Rechargeable Metal Research Articles

Regulating the Zn electrode/electrolyte interface with lactose additive for high performance Zn anode

The practical utilization of rechargeable aqueous zinc metal batteries (AZMBs) has been constrained by the formation of zinc dendrites and other associated issues. This article introduces lactose, a compound rich in hydroxyl groups, as an electrolyte additive into the aqueous solution of the electrolyte with the objective of suppressing the harmful growth of zinc dendrites. The lactose additive, with its strong zincophilicity, robust intermolecular hydrogen bonding, and a large number of exposed high electronegativity hydroxyl groups, enables lactose to effectively modulate the electrode/electrolyte interface in a dynamic manner, thereby achieving the stability and reversibility of the zinc anode. The findings presented in this work demonstrate the uniform deposition and stripping of zinc in a 2 M ZnSO4 electrolyte with the addition of lactose, thereby enhancing the cycling performance of Zn||Zn batteries. The alteration of the zinc ion environment on the surface of the zinc electrode, in conjunction with the dynamic modulation of the Gouy-Chapman-Stern (GCS) layer by lactose, increases the nucleation overpotential, thereby facilitating to a uniform deposition morphology in lieu of the formation of large-scale dendrites. Furthermore, the formation of hydrogen bonds serves to prevent the occurrence of side reactions. These factors act in concert to enhance the electrochemical performance of AZMBs. The addition of lactose to the electrolyte has resulted in a significant enhancement in the Coulombic efficiency of the card-type Zn||Cu asymmetric battery, reaching 99.7 %. The biodegradability of lactose and the sustainability of its source make this research conducive to the development of environmentally friendly battery electrolyte additives.

Self-Templated 3D Sulfide-Based Solid Composite Electrolyte for Solid-State Sodium Metal Batteries.

Rechargeable solid-state sodium metal batteries (SSMBs) experience growing attention owing to the increased energy density (vs Na-ion batteries) and cost-effective materials. Inorganic sulfide-based Na-ion conductors also possess significant potential as promising solid electrolytes (SEs) in SSMBs. Nevertheless, due to the highly reactive Na metal, poor interface compatibility is the biggest obstacle for inorganic sulfide solid electrolytes such as Na3SbS4 to achieve high performance in SSMBs. To address such electrochemical instability at the interface, new design of sulfide SE nanostructures and interface engineering are highly essential. In this work, a facile and straightforward approach is reported to prepare 3D sulfide-based solid composite electrolytes (SCEs), which utilize porous Na3SbS4 (NSS) as a self-templated framework and fill with a phase transition polymer. The 3D structured SCEs display obviously improved interface stability toward Na metal than pristine sulfide. The assembled SSMBs (with TiS2 or FeS2 as cathodes) deliver outstanding electrochemical cycling performance. Moreover, the cycling of high-voltage oxide cathode Na0.67Ni0.33Mn0.67O2 (NNMO) is also demonstrated in SSMBs using 3D sulfide-based SCEs. This study presents a novel design on the self-templated nanostructure of SCEs, paving the way for the advancement of high-energy sodium metal batteries.

Microporous Polyethylene and Cellulose Composite Separators for Reversible Lithium Electrode in Lithium Rechargeable Batteries

AbstractThe lithium metal anode is the best candidate for high energy density batteries because of its high specific capacity and low negative potential. Rechargeable lithium metal batteries (RLMB) have not yet been commercialized. The key factors that limit the practical use of RLMB are the formation and growth of lithium dendrites during the lithium deposition process and the reaction of the lithium anode with the organic solvent of the electrolyte, quantified by the Columbic efficiency (CE). To suppress the lithium dendrite formation and to improve CE, many approaches such as the formation of a protective layer on the lithium electrode and the use of additives to the electrolyte have been proposed. In this study, the effect of a thin cellulose film to improve CE of lithium deposition and stripping on the lithium electrode was examined. The cycle performance of a Li/Li symmetrical cell with a cellulose and polyethylene composite separator was examined for a carbonate electrolyte and an ether electrolyte. The improvements of CE were observed for both electrolytes with the cellulose film separator. The improvement could be explained by the good wettability of the cellulose film separator with the electrolyte.

