Improved Strategies for Separators in Zinc-Ion Batteries

Recent advances in cellulose-based separators for zinc ion batteries: A review

Aqueous zinc ion batteries (AZIBs) have attracted increasing attention because of their high energy density, excellent safety features, and environmentally friendly properties. The separator plays a crucial role in the battery, greatly influencing its performance and stability. Therefore, the separator for AZIBs has attracted increasing interest in recent years. Glass fiber (GF) is the predominant separator material, and exhibits favorable hydrophilicity and remarkable ionic conductivity. Nevertheless, its internal inhomogeneous pore structure makes it difficult to achieve uniform deposition of zinc ions, while the GF separator is easy to pierce due to its inadequate mechanical properties. In response to these issues, cellulose materials have garnered significant interest owing to their exceptional hydrophilicity, cost-effectiveness, and widespread availability. This review summarizes the potential of cellulose separators to substitute GF separators for AZIBs because of their high porosity, ion mobility number, electrolyte wetting rate, and liquid absorption rate. Different methods for preparing cellulose separators for AZIBs and various strategies to enhance their performance are summarized. The future outlook of cellulose-based separators for ZIBs is also prospected.

Buried interface engineering towards stable zinc anodes for high-performance aqueous zinc-ion batteries

The dendrite and corrosion issues still remain for zinc anodes. Interface modification of anodes has been widely used for stabilizing zinc anodes. However, it is still quite challenging for such modification to simultaneously suppress zinc dendrites and corrosion issues. Herein, we propose a new strategy of buried interface engineering to effectively stabilize Zn anodes, in which a zincophilic Sn layer is buried by a corrosion-resistant ZnS layer (SZS). The buried Sn layer has a strong adsorption energy towards Zn atoms, which accelerates the nucleation of Zn atoms and induces smooth deposition. Meanwhile, the outer ZnS layer protects the newly deposited zinc layer from the corrosion by the electrolyte. As a result, the SZS@Zn symmetric cell demonstrates stable cycling for over 280 h compared to Bare Zn (41 h) at a high current of 10 mA cm-2 and a high areal capacity of 10 mAh cm-2. Besides, SZS@Zn//MnO2 full cells also achieve enhanced long-term cycling stability of 63.6% for 1000 cycles at a high rate of 10 C, compared to Bare Zn (47.2%). This work provides a new strategy of buried interface for the rational design of highly stable metal anodes for other metal batteries.

Eco-friendly and strong lignin-containing microfibrillated cellulose films for high-performance separators of aqueous zinc batteries

Aqueous zinc-ion batteries have gained significant interest, offering several distinct advantages over conventional lithium-ion batteries owing to their compelling low cost, enhanced battery safety, and excellent environmental friendliness. Nevertheless, the unfortunate growth of zinc dendrites during cycling leads to poor electrochemical performance of zinc batteries, primarily attributed to the diminished wet mechanical properties and limited electrolyte uptake of existing commercial separators. Herein, a bio-based separator was developed from sustainable resources using natural polymers derived from wood pulp to replace fossil-based polyolefin separators. The inherent hydrophilicity and swelling ability of cellulose fibers provide separators with superior electrolyte wettability and uptake. Notably, the structural reinforcement provided by lignin, especially after hot pressing, enhances the separator's wet mechanical integrity and performance during battery cycling. These improvements contribute to the separator's more stable electrochemical performance and improved ion transport properties. Separators composed of lignin-rich microfibrillated cellulose fibers showed superior dimensional stability under heat compared to Celgard, ensuring higher thermal safety and enhanced performance of aqueous zinc-ion batteries. Our results reveal the great potential of lignin-rich cellulose-based separators for future zinc-ion batteries.

Recent Advances in Current Collectors for Aqueous Zinc-ion Batteries

Aqueous zinc-ion batteries (AZIBs) are promising options for large-scale electrical energy storage because of their safety, affordability, and environmental friendliness. As an indispensable component of AZIBs, a current collector plays a crucial role in supporting electrode materials and collecting the accumulated electrical energy. Recently, some progress has been made in the study of current collectors for AZIBs; however, only few comprehensive reviews on this topic are available. In this review, the systematic summary and discussion of research progress on current collectors for AZIBs is presented. Furthermore, the main challenges and key prospects for the future development of current collectors for AZIBs are discussed.

