evidenced by the scanning electron microscopy, which delivers planar Zn plating after cycling. It is further supported by the X-ray diffraction spectroscopy, which reveals the growth of Zn (002) plane. Additionally, the reduced production of H2 during Zn plating/stripping is detected by the in-situ differential electrochemical mass spectrometry (DEMS), which shows the resistance of Zn (002) to hydrogen evolution reaction. The mechanism of dynamic regulation for zinc ion concentration is demonstrated by the in-situ optical microscopy. The hydrated zinc ion can be further plated more rapidly to the uneven location than the case in other regions, which is resulted from the dynamic regulation for zinc ion concentration. Therefore, the uniform Zn plating is formed. A cycling life of 1100 h is exhibited in the Zn||Zn symmetric cell at 1.6 mA cm−2 with the capacity of 1.6 mAh cm−2. The Zn||Cu battery exhibits a cycling life of 200 cycles at 4 mA cm−2 with a capacity of 4 mAh cm−2 and the average Coulombic efficiency is larger than 99 %. The Zn||VO2 battery with HCQ modified electrolyte can operate for 1500 cycles at 4 A g−1 with a capacity retention of 90 %. This strategy in the present work is wished to advance the development of zinc-ion batteries for practical application.

3D Porous Fibers with Spatial Traps and Excellent Zn2+ Transport Kinetics Enable Stable Zn‐Based Aqueous Battery

AbstractAdverse side reactions and uncontrolled Zn dendrites growth are the dominant factors that have restricted the application of Zn ion batteries. Herein, a 3D self‐supporting porous carbon fibers (denoted as PCFs) host is developed with “trap” effect to adjust the Zn deposition. The unique open structural design of N‐doped carbon can act as the zincophilic sites to induce uniform deposition and inhibit adverse side reactions. More importantly, the porous hollow PCFs host with “trap” effect can induce Zn deposition in the fiber by adjusting the local electric field and current density, thereby increasing the specific energy density of the battery and inhibiting dendrite growth. In addition, the 3D open frameworks can regulate Zn2+ flux to enable outstanding cycling performance at ultra‐high current densities. As expected, the PCFs framework guarantees the uniform Zn plating and stripping with an outstanding stability over 6000 cycles at the current density of 40 mA cm−2. And the Zn@PCFs||MnO2 full battery shows an excellent lifespan over 1300 cycles at 2000 mA g−1.

Regulating Desolvation Activation Energy and Zn Deposition via a CTAB-Intercalated Mg-Al-Layered Double-Hydroxide Protective Layer for Durable Zn Metal Anodes.

While aqueous Zn-ion batteries (AZIBs) are widely considered as a promising energy storage system due to their merits of low cost, high specific capacity, and safety, the practical implementation has been hindered by the Zn dendrite growth and undesirable parasitic reactions. To address these issues, a unique hydrophobic-ion-conducting cetyltrimethylammonium bromide-intercalated Mg-Al-layered double-hydroxide protective layer was constructed on the Zn anode (OMALDH-Zn) to modulate the nucleation behavior and desolvation process. The hydrophobic cetyl group long chain can inhibit the hydrogen evolution reaction and Zn corrosion by repelling water molecules from the anode surface and reducing the desolvation activation energy. Meanwhile, the Mg-Al LDH with abundant zincophilic active sites can modulate the Zn2+ ion flux, enabling the dendrite-free Zn deposition. Benefiting from this interfacial synergy, a long cycle life (>2300 h) with low and stable overpotential (<18 mV at 1 mA cm-2) and excellent Coulombic efficiency (99.4%) for symmetrical and asymmetrical batteries were achieved. More impressively, excellent rate performance and long cyclic stability have been realized by OMALDH-Zn//MnO2 batteries in both coin-type and pouch-type devices. This low-cost, simple, and high-efficiency coordinated modulation method provides a reliable strategy for the practical application of AZIBs.

Enhancing the Cycle Life of Zinc–Iodine Batteries in Ionic Liquid‐Based Electrolytes

AbstractAqueous zinc–iodine (Zn−I2) batteries are gaining significant attention due to their low‐cost, high safety and high theoretical capacity. Nevertheless, their long cycle and durability have been hampered due to the use of aqueous media that, over time, lead to Zn dendrite formation, hydrogen evolution reaction, and polyiodide dissolution. Xiao et al. recently reported the addition of an imidazolium‐based ionic liquid (IL) to an aqueous electrolyte and found that the IL plays a key role in modifying the solvation of Zn2+ ions in the bulk electrolyte and the inner Helmholtz plane, repelling H2O molecules away from the Zn anode surface. UV/Vis and NMR spectroscopy also indicates a strong interaction between imidazolium cation [EMIM]+ and I3−, thereby reducing polyiodide shuttling and enhancing the cycle life of the battery. Overall, a capacity decay rate of only 0.01 % per cycle after over 18,000 cycles at 4 A g−1, is observed, making the use of IL additives in aqueous electrolytes highly promising candidates for Zn−I2 batteries.