Stabilization Strategies of Lithium Metal Anode Toward Dendrite-Free Lithium-Sulfur Batteries.

Lithium-sulfur (Li-S) batteries are considered as a most promising rechargeable lithium metal batteries because of their high energy density and low cost. However, the Li-S batteries mainly suffer the capacity decay issue caused by the shutting effect of lithium polysulfides and the safety issues arising from the Li dendrites formation. This review outlines the current issues of Li-S batteries. Furthermore, we comprehensively summarized the challenges encountered by Li anode in Li-S batteries, such as the heterogeneous deposition of the Li anode, the unstable solid electrolyte interface (SEI) layer, and volume expansion. Moreover, research progresses in the stabilization strategies of Li anodes (physical approaches, optimization of electrolyte, surface protection layer, and design of current collector) is discussed in detail. Lastly, the remaining challenges and future research directions of Li metal anode stabilization in Li-S batteries are also present.

ZnO Nanoparticle Assisted Liquid Metal for Dendrite-Free Zn Metal Anodes.

Dendrite growth and interfacial side reactions on Zn anode seriously affect the safety and service life of Zn ions batteries. Interface engineering is an effective way to solve these problems. Here, a liquid metal-ZnO composite coating with high ionic conductivity is creatively designed, which not only reduces the Zn2+ diffusion barrier but also increases the hydrogen evolution overpotential, thereby eliminating dendrite growth behavior and corrosion on the modified Zn anode. Moreover, its unique structure induces Zn deposition into the inner of coating, which can effectively avoid the volume expansion in the deposit layer of Zn anode. Therefore, it can cycle for 3000 h at an ultra-small polarization of 28 mV at 1 mA cm-2, and the microbattery assembled in combination with the MnO2 cathode also maintains 2000 cycles with high Coulomb efficiency, providing a general idea for the development of the next generation of rechargeable metal batteries.

Super SEI-Forming Anion for Enhanced Interfacial Stability in Solid-State Lithium Metal Batteries.

The extremely high chemical reactivity of lithium metal (Li°) electrodes and its enormous volume change during repetitive cycles cause continuous interfacial degradations in prevailing organic electrolytes, thus deteriorating the cycling performances of rechargeable lithium metal batteries (LMBs). Herein, departing from traditional wisdom on the design of electrolyte components, a super SEI-forming anion (SSA), as an efficient percussor for building stable interphases on Li° electrode, is proposed. Comprehensive investigations related to the unique anion chemistry of SSA reveal that the sulfonate and polyfluoroalkyl functionalities synergistically contribute to uniform spatial distributions of designer interfacial species, greatly improving the surface coverage property and conformal ability of the resulting interphases. Consequently, the incorporation of SSA leads to significant improvements in the cyclability of Li° electrode (exceeding 575 mAh cm-2 before failure) and the corresponding rechargeable Li°||LiFePO4 cells [a five-time increase in lifespan as compared to the benchmark cell with the popular SEI-forming anion bis(fluorosulfonyl)imide (FSI)]. The present work offers a paradigm shift to tame the notorious interfacial issues via upgraded anion chemistry, which can promote the practical development of rechargeable LMBs and other kinds of metal batteries.