Modulating Ion Behavior by Functional Nanodiamond Modified Separator for High-Rate Durable Aqueous Zinc-Ion Battery

Aqueous zinc-ion batteries (AZIBs) have garnered widespread attention due to their promising development and application prospects. However, progress of AZIBs has been hindered by zinc (Zn) dendrites and side reactions at the electrode-electrolyte interface (EEI). In particular, the large and uneven pores of commercial glass fiber (GF) separators lead to nonuniform Zn2+ transport, which causes side reactions. In this study, we employed nanodiamonds (NDs) to regulate the separator pore structure and utilized its surface oxygen-containing functional groups to control the Zn2+ transport properties. Due to their excellent chemical inertness, superhardness, ultrahigh thermal conductivity, and abundant surface functional groups, NDs modified GF separators for dendrite-free and high-performance AZIBs. Experimental outcomes demonstrate that Zn||Zn symmetric cells using NDs-GF separators exhibit regular charge-discharge profiles, minimal fluctuations, and an ultralong cycling lifespan of nearly 1800 h under a current density of 5 mA cm-2 with a capacity density of 1 mAh cm-2 and 240 h under a high current density of 10 mA cm-2 with a capacity density of 10 mAh cm-2. The Zn||MnO2 full cells using NDs-GF separators showcase a high retention after 1000 cycles at 1 A g-1. This research proposes a modification method for developing advanced separators in AZIBs technology.

Organic Electrolyte Additives for Aqueous Zinc Ion Batteries: Progress and Outlook

Aqueous zinc ion batteries (AZIBs) are considered one of the most prospective new-generation electrochemical energy storage devices with the advantages of high specific capacity, good safety, and high economic efficiency. Nevertheless, the enduring problems of low Coulombic efficiency (CE) and inadequate cycling stability of zinc anodes, originating from dendrites, hydrogen precipitation and passivation, are closely tied to their thermodynamic instability in aqueous electrolytes, which significantly shortens the cycle life of the battery. Electrolyte additives can solve the above difficulties and are important for the advancement of affordable and reliable AZIBs. Organic electrolyte additives have attracted widespread attention due to their unique properties, however, there is a lack of systematic discussion on the performance and mechanism of action of organic electrolyte additives. In this review, a comprehensive overview of the application of organic electrolyte additives in AZIBs is presented. The role of organic electrolyte additives in stabilizing zinc anodes is described and evaluated. Finally, further potential directions and prospects for improving and directing organic electrolyte additives for AZIBs are presented.

High-Capacity Zinc Anode Enabled by a Recyclable Biomass Bamboo Membrane Separator

Aqueous zinc ion batteries have gained attention as viable energy storage systems, yet the occurrence of detrimental side reactions and Zn dendrite formation undermines the efficiency of Zn anodes. Controlling water activity have proven to be an effective strategy in mitigating these challenges. However, strategies such as electrolyte design and electrode protection layer show weakness to varying degrees. Here, a new oxygen-functionalized biomass bamboo membrane separator (denoted as BM) is proposed to restrain the activity of water molecules. This BM separator features a unique, multi-tiered 2D interlayer that facilitates rapid ion diffusion. Additionally, the oxygen functional groups of the BM separator can form hydrogen bonds with water molecules, effectively transforming water molecules from a free state to a bound state. Consequently, the Zn/Zn asymmetric coin cell using BM can work at the ultrahigh rate and capacity of 30 mA cm-2 and 30 mAh cm-2 for more than 80 h while its counterparts using glass fiber can barely work. Moreover, full cells using BM separator exhibited a capacity retention of 89.7% after 1000 cycles at 10 A g-1. This study reveals the important influence of water-limited activity on Zn anode protection and provides an avenue for the design of novel separator.