Enhancing the Cycle Life of Zinc-Iodine Batteries in Ionic Liquid-Based Electrolytes.

Aqueous zinc-iodine (Zn-I2) batteries are gaining significant attention due to their low-cost, high safety and high theoretical capacity. Nevertheless, their long cycle and durability have been hampered due to the use of aqueous media that, over time, lead to Zn dendrite formation, hydrogen evolution reaction, and polyiodide dissolution. Xiao et al. recently reported the addition of an imidazolium-based ionic liquid (IL) to an aqueous electrolyte and found that the IL plays a key role in modifying the solvation of Zn2+ ions in the bulk electrolyte and the inner Helmholtz plane,repelling H2O molecules away from the Zn anode surface. UV/Vis and NMR spectroscopy also indicates a strong interaction between imidazolium cation [EMIM]+ and I3 -, thereby reducing polyiodide shuttling and enhancing the cycle life of the battery. Overall, a capacity decay rate of only 0.01 % per cycle after over 18,000 cycles at 4 A g-1, is observed, making the use of IL additives in aqueous electrolytes highly promising candidates for Zn-I2 batteries.

Regulating interfacial chemistry with biobased multifunctional cellulose levulinate ester for highly reversible zinc ion batteries

The unstable Zn interface, stemming from dendritic and parasitic side reactions, has posed significant challenges to the large-scale implementation of aqueous zinc ion batteries (ZIBs). Herein, a biobased multifunctional cellulose levulinate ester additive, featured by an acetyl propyl ketone moiety, was proposed to regulate the Zn anode/electrolyte interface chemistry. The well-designed cellulose levulinate ester exhibits strong adsorption capacity, fascinating in-situ protective layer, and exposed both hydrogen-bonding acceptor and donor due to the keto-enol tautomerism. The in-situ constructed organic-inorganic bilayer solid-electrolyte interphase enriched with ZnCO3-ZnF2-ZnS component effectively inhibits Zn dendrites, alleviates corrosion, and improves cycle stability. Consequently, the Zn(OTf)2/CLE electrolyte demonstrates highly reversible plating/stripping capability, enabling cycling for more than 2800 h in the shelving-recovery test, affirming their adaptability for long-term aqueous ZIBs. As a conceptual verification, the assembled Zn//MnO2 cells display exceptional cycle stability with a high capacity retention of 78.6 % after 3000 cycles. The in-situ construction of a protective layer on the Zn anode using a biobased multifunctional cellulose levulinate ester additive offers an effective strategy for achieving high-performance Zn metal anodes in aqueous ZIBs.

Easy-to-Lay Poly-N Heterocyclic Additives Enable Long-Term Stabilization of Zinc-Ion Capacitor Anodes under Deep Plating/Stripping.

Addition of organic compounds containing O/N heteroatoms to aqueous electrolytes such as ZnSO4 (ZS) solutions is one of the effective strategies to inhibit Zn anode dendrites and side reactions. However, addressing the stability of Zn plating/stripping at high current densities and areal capacities by this method is still a challenge, especially in capacitors known for high power and long life. Herein, an organic heterocyclic compound of 1, 4, 7, 10-tetraazacyclododecane (TC) containing four symmetrically distributed N atoms is employed as ZS additive, expanding the life of Zn anodes from ≈30h to 1000 and 240h at deep plating/stripping conditions of 10 and 20mAcm-2/mAhcm-2, respectively; the cumulative capacity is as high as 5.0Ahcm-2 with 99% Coulombic efficiency, far exceeding reported additives. TC with higher binding energies than H2O for Zn species tends to adsorb to Zn (002) in a lying manner and participate in the solvation shell of Zn2+, thus avoiding Zn dendrites and side-reaction damage, especially at high current densities. The TC-endowed Zn anode's stability under such extreme conditions is verified in Zn-ion capacitors (i.e., >94.6% capacity retention after 28000 cycles), providing new insights into the development of high-power Zn-based energy storage devices.

Improving Aqueous Zinc Ion Batteries with Alkali Metal Ions.