Challenges and Progress in Anode‐Electrolyte Interfaces for Rechargeable Divalent Metal Batteries (Adv. Energy Mater. 38/2024)

Challenges and Progress in Anode‐Electrolyte Interfaces for Rechargeable Divalent Metal Batteries (Adv. Energy Mater. 38/2024)

Recent advances in functionalized separator for dendrites‐free and stable lithium metal batteries

AbstractLithium (Li) metal anode is considered the “Holy grail” for the most promising next‐generation rechargeable lithium metal batteries (LMBs) because of ultra‐high theoretical specific capacity, ultra‐low reduction potential and small density. However, uncontrolled lithium dendrite growth and inevitable side reaction seriously hindered the application of practical LMBs because of the deteriorating electrochemical performances and exacerbating the safety issues of LMBs. Thus, improving the electrochemical performances of LMBs by constructed of functionalized separator is promising for overcoming the above‐mentioned challenges due to its' significantly advantages, such as enhancing mechanical and thermal stability, regulating the diffusion and migration of Li ions, homogenizing Li ion flux, forming protective layer on Li anode surfaces, etc. The relational investigations have significantly increased since 2020, while the comprehensive reviews on this research direction are relatively rare, especially in the detailed mechanism aspects. In this review, an overview in functionalized separator for stable LMBs is discussed in detail. Firstly, the current issues of LMBs are in‐depth discussion and the general strategies are summarized. Subsequently, the requirements and limitations of separator, as well as the advantages of functionalized separator are summarized and reviewed. Most importantly, the protection mechanisms and research advances of advanced functionalized separator are comprehensively discussed and summarized. Furthermore, the applications of functionalized separator in rechargeable lithium metal‐based full cells are reviewed. Finally, the challenges and potential opportunities for the future development and rational design of functionalized separator are highlighted in rechargeable LMBs to obtain future research directions related to the significant strategy of constructing dendrite‐free and stable LMBs.

Interlayer Space Engineering-Induced Pseudocapacitive Zinc-Ion Storage in Holey Graphene Oxide-Bearing Vertically Oriented MoS2 Nano-Wall Array Cathode for Aqueous Rechargeable Zn Metal Batteries.

Transition metal dichalcogenides, particularly MoS2, are acknowledged as a promising cathode material for aqueous rechargeable zinc metal batteries (ARZMBs). Nevertheless, its lack of hydrophilicity, poor electrical conductivity, significant restacking, and restricted interlayer spacing translate into inadequate capacity and rate performance. Herein, the unique porous structure and additional functional groups present in holey graphene oxide (hGO) are taken advantage of to dictate the vertical growth pattern of oxygen-doped MoS2 nanowalls (O-MoS2/NW) over the hGO surface. Compared to conventional graphene oxide (GO), the presence of nano-pores in hGO facilitates the homogeneous dispersion of Mo precursors and provides stronger interaction sites, promoting the uniform vertical alignment of O-MoS2/NW. The synergistic interaction between O-MoS2-NW and hGO translates to enhanced electron conductivity, efficient electrolyte penetration, enhanced interlayer spacing, reduced restacking, and enhanced surface area. As a consequence of precise control of various factors that decide the overall battery performance, a high discharge capacity (227mAhg-1 at 100mAg-1) cathode material with significantly lower charge transfer resistance (66Ω) compared to pristine O-MoS2 (153Ω) is developed. These findings underscore the potential of hGO as a multifunctional platform for nanoengineering high-performance cathode materials for the next generation of efficient and durable ARZMBs.

Self-grown carbon nanotubes supported fluorine-free Mo2CTx conductive layers for efficient potassium storage