Ion-Sieving Separator Functionalized by Natural Mineral Coating toward Ultrastable Zn Metal Anodes

Aqueous zinc-ion batteries (AZIBs) exhibit promising prospects in becoming large-scale energy storage systems due to environmental friendliness, high security, and low cost. However, the growth of Zn dendrites and side reactions remain heady obstacles for the practical application of AZIBs. To solve these challenges, a functionalized Janus separator is successfully constructed by coating halloysite nanotubes (HNTs) on glass fiber (GF). Impressively, the different electronegativity on the inner and outer surfaces of HNTs endows the HNT-GF separator with ion-sieving property, leading to a significantly high transference number of Zn2+ (tZn2+ = 0.71). Meanwhile, the HNT-GF separator works as an interfacial ion comb to regular Zn2+ flux and realizes multisite progressive nucleation, bringing decreased nucleation overpotential and uniform Zn2+ deposition. Consequently, the HNT-GF separator enables the Zn anode to display an ultralong plating/stripping life of 3000 h and high rate tolerance with a stable long cycle life even under a density of 50 mA cm-2. Moreover, the Z n ∥ H N T - G F ∥ M n O 2 full cell represents an ultrastable cycling stability with a high capacity retention of 93.4% even after 1000 cycles at a current density of 2 A g-1. This work provides a convenient method for the separator modification of AZIBs.

Critical Effects of Insoluble Additives in Liquid Electrolytes for Metal Batteries

Rechargeable metal batteries have received widespread attention due to their high energy density by using pure metal as the anode. However, there are still many fundamental problems that need to be solved before approaching practical applications. The critical ones are low charge/discharge current due to slow ion transport, short cycle lifetime due to poor anode/cathode stability, and unsatisfied battery safety. To tackle these problems, various strategies have been suggested. Among them, electrolyte additive is one of the most widely used strategies. Most of the additives currently studied are soluble, but their reliability is questionable, and they can easily affect the electrochemical process, causing unwanted battery performance decline. On the contrary, insoluble additives with excellent chemical stability, high mechanical strength, and dimensional tunability have attracted considerable research exploration recently. However, there is no timely review on insoluble additives in metal batteries yet. This review summarizes various functions of insoluble additives: ion transport modulation, metal anode protection, cathode amelioration, as well as battery safety enhancement. Future research directions and challenges for insoluble solid additives are also proposed. It is expected this review will stimulate inspiration and arouse extensive studies on further improvement in the overall performance of metal batteries.

Molecular Dynamics Simulation Investigation of Freezing Point Depression in NaClO4 Electrolyte Solution by CaCl2

The development of inorganic antifreeze electrolytes is of paramount importance for the application of sodium-ion batteries under low-temperature conditions. However, there is little reported about their molecular mechanism for lowering the freezing point of electrolytes. Therefore, this study explores the mechanism by which CaCl2 lowers the freezing point of the NaClO4 electrolyte. Hexagonal ice (ice Ih) was used as the ice seed, and CaCl2 was selected as the antifreeze agent. The coexistence system of ice and solution was constructed to simulate the freezing process. It was found that there is ion rejection at the ice layer, with ions predominantly distributed in the solution. Over time, ions form an ion adsorption layer at the ice-solution interface. The radial distribution function (RDF) and spatial distribution function (SDF) of Na+, ClO4-, Ca2+, and Cl- revealed that ions form the first solvation shells with water molecules. The interaction energy between ions and water molecules is greater than that between ice nuclei and water. Therefore, ions are better able to maintain the stability of their solvation shells and inhibit the growth of ice Ih through a mechanism of competition for water molecules. Furthermore, the dissolution free energy of Na+ and Ca2+ in the aqueous phase was studied. The results indicated that Ca2+ has a stronger affinity for water molecules than Na+, making it more competitive in competing for water with ice Ih. Therefore, CaCl2 in NaClO4 solution can reduce the freezing point. This work provides a molecular-level understanding of how CaCl2 reduces the freezing point of NaClO4 solution, which is beneficial for designing strategies for low-temperature electrolytes.

Constructing a 3D Zinc Anode Exposing the Zn(002) Plane for Ultralong Life Zinc-Ion Batteries

The limited lifespan of aqueous Zn-ion batteries (ZIBs) is primarily attributed to the irreversible issues associated with the Zn anode, including dendrite growth, hydrogen evolution, and side reactions. Herein, a 3D Zn anode exposing Zn(002) crystal planes (3D-Zn(002) anode) is first constructed by an electrostripping method in KNO3 solution. Experiments and theoretical calculations indicate that the priority adsorption of KNO3 on Zn(100) and Zn(101) planes decreases the dissolution energy of Zn atoms, thereby exposing more Zn(002) planes. The 3D-Zn(002) anode effectively regulates ion flux to realize the uniform nucleation of Zn2+. Moreover, it can inhibit water-induced formation of side-products and hydrogen evolution reaction. Consequently, the 3D-Zn(002) symmetrical cell exhibits an exceptionally long lifespan surpassing 6000 h at 5.0 mA cm-2 with a capacity of 1.0 mAh cm-2, and enduring 8500 cycles at 30 mA cm-2 with a capacity of 1.0 mAh cm-2. Besides, when NH4V4O10 is used as the cathode, the 3D-Zn(002)//NH4V4O10 full cell shows stable cycling performance with a capacity retention rate of 75.7% after 4000 cycles at 5.0 A g-1. This study proposes a feasible method employing a 3D-Zn(002) anode for enhancing the cycling durability of ZIBs.

