Dynamic Biomolecular "Mask" Stabilizes Zn Anode

Dynamic Covalent Bonds Regulate Zinc Plating/Stripping Behaviors for High-Performance Zinc Ion Batteries

Artificial interfaces provide a comprehensive approach to controlling zinc dendrite and surface corrosion in zinc-based aqueous batteries (ZABs). However, due to consistent volume changes during zinc plating/stripping, traditional interfacial layers cannot consistently adapt to the dendrite surface, resulting in uncontrolled dendrite growth and hydrogen evolution. Herein, dynamic covalent bonds exhibit the Janus effect towards zinc deposition at different current densities, presenting a holistic strategy for stabilizing zinc anode. The PBSC intelligent artificial interface consisting of dynamic B-O covalent bonds is developed on zinc anode to mitigate hydrogen evolution and restrict dendrite expansion. Owing to the reversible dynamic bonds, PBSC exhibits shape self-adaptive characteristics at low current rates, which rearranges the network to accommodate volume changes during zinc plating/stripping, resisting hydrogen evolution. Moreover, the rapid association of B-O dynamic bonds enhances mechanical strength at dendrite tips, presenting a shear-thickening effect and suppressing further dendrite growth at high current rates. Therefore, the assembled symmetrical battery with PBSC maintains a stable cycle of 4500 hours without significant performance degradation and the PBSC@Zn||V2O5 pouch cell demonstrates a specific capacity exceeding 170 mAh g-1. Overall, the intelligent interface with dynamic covalent bonds provides innovative approaches for zinc anode interfacial engineering and enhances cycling performance.

Co-Regulating Solvation Structure and Hydrogen Bond Network via Bio-Inspired Additive for Highly Reversible Zinc Anode

The feasibility of aqueous zinc-ion batteries for large-scale energy storage is hindered by the inherent challenges of Zn anode. Drawing inspiration from cellular mechanisms governing metal ion and nutrient transport, erythritol is introduced, a zincophilic additive, into the ZnSO4 electrolyte. This innovation stabilizes the Zn anode via chelation interactions between polysaccharides and Zn2+. Experimental tests in conjunction with theoretical calculation results verified that the erythritol additive can simultaneously regulate the solvation structure of hydrated Zn2+ and reconstruct the hydrogen bond network within the solution environment. Additionally, erythritol molecules preferentially adsorb onto the Zn anode, forming a dynamic protective layer. These modifications significantly mitigate undesirable side reactions, thus enhancing the Zn2+ transport and deposition behavior. Consequently, there is a notable increase in cumulative capacity, reaching 6000 mA h cm⁻2 at a current density of 5 mA cm-2. Specifically, a high average coulombic efficiency of 99.72% and long cycling stability of >500 cycles are obtained at 2 mA cm-2 and 1 mA h cm-2. Furthermore, full batteries comprised of MnO2 cathode and Zn anode in an erythritol-containing electrolyte deliver superior capacity retention. This work provides a strategy to promote the performance of Zn anodes toward practical applications.

Restraining the shuttle effect of polyiodides and modulating the deposition of zinc ions to enhance the cycle lifespan of aqueous Zn-I2 batteries

The boom of aqueous Zn-based energy storage devices, such as zinc-iodine (Zn-I2) batteries, is quite suitable for safe and sustainable energy storage technologies. However, in rechargeable aqueous Zn-I2 batteries, the shuttle phenomenon of polyiodide ions usually leads to irreversible capacity loss resulting from both the iodine cathode and the zinc anode, and thus impinges on the cycle lifespan of the battery. Herein, a nontoxic, biocompatible, and economical polymer of polyvinyl alcohol (PVA) is exploited as an electrolyte additive. Based on comprehensive analysis and computational results, it is evident that the PVA additive, owing to its specific interaction with polyiodide ions and lower binding energy, can effectively suppress the migration of polyiodide ions towards the zinc anode surface, thereby mitigating adverse reactions between polyiodide ions and zinc. Simultaneously, the hydrogen bond network of water molecules is disrupted due to the abundant hydroxyl groups within the PVA additive, leading to a decrease in water activity and mitigating zinc corrosion. Further, because of the preferential adsorption of PVA on the zinc anode surface, the deposition environment for zinc ions is adjusted and its nucleation overpotential increases, which is favorable for the dense and uniform deposition of zinc ions, thus ensuring the improvement of the performance of the Zn-I2 battery. This investigation has inspired the development of a user-friendly and high-performance Zn-I2 battery.