Mo2CTx is relatively less studied among MXenes family, especially for rechargeable alkali metal ion batteries. Herein, a systematic investigation has been conducted to unlock its potential as electrode materials in potassium-ion battery (PIBs), including innovative fluorine-free synthesis strategy, construction of heterostructure, and exploration of suitable electrolyte systems. Firstly, Cetyltriethylammnonium bromide (CTAB)-assisted etching route was provided to fabricate high-quality multilayer Mo2CTx with expanded interlayer space (C-Mo2CTx). The as-obtained C-Mo2CTx demonstrates a large specific capacity of 200 mAh g−1over 300 cycles in potassium-ion battery, surpassing the HF etched counterparts (F-Mo2CTx) by about 300 %. Afterwards, Zeolitic Imidazolate Frameworks (ZIF-67) derived Co, N-codoped carbon nanotubes (Co@NCNTs) were homogenously grown on the surface of Mo2CTx, working as embedding spacer to open the stacked Mo2CTx conductive layers (Mo2CTx-Co@NCNTs). Mo2CTx-Co@NCNTs electrode represents stable reversible capacity of 280 mA h g−1 over 300 cycles. The highly conductive matrix constructed by the strong bond between CNTs arrays and Mo2CTx conductive layer could provide numerous K-ion-diffusion pathways, and buffer volume strain and facilitate electron transfer. The present work proves the potential of Mo2CTx in PIBs and gives the systematic research methodologies on Mo2CTx-based materials in alkali metal ion storage.

Advances in Functional Organosulfur-Based Mediators for Regulating Performance of Lithium Metal Batteries.

Rechargeable lithium metal batteries (LMBs) are promising next-generation energy storage systems due to their high theoretical energy density. However, their practical applications are hindered by lithium dendrite growth and various intricate issues associated with the cathodes. These challenges can be mitigated by using organosulfur-based mediators (OSMs), which offer the advantages of abundance, tailorable structures, and unique functional adaptability. These features enable the rational design of targeted functionalities, enhance the interfacial stability of the lithium anode and cathode, and accelerate the redox kinetics of electrodes via alternative reaction pathways, thereby effectively improving the performance of LMBs. Unlike the extensively explored field of organosulfur cathode materials, OSMs have garnered little attention. This review systematically summarizes recent advancements in OSMs for various LMB systems, including lithium-sulfur, lithium-selenium, lithium-oxygen, lithium-intercalation cathode batteries, and other LMB systems. It briefly elucidates the operating principles of these LMB systems, the regulatory mechanisms of the corresponding OSMs, and the fundamentals of OSMs activity. Ultimately, strategic optimizations are proposed for designing novel OSMs, advanced mechanism investigation, expanded applications, and the development of safe battery systems, thereby providing directions to narrow the gap between rational modulation of organosulfur compounds and their practical implementation in batteries.

Interfacial electronic insulation strategy for high-performance Zinc-ion batteries

Aqueous rechargeable zinc metal batteries have garnered widespread attention due to their inherent high safety, high volumetric capacity, and low cost. However, the uncontrollable growth of zinc dendrites and severe hydrogen evolution reaction (HER) side reactions lead to low Coulombic efficiency and short lifespan of zinc metal anodes, hindering their practical application. We employed a plasma fluorination strategy to in-situ react on the surface of zinc metal to generate an electron-insulating ZnF2 coating, which reduces HER, suppresses dendrite growth, and enhances the wettability of the electrode with the electrolyte. Through density functional theory (DFT) and molecular dynamics (MD) simulations, we systematically studied the mechanism by which ZnF2 improves interfacial properties, suppresses the hydrogen evolution reaction (HER), and inhibits dendrite formation. Ultimately, symmetric batteries and Zn@ZnF2||Cu batteries assembled with Zn@ZnF2 electrodes exhibited significantly extended cycle life and high Coulombic efficiency. Full cells of Zn@ZnF2||MnO2@CNT achieved a cycle life of over 5000 cycles at a current density of 1 A g−1. This study provides a practical method for industrial treatment of the Zn surface and offers an in-depth analysis and discussion of the role of ZnF2 in inhibiting dendrite growth, HER, and improving interfacial wettability in zinc-ion batteries.

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.

In Situ Formed Gel Polymer Electrolytes Enable Stable Solid Electrolyte Interface for High-Performance Lithium Metal Batteries.