Advances of Nanomaterials for High-Efficiency Zn Metal Anodes in Aqueous Zinc-Ion Batteries

Aqueous zinc-ion batteries (AZIBs) have emerged as one of the most promising candidates for next-generation energy storage devices due to their outstanding safety, cost-effectiveness, and environmental friendliness. However, the practical application of zinc metal anodes (ZMAs) faces significant challenges, such as dendrite growth, hydrogen evolution reaction, corrosion, and passivation. Fortunately, the rapid rise of nanomaterials has inspired solutions for addressing these issues associated with ZMAs. Nanomaterials with unique structural features and multifunctionality can be employed to modify ZMAs, effectively enhancing their interfacial stability and cycling reversibility. Herein, an overview of the failure mechanisms of ZMAs is presented, and the latest research progress of nanomaterials in protecting ZMAs is comprehensively summarized, including electrode structures, interfacial layers, electrolytes, and separators. Finally, a brief summary and optimistic perspective are given on the development of nanomaterials for ZMAs. This review provides a valuable reference for the rational design of efficient ZMAs and the promotion of large-scale application of AZIBs.

Industrial Waste Derived Separators for Zn-Ion Batteries Achieve Homogeneous Zn(002) Deposition Through Low Chemical Affinity Effects

Designing a cost-effective and multifunctional separator that ensures dendrite-free and stable Zn metal anode remains a significant challenge. Herein, a multifunctional cellulose-based separator is presented consisting of industrial waste-fly ash particles and cellulose nanofiber using a facile solution-coating method. The resulting fly ash-cellulose (FACNF) separators enable a high ion conductivity (5.76 mS cm-1) and low desolvation energy barrier of hydrated Zn2+. These features facilitate fast ion transfer kinetics and inhibit water-induced side reactions. Furthermore, experimental results and theoretical simulations confirm that the presence of fly ash particles in FACNF separators effectively accommodate the preferential deposition of Zn(002) planes, due to the weak chemical affinity between Zn(002) plane and fly ash, to mitigate dendrite formation and growth. Consequently, the utilization of FACNF separators causes an impressive cycling performance in both Zn||Zn symmetric cells (1600 h at 2 mA cm-2/1 mAh cm-2) and Zn||(NH4)2V10O25 (NVO) full cells (4000 cycles with the capacity retention of 92.1% at 5 A g-1). Furthermore, the assembled pouch cells can steadily support digital thermometer over two months without generating gas and volume expansion. This work provides new insights for achieving crystallographic uniformity in Zn anodes and realizing cost-effective and long-lasting aqueous zinc-ion batteries (AZIBs).

Synthesis of Co@CoO/C by micro-tube method and their electrochemical performances

Lithium-ion batteries (LIBs) are promising secondary batteries that are widely used in portable electronic devices, electric vehicles and smart grids. The design and synthesis of high-performance electrode materials play a crucial role in achieving lithium-ion batteries with high energy density, prolonged cycle life, and superior safety. CoO has attracted significant attention as a negative electrode material for lithium-ion batteries due to its high theoretical capacity and abundant resources. However, its limited conductivity and suboptimal cycling performance impede its potential applications. The study proposes a novel micro-tube reaction method for the synthesis of Co@CoO/C, utilizing Kapok fiber as a template with a special hollow structure. The microstructure and composition of the samples were characterized using X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). After conducting electrochemical performance tests, it was discovered that at a current density of 100 mA/g and within the range of 0.01-3.0 V for 50 charge and discharge cycles. Co@CoO/C composite negative electrode exhibits a reversible lithium insertion specific capacity of 499.8 mAh/g and keep a discharge capacity retention rate of 97.6 %. The greatly improved lithium storage and stability performance of Co@CoO/C composite anode is mainly attributed to the synergistic effect between Co@CoO nanoparticles and the kapok carbon microtubule structure.