Amphipathic Phenylalanine-Induced Nucleophilic-Hydrophobic Interface Toward Highly Reversible Zn Anode

Aqueous Zn2+-ion batteries (AZIBs), recognized for their high security, reliability, and cost efficiency, have garnered considerable attention. However, the prevalent issues of dendrite growth and parasitic reactions at the Zn electrode interface significantly impede their practical application. In this study, we introduced a ubiquitous biomolecule of phenylalanine (Phe) into the electrolyte as a multifunctional additive to improve the reversibility of the Zn anode. Leveraging its exceptional nucleophilic characteristics, Phe molecules tend to coordinate with Zn2+ ions for optimizing the solvation environment. Simultaneously, the distinctive lipophilicity of aromatic amino acids empowers Phe with a higher adsorption energy, enabling the construction of a multifunctional protective interphase. The hydrophobic benzene ring ligands act as cleaners for repelling H2O molecules, while the hydrophilic hydroxyl and carboxyl groups attract Zn2+ ions for homogenizing Zn2+ flux. Moreover, the preferential reduction of Phe molecules prior to H2O facilitates the in situ formation of an organic-inorganic hybrid solid electrolyte interphase, enhancing the interfacial stability of the Zn anode. Consequently, Zn||Zn cells display improved reversibility, achieving an extended cycle life of 5250 h. Additionally, Zn||LMO full cells exhibit enhanced cyclability of retaining 77.3% capacity after 300 cycles, demonstrating substantial potential in advancing the commercialization of AZIBs.

Self-Adaptive Liquid Film: Dynamic Realization of Dendrite-Free Zn Deposition Toward Ultralong-Life Aqueous Zn Battery

The poor reversibility and stability of Zn metal anode (ZMA) caused by uncontrolled Zn deposition behaviors and serious side reactions severely impeded the practical application of aqueous Zn metal battery. Herein, a liquid-dynamic and self-adaptive protective layer (LSPL) was constructed on the ZMA surface for inhibiting dendrites and by-products formation. Interestingly, the outer LSPL consists of liquid perfluoropolyether (PFPE), which can dynamically adapt volume change during repeat cycling and inhibit side reactions. Moreover, it can also decrease the de-solvation energy barrier of Zn2+ by strong interaction between C-F bond and foreign Zn2+ , improving Zn2+ transport kinetics. For the LSPL inner region, in-situ formed ZnF2 through the spontaneous chemical reaction between metallic Zn and part PFPE can establish an unimpeded Zn2+ migration pathway for accelerating ion transfer, thereby restricting Zn dendrites formation. Consequently, the LSPL-modified ZMA enables reversible Zn deposition/dissolution up to 2000 h at 1 mA cm-2 and high coulombic efficiency of 99.8% at 4 mA cm-2 . Meanwhile, LSPL@Zn||NH4 V4 O10 full cells deliver an ultralong cycling lifespan of 100 00 cycles with 0.0056% per cycle decay rate at 10 A g-1 . This self-adaptive layer provides a new strategy to improve the interface stability for next-generation aqueous Zn battery.

The synthesis and application of crystalline-amorphous hybrid materials

Crystalline-amorphous hybrid materials (CA-HMs) possess the merits of both pure crystalline and amorphous phases. Abundant dangling bonds, unsaturated coordination atoms, and isotropic structural features in the amorphous phase, as well as relatively high electronic conductivity and thermodynamic structural stability of the crystalline phase simultaneously take effect in CA-HMs. Furthermore, the atomic and bandgap mismatch at the CA-HM interface can introduce more defects as extra active sites, reservoirs for promoted catalytic and electrochemical performance, and induce built-in electric field for facile charge carrier transport. Motivated by these intriguing features, herein, we provide a comprehensive overview of CA-HMs on various aspects-from synthetic methods to multiple applications. Typical characteristics of CA-HMs are discussed at the beginning, followed by representative synthetic strategies of CA-HMs, including hydrothermal/solvothermal methods, deposition techniques, thermal adjustment, and templating methods. Diverse applications of CA-HMs, such as electrocatalysis, batteries, supercapacitors, mechanics, optoelectronics, and thermoelectrics along with underlying structure-property mechanisms are carefully elucidated. Finally, challenges and perspectives of CA-HMs are proposed with an aim to provide insights into the future development of CA-HMs.

Interface regulation of the Zn anode by using a low concentration electrolyte additive for aqueous Zn batteries

The Zn metal anode in aqueous Zn batteries faces a number of challenges including instable deposition and corrosion issues. Here, we present an interface environment regulation for a Zn electrode with a low concentration electrolyte additive of 0.1 m 3-aminobenzenesulfonic acid (ASA). ASA prefers to adsorb on the Zn surface over water and creates an ASA-rich interface. It further enters the Zn2+ solvation sheath locally, which shifts the lowest unoccupied molecular orbital from solvated water to ASA. The hydrogen evolution reaction from solvated water reduction is inhibited, and the reduction of solvated ASA generates a stable solid-electrolyte interphase composed of the ion conductor ZnS covered by organic-inorganic mixed components. With the resulting homogenized Zn deposition, continuous Zn stripping in symmetric cells reaches 99.7% depth of discharge (DOD) at a current density of 2 mA cm-2, whereas cell short-circuit takes place at 11.4% DOD in the ASA free ZnSO4 electrolyte. The repeated stripping/plating also realizes 1100 h cycle life at 2 mA cm-2, and a 99.54% stabilized coulombic efficiency is obtained for 500 cycles at 10 mA cm-2.