Carbonate-based electrolytes show distinct advantages in high-voltage cathodes but generate nonuniform and mechanically fragile solid-electrolyte interphase (SEI) in lithium (Li) metal batteries. Herein, we propose a LiF-rich SEI incorporating an in situ polymerized poly(hexamethylene diisocyanate)-based gel polymer electrolyte (GPE) to improve the homogeneity and mechanical stability of SEI. Fluoroethylene carbonate (FEC) as a fluorine-based additive for building LiF-rich SEI on Li metal electrodes. With this strategy, the assembled Li symmetric batteries cycled stably for 700 h, and the formation of byproducts on the Li electrode surface was significantly inhibited. The Li/LiFePO4 battery delivered significant capacity retention (91% retention after 800 cycles) at 1 C. With high-voltage LiNi0.8Co0.1Mn0.1O2 (NCM811) as cathode, the Li/GPE-FEC/NCM811 cell delivered a discharge capacity of 168.9 mAh g-1 with a capacity retention of 82% after 300 cycles at 0.5 C. From the above, the work could assist the rapid development of high-energy-density rechargeable Li metal batteries toward remarkable performance.

Monoclinic Silver Vanadate (Ag0.33V2O5) as a High-Capacity Stable Cathode Material for Aqueous Manganese Batteries.

Aqueous rechargeable metal batteries have recently garnered considerable attention owing to their low cost, sufficient capacity, and the use of non-flammable water-based electrolytes. Among them, manganese batteries are particularly favored because of their stability, abundance, affordability, and high energy density. Despite their advantages, Mn storage host structures remain underexplored. Therefore, developing innovative host materials is crucial for advancing this field. In this paper, the study reports for the first time, the use of Ag0.33V2O5 as a cathode material in aqueous manganese batteries. The study explains the displacement/intercalation behavior of manganese and silver using electrochemical, structural, and spectroscopic analyses. Additionally, it is shown that cation (Ag+, Mn2+, H+) diffusion pathways can be simulated using diffusion-barrier calculations. Finally, the study demonstrates high-performance manganese batteries that exhibit a remarkable reversible capacity of ≈261.9 mAhg-1 at a current of 0.1 Ag-1 and an excellent cycle retention of 69.1% after 2000 cycles at a current density of 1.5 A/g. The findings of this study contribute to the advancement of aqueous manganese battery technology, offering a promising pathway for developing safer, more cost-effective, and high-performance energy storage systems.

(Invited) Electrolyte Design for Wide-Temperature Lithium Batteries

Improving the wide temperature performance of rechargeable batteries is vital to the operation of electronics and vehicles in extreme environments, where systems capable of higher energy, high-rate discharge and long cycling are in short supply. In this talk, we will show electrolyte designs to achieve high-energy density and stable cycling performance in wide temperature range, especially in extremely low-temperature environment. We will use a few examples, including ester- and ether-based electrolyte with different concentrations to showcase the critical role of solvation and desolvation in determining the charge-transfer kinetics at low-temperature. We will also discuss the role of solvation structure in shaping interfacial stability in different cathode and anode systems. These fundamental understanding may provide viable design strategies for high energy density and long-life batteries for both high and extremely low temperatures such as rechargeable Li metal batteries using both high-Ni oxide and sulfur cathodes.