Chelating Additive Regulating Zn-Ion Solvation Chemistry for Highly Efficient Aqueous Zinc-Metal Battery

Aqueous zinc-metal batteries (AZMBs) usually suffered from poor reversibility and limited lifespan because of serious water induced side-reactions, hydrogen evolution reactions (HER) and rampant zinc (Zn) dendrite growth. Reducing the content of water molecules within Zn-ion solvation sheaths can effectively suppress those inherent defects of AZMBs. In this work, we originally discovered that the two carbonyl groups of N-Acetyl-ϵ-caprolactam (N-ac) chelating ligand can serve as dual solvation sites to coordinate with Zn2+, thereby minimizing water molecules within Zn-ion solvation sheaths, and greatly inhibit water-induced side-reactions and HER. Moreover, the N-ac chelating additive can form a unique physical barrier interface on Zn surface, preventing the harmful contacting with water. In addition, the preferential adsorption of N-ac on Zn (002) facets can promote highly reversible and dendrite-free Zn2+ deposition. As a result, Zn//Cu half-cell within N-ac added electrolyte delivered ultra-high 99.89 % Coulombic efficiency during 8000 cycles. Zn//Zn symmetric cells also demonstrated unprecedented long life of more than 9800 hours (over one year). Aqueous Zn//ZnV6O16 ⋅ 8H2O (Zn//ZVO) full-cell preserved 78 % capacity even after ultra-long 2000 cycles. A more practical pouch-cell was also obtained (90.2 % capacity after 100 cycles). This method offers a promising strategy for accelerating the development of highly efficient AZMBs.

Dendrite-Free Zinc Anodes Enabled by Exploring Polar-Face-Rich 2D ZnO Interfacial Layers for Rechargeable Zn-Ion Batteries

Zinc metal is a promising candidate for anodes in zinc-ion batteries (ZIBs), but its widespread implementation is hindered by dendrite growth in aqueous electrolytes. Dendrites lead to undesirable side reactions, such as hydrogen evolution, passivation, and corrosion, causing reduced capacity during prolonged cycling. In this study, an approach is explored to address this challenge by directly growing 1D zinc oxide (ZnO) nanorods (NRs) and 2D ZnO nanoflakes (NFs) on Zn anodes, forming artificial layers to enhance ZIB performance. The incorporation of ZnO on the anode offers both chemical and thermal stability and leverages its n-type semiconductor nature to facilitate the formation of ohmic contacts. This results in efficient electron transport during Zn ion plating and stripping processes. Consequently, the ZnO NFs-coated Zn anodes demonstrate significantly improved charge storage performance, achieving 348 mAh g-1, as compared to ZnO NRs (250 mAh g-1) and pristine Zn (160 mAh g-1) anodes when evaluated in full cells with V2O5 cathodes. One significant advantage of ZnO NFs lies in their highly polar surfaces, promoting strong interactions with water molecules and rendering them exceptionally hydrophilic. This characteristic enhances the ability of ZnO NFs to desolvate Zn2+ ions, leading to improved charge storage performance.

Recent Advances in Graphene-Based Materials for Zinc-Ion Batteries

Zinc-ion batteries (ZIBs) are a promising alternative for large-scale energy storage due to their advantages of environmental protection, low cost, and intrinsic safety. However, the utilization of their full potential is still hindered by the sluggish electrode reaction kinetics, poor structural stability, severe Zn dendrite growth, and narrow electrochemical stability window of the whole battery. Graphene-based materials with excellent physicochemical properties hold great promise for addressing the above challenges foe ZIBs. In this review, the energy storage mechanisms and challenges faced by ZIBs are first discussed. Key issues and recent progress in design strategies for graphene-based materials in optimizing the electrochemical performance of ZIBs (anode, cathode, electrolyte, separator and current collector) are then discussed. Finally, some potential challenges and future research directions of graphene-based materials in high-performance ZIBs are proposed for practical applications.