Electrolyte Modulation of Biological Chelation Additives toward a Dendrite-Free Zn Metal Anode

Aqueous zinc-ion batteries are considered promising energy storage devices due to their superior electrochemical performance. Nevertheless, the uncontrolled dendrites and parasitic side reactions adversely affect the stability and durability of the Zn anode. To cope with these issues, inspired by the chelation behavior between metal ions and amino acids in the biological system, glutamic acid and aspartic acid are selected as electrolyte additives to stabilize the Zn anode. Experimental characterizations in conjunction with theoretical calculation results indicate that these additives can simultaneously modify the solvation structure of hydrated Zn2+ and preferentially adsorb onto the Zn anode, thereby restricting the occurrence of interfacial side reactions and enhancing the performance of the Zn anode. Benefiting from these synergistic effects, the as-assembled Zn-based batteries containing additive electrolytes achieved admirable electrochemical performance. From the viewpoint of electrolyte regulation, this work provides a bright direction toward the development of aqueous batteries.

A biocompatible electrolyte enables highly reversible Zn anode for zinc ion battery

Progress towards the integration of technology into living organisms requires power devices that are biocompatible and mechanically flexible. Aqueous zinc ion batteries that use hydrogel biomaterials as electrolytes have emerged as a potential solution that operates within biological constraints; however, most of these batteries feature inferior electrochemical properties. Here, we propose a biocompatible hydrogel electrolyte by utilising hyaluronic acid, which contains ample hydrophilic functional groups. The gel-based electrolyte offers excellent anti-corrosion ability for zinc anodes and regulates zinc nucleation/growth. Also, the gel electrolyte provides high battery performance, including a 99.71% Coulombic efficiency, over 5500 hours of long-term stability, improved cycle life of 250 hours under a high zinc utilization rate of 80%, and high biocompatibility. Importantly, the Zn//LiMn2O4 pouch cell exhibits 82% capacity retention after 1000 cycles at 3 C. This work presents a promising gel chemistry that controls zinc behaviour, offering great potential in biocompatible energy-related applications and beyond.

In Situ Buildup of Zinc Anode Protection Films with Natural Protein Additives for High-Performance Zinc Battery Cycling

The uncontrolled growth of dendrites and serious side reactions, such as hydrogen evolution and corrosion, significantly hinder the industrial application and development of aqueous zinc-ion batteries (ZIBs). This article presents ovalbumin (OVA) as a multifunctional electrolyte additive for aqueous ZIBs. Experimental characterizations and theoretical calculations reveal that the OVA additive can replace the solvated sheath of recombinant hydrated Zn²⁺ through the coordination water, preferentially adsorb on the surface of the Zn anode, and construct a high-quality self-healing protective film. Notably, the OVA-based protective film with strong Zn²⁺ affinity will promote uniform Zn deposition and inhibit side reactions. As a result, Zn||Zn symmetrical batteries in ZnSO₄ electrolytes containing OVA achieve a cycle life exceeding 2200 h. Zn||Cu batteries and Zn||MnO₂ (2 A g^-1) full batteries show excellent cycling stability for 2500 cycles, demonstrating promising application prospects. This study provides insights into utilizing natural protein molecules to modulate the kinetics of Zn²⁺ diffusion and enhance the stability of the anode interface.

Electrolyte Regulation of Bio-Inspired Zincophilic Additive toward High-Performance Dendrite-Free Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries hold attractive potential for large-scale energy storage devices owing to their prominent electrochemical performance and high security. Nevertheless, the applications of aqueous electrolytes have generated various challenges, including uncontrolled dendrite growth and parasitic reactions, thereby deteriorating the Zn anode's stability. Herein, inspired by the superior affinity between Zn²⁺ and amino acid chains in the zinc finger protein, a cost-effective and green glycine additive is incorporated into aqueous electrolytes to stabilize the Zn anode. As confirmed by experimental characterizations and theoretical calculations, the glycine additives can not only reorganize the solvation sheaths of hydrated Zn²⁺ via partial substitution of coordinated H₂ O but also preferentially adsorb onto the Zn anode, thereby significantly restraining dendrite growth and interfacial side reactions. Accordingly, the Zn anode could realize a long lifespan of over 2000 h and enhanced reversibility (98.8%) in the glycine-containing electrolyte. Furthermore, the assembled Zn||α-MnO₂ full cells with glycine-modified electrolyte also delivers substantial capacity retention (82.3% after 1000 cycles at 2 A g^-1 ), showing promising application prospects. This innovative bio-inspired design concept would inject new vitality into the development of aqueous electrolytes.