(Invited) Recycling Zn for Rechargeable Zinc-Ion Batteries

Aqueous energy storage devices require highly reversible Zn electrodes, but this has been impeded by challenges including dendrite growth, low efficiency, hydrogen evolution, and metal corrosion. Here, we have successfully fabricated a reversible Zn powder electrode via engineering the growth of zinc crystals in different solvents from spent Zn foils. Theoretical calculations demonstrate that the adsorption energy gap of different solvents on the (002) or (100) facet of Zn metal varies and that a larger energy gap favors a higher orientation of Zn (002) plane. Highly oriented Zn (002) powder exhibits horizontal deposition, corrosion resistance, faster kinetics, and longer life under deep discharge (60%) in symmetric cells compared with less-oriented Zn. Under practical conditions including low N/P ratios (1–3), high-loading cathodes (10–18 mg cm−2), and lean electrolyte (5–9 μL mg−1), highly (002)-oriented Zn powder-based batteries and supercapacitors demonstrate large capacity (∼3 mAh cm−2) and energy/power density (108 Wh kg−1/2,317 W kg−1), holding promise for applications. And for the first time, we have also upcycled spent alkaline batteries into rechargeable Zn metal batteries through a simple thermal treatment of electrode waste. The regenerated Zn powder anode shows super-zincophilicity and low overpotentials even under fast rates (8 mA cm−2) and high depth-of-discharge (50 %), which can be ascribed to coating of hydroxyl-rich organic layer with abundant nucleation sites as well as high orientation of favorable (002) plane and induced horizontal plating behavior. The regenerated cathode composed of MnO2 and MnOOH manifests enhanced capacity in comparison to pristine ones. Under a low negative-to-positive capacity ratio of 3.8 and high loading of ~10 mg cm−2, the regenerated electrodes are paired to fabricate zinc metal batteries which demonstrate high energy and power densities (94 Wh kg−1, 1349 W kg−1), holding potential for practical applications. Given the sustainable, low-cost, environmental-friendly, and value-added features, the strategy proposed here will open a new pathway toward battery recycling/upcycling.

Designing Interphases in Zn and Al Aqueous Electrolytes

This talk will cover two recent studies led by the Army Research Laboratory investigating interphase formation and cation solvation in zinc and aluminum aqueous electrolytes, respectively. In the former, two co-cations were carefully designed to offer distinct, complementary improvements in aqueous Zn electrolytes: a partially fluorinated pyrrolidinium cation effectively suppresses parasitic reactions such as hydrogen evolution (< 6 µA cm-2), and an ether-functionalized ammonium cation inhibits dendrite formation (almost 10 Ah cm-2 cumulative capacity, > 1 year, Zn||Zn). In the later, transient electrostatic hydrolysis of Al-OH2 ligands, without Al-OTf contact ion pairs, leads to insufficient reductive stability for rechargeable metal anodes. These contrasting systems provide helpful guidance for designing aqueous electrolytes with energy-dense multivalent metal anodes.

A Redox-Active Iron-Organic Framework Cathodes for Sustainable Magnesium Metal Batteries.

Rechargeable magnesium metal batteries (RMBs) have shown promising prospects in sustainable energy storage due to the high crustal abundance, safety, and potentially large specific capacity of magnesium. However, their development is constrained by the lack of effective cathode materials that can achieve high capacity and stable magnesium storage at a practically reasonable rate. Herein, we construct a three-dimensional (3D) iron(III)-dihydroxy-benzoquinone (Fe2(DHBQ)3) metal-organic framework (MOF) material with dual redox centers of Fe3+ cations and DHBQ2- anions for reversible storage of Mg2+ in RMBs. Spectroscopic analysis and density functional theory (DFT) calculations reveal the redox chemistry of both Fe3+ ions and carbonyls from DHBQ ligands during electrochemical processes. Benefiting from the rational structure, the Fe2(DHBQ)3∥Mg cells exhibit a high reversible capacity of 395.3 mAh/g, large energy density of 463.5 Wh/kg, and high power density of 2456.0 W/kg. Moreover, the high electronic conductivity (8.35 × 10-5 S/cm) and favorable diffusion path of Mg2+ in Fe2(DHBQ)3 endow the cells with exceptional cycling stability and rate capability with a long life of 5000 cycles at 2000 mA/g. The dual redox-active MOF demonstrates a category of advanced cathode materials for high-performance RMBs.

Salt-Assisted Recovery of Sodium Metal Anodes for High-Rate Capability Sodium Batteries.

Rechargeable sodium metal batteries are considered to be one of the most promising high energy density and cost-effective electrochemical energy storage systems. However, their practicality is constrained by the high reactivity of sodium metal anodes that readily brings about excessive accumulation of