Aqueous zinc (Zn) ion batteries have received broad attention recently. However, their practical application is limited by severe Zn dendrite growth and the hydrogen evolution reaction. In this study, three alkali metal ions (Li+, Na+, and K+) are added in ZnSO4 electrolytes, which are subjected to electrochemical measurements and molecular dynamics simulations. The studies show that since K+ has the highest mobility and self-diffusion coefficient among the four ions (Li+, Na+, K+, and Zn2+), it enables K+ to preferentially approach a zinc dendrite at an earlier time, driven by a negative electric field during a cathodic process. The electric double layer, with K+ around the negatively charged Zn dendrite, inhibits dendrite growth and mitigates the hydrogen evolution reaction on the Zn anode. Under this kinetic effect, the Zn-Zn symmetric cell with K+ exhibits a long cycling stability of 1000 h at 1 mA·cm-2 of 1 mAh·cm-2 and 190 h at 30 mA·cm-2 of 2 mAh·cm-2. Such a kinetic effect is also observed with additives Na+ and Li+, though less profound than that of K+.

Enhancing Secondary Alkaline Battery Performance: Synthesis and Electrochemical Characterization of Zn Anodes, Based on ZnO@C Core‐Shell Nanoparticles

AbstractWhile alkaline Zn batteries, like traditional rechargeable aqueous batteries, boast an advantage in terms of energy density, their progress has been hampered by concerns related to the anode. These concerns include issues like Zn dendrites, self‐corrosion, passivation, shape change, and the hydrogen evolution reaction (HER). To tackle these challenges, we have introduced a nanostructuring approach for the anode, employing carbon‐coated ZnO nanoparticles (ZnO@C) as the active material. In this study, we synthesized ZnO@C nanoparticles in an environmentally sustainable and scalable manner to address passivation and dissolution issues jointly. Nanoscale ZnO particles effectively prevent passivation, while carbon shell slows down the dissolution of zincate. The Zn anode exhibits a significant performance boost when compared to Zn foil and bare ZnO nanoparticles, even when subjected to demanding conditions (without the use of ZnO‐saturated electrolyte). This rechargeable Zn anode marks a significant step toward the realization of practical, high‐energy rechargeable aqueous batteries, such as Zn‐air batteries.

A Protective Layer of UIO-66/Reduced Graphene Oxide to Stabilize Zinc-Metal Anodes toward High-Performance Aqueous Zinc-Ion Batteries.

Rechargeable aqueous Zn-ion batteries with a Zn anode hold great promise as promising candidates for advanced energy storage systems. The construction of protective layer coatings on Zn anode is an effective way to suppress the growth of Zn dendrites and water-induced side reactions. Herein, we reported a series of UIO-66 materials with different concentrations of reduced graphene oxide (rG) coated onto the surface of Zn foil (Zn@UIO-66/rGx; x = 0.05, 0.1, and 0.2). Benefiting from the synergistic effect of UIO-66 and rG, symmetric cells with Zn@UIO-66/rGx (x = 0.1) electrodes exhibit excellent reversibility (e.g., long cycling life over 1100 h at 1 mA cm-2/1 mAh cm-2) and superior rate capability (e.g., over 1100 and 400 h at 5 mA cm-2/2.5 mAh cm-2 and 10 mA cm-2/5 mAh cm-2, respectively). When the Zn@UIO-66/rG0.1 anode was paired with the NaV3O8·1.5H2O (NVO) cathode, the Zn@UIO-66/rG0.1||NVO cell also delivered a high reversible capacity of 189.9 mAh g-1 with an initial capacity retention of 61.3% after 500 cycles at 1 A g-1, compared to the bare Zn||NVO cell with only 92 cycles.

Imide-pillared covalent organic framework protective films as stable zinc ion-conducting interphases for dendrite-free Zn metal anodes

The notorious growth of zinc dendrite and the water-induced corrosion of zinc metal anodes (ZMAs) restrict the practical development of aqueous zinc ion batteries (AZIBs). In this work, a zinc metallized, imide-pillared covalent organic framework (ZPC) protective film has been engineered as a stable Zn2+ ion-conducting interphase to modulate interfacial kinetics and suppress side reactions for ZMAs. Compared to bare Zn, ZPC@Zn exhibits a higher Zn2+ ionic conductivity, a larger Zn2+ transference number, a lower electronic conductivity, a smaller desolvation activation energy and correspondingly a significant suppression of corrosion, hydrogen evolution and Zn dendrites. Impressively, the ZPC@Zn||ZPC@Zn symmetric cell obtains a cycling lifespan over 3000 h under 5 mA cm−2 for 1 mA h cm−2. The ZPC@Zn||NH4V4O10 coin-type full battery delivers a specific capacity of 195.8 mA h g−1 with a retention rate of 78.5% at 2 A g−1 after 1100 cycles, and the ZPC@Zn||NH4V4O10 pouch full cell shows a retention of 70.1% in reversible capacity at 3 A g−1 after 1100 cycles. The present incorporation of imide-linked covalent organic frameworks in the surface modification of ZMAs will offer fresh perspectives in the search for ideal protective films for the practicality of AZIBs.