Inorganic Oxide-Based "Hydrophobic-Hydrophilic-Hydrophobic" Separators Systems for Long-Life Zinc-Ion Batteries

Hydrogen reduction reaction (HER) and corrosion limit the long-life cycle of zinc-ion batteries. However, hydrophilic separators are unable to prevent direct contact between water and electrodes, and hydrophobic separators have difficulty in transporting electrolytes. In this work, an inorganic oxide-based "hydrophobic-hydrophilic-hydrophobic" self-assembled separator system is proposed. The hydrophobic layer consists of a porous structure, which can isolate a large amount of free water to avoid HER and corrosion reactions, and can transport electrolyte by binding water. The middle hydrophilic layer acts as a storage layer consisting of the GF separator, storing large amounts of electrolyte for proper circulation. By using this structure separator, Zn||Zn symmetric cell achieve 2200 h stable cycle life at 5 mA cm-2 and 1mAh cm-2 and still shows a long life of 1800 h at 10 mA cm-2 and 1mAh cm-2. The assembled Zn||VO2 full cell displays high specific capacity and excellent long-term durability of 60.4% capacity retention after 1000 cycles at 2C. The assembled Zn||VO2 pouch full cell displays high specific capacity of 172.5mAh g-1 after 40 cycles at 0.5C. Changing the inorganic oxide materials, the hydrophobic-hydrophilic-hydrophobic structure of the separators still has excellent performance. This work provides a new idea for the engineering of water-based battery separators.

Recent advances in electrospinning nanofiber materials for aqueous zinc ion batteries

Aqueous zinc ion batteries (AZIBs) are regarded as one of the most promising large-scale energy storage systems because of their considerable energy density and intrinsic safety. Nonetheless, the severe dendrite growth of the Zn anode, the serious degradation of the cathode, and the boundedness of separators restrict the application of AZIBs. Fortunately, electrospinning nanofibers demonstrate huge potential and bright prospects in constructing AZIBs with excellent electrochemical performance due to their controllable nanostructure, high conductivity, and large specific surface area (SSA). In this review, we first briefly introduce the principles and processing of the electrospinning technique and the structure design of electrospun fibers in AZIBs. Then, we summarize the recent advances of electrospinning nanofibers in AZIBs, including the cathodes, anodes, and separators, highlighting the nanofibers' working mechanism and the correlations between electrode structure and performance. Finally, based on insightful understanding, the prospects of electrospun fibers for high-performance AZIBs are also presented.

Recent Research Progress into Zinc Ion Battery Solid-Electrolyte Interfaces

Aqueous zinc ion batteries (ZIBs) are prospective next-generation energy storage device candidates owing to resource abundance, affordability, eco-friendliness, and safety. The solid-electrolyte interface (SEI) produced in a ZIB by electrolyte/electrode interactions significantly impacts battery performance. The SEI is known to promote dendrite growth, determine the electrochemical stability window, passivate zinc-metal-anodic corrosion, and mutate the electrolyte. Accordingly, the SEI is closely related to the overall property of a ZIB device. This review provides an overview of the impact of SEIs on ZIB performance recently and provides an SEI design strategy based on the formation mechanism, type, and characteristics of the SEI. Finally, future investigational directions for SEIs in ZIBs are expected to lead to a deep understanding of the SEI, enhance ZIB performance, and facilitate their extensive implementation.

Construction of Microporous Zincophilic Interface for Stable Zn Anode

Aqueous zinc ion batteries (AZIBs) are promising electrochemical energy storage devices due to their high theoretical specific capacity, low cost, and environmental friendliness. However, uncontrolled dendrite growth poses a serious threat to the reversibility of Zn plating/stripping, which impacts the stability of batteries. Therefore, controlling the disordered dendrite growth remains a considerable challenge in the development of AZIBs. Herein, a ZIF-8-derived ZnO/C/N composite (ZOCC) interface layer was constructed on the surface of the Zn anode. The homogeneous distribution of zincophilic ZnO and the N element in the ZOCC facilitates directional Zn deposition on the (002) crystal plane. Moreover, the conductive skeleton with a microporous structure accelerates Zn²⁺ transport kinetics, resulting in a reduction in polarization. As a result, the stability and electrochemical properties of AZIBs are improved. Specifically, the ZOCC@Zn symmetric cell sustains over 1150 h at 0.5 mA cm^-2 with 0.25 mA h cm^-2, while the ZOCC@Zn half-cell achieves an outstanding Coulombic efficiency of 99.79% over 2000 cycles. This work provides a simple and effective strategy for improving the lifespan of AZIBs.

The Promotion of Research Progress of Zinc Manganate Cathode Materials for Zinc-Ion Batteries by Characterization and Analysis Technology

Zinc-ion batteries (ZIBs) have recently attracted great interest and are regarded as a promising energy storage device due to their low cost, environmental friendliness, and superior safety. However, the development of suitable Zn-ion intercalation cathode materials remains a great challenge, resulting in unsatisfactory ZIBs that cannot meet commercial demands. Considering that spinel-type LiMn₂O₄ has been shown to be a successful Li intercalation host, spinel-like ZnMn₂O₄ (ZMO) is expected to be a good candidate for ZIBs cathodes. This paper first introduces the zinc storage mechanism of ZMO and then reviews the promotion of research progress in improving the interlayer spacing, structural stability, and diffusivity of ZMO, including the introduction of different intercalated ions, introduction of defects, and design of different morphologies and in combination with other materials. The development status and future research directions of ZMO-based ZIBs characterization and analysis techniques are summarized.

Layered-Oxide Cathode Materials for Fast-Charging Lithium-Ion Batteries: A Review

Layered oxides are considered prospective state-of-the-art cathode materials for fast-charging lithium-ion batteries (LIBs) owning to their economic effectiveness, high energy density, and environmentally friendly nature. Nonetheless, layered oxides experience thermal runaway, capacity decay, and voltage decay during fast charging. This article summarizes various modifications recently implemented in the fast charging of LIB cathode materials, including component improvement, morphology control, ion doping, surface coating, and composite structure. The development direction of layered-oxide cathodes is summarized based on research progress. Further, possible strategies and future development directions of layered-oxide cathodes to improve fast-charging performance are proposed.

Inhibitory behavior and adsorption of asparagine dipeptide amino acid on the Fe(111) surface

CONTEXT

The inhibitory effect of asparagine (Asn) and its derivatives on iron (Fe) corrosion was studied by performing density functional theory (DFT) calculations. In this paper, the global and local reactivity descriptors of Asn in the protonated and neutral forms were evaluated. Also, the changes in reactivity were investigated when dipeptides were combined with Asn. Due to the increase in the reaction centers within their molecular structure, there was an enhancement in the inhibitory effect of these dipeptides. Moreover, the adsorption energies (E_ads) and the adsorption configurations of Asn and small peptides (SPs) with most stability were determined on the surface of Fe(111). It was found that dipeptides had a chemical adsorption on these substrates. In the protonated forms, there was an enhancement in the absolute values of E_ads between the inhibitors and the Fe(111) surfaces. Peptides were more likely to be adsorbed on the Fe surfaces, showing the great inhibitory effect of these moieties. The results of the current research demonstrate the possibility of utilizing SPs as efficient "green" corrosion inhibitors.

METHODS

DFT computations were undertaken by employing the BIOVIA Material Studio with B3LYP-D3 functional and 6-31 + G* basis set. The theoretical evaluation of the inhibitory effect of asparagine (Asn) dipeptides, and the potential analysis of small peptides to protect against the corrosion of Fe, was done.

Exploring the role of 2D-C2N monolayers in potassium ion batteries

CONTEXT

In recent years, undivided attention has been given to the unique properties of layered nitrogenated holey graphene (C₂N) monolayers (C₂NMLs), which have widespread applications (e.g., in catalysis and metal-ion batteries). Nevertheless, the scarcity and impurity of C₂NMLs in experiments and the ineffective technique of adsorbing a single atom on the surface of C₂NMLs have significantly limited their investigation and thus their development. Within this research study, we proposed a novel model, i.e., atom pair adsorption, to inspect the potential use of a C₂NML anode material for KIBs through first-principles (DFT) computations. The maximum theoretical capacity of K ions reached 2397 mA h g^-1, which was greater in contrast with that of graphite. The results of Bader charge analysis and charge density difference revealed the creation of channels between K atoms and the C₂NML for electron transport, which increased the interactions between them. The fast process of charge and discharge in the battery was due to the metallicity of the complex of C₂NML/K ions and because the diffusion barrier of K ions on the C₂NML was low. Moreover, the C₂NML has the advantages of great cycling stability and low open-circuit voltage (approximately 0.423 V). The current work can provide useful insights into the design of energy storage materials with high efficiency.

METHODS

In this research, we used B3LYP-D3 functional and 6-31 + G* basis with GAMESS program to calculate adsorption energy, open-circuit voltage, and maximum theoretical capacity of K ions on the C₂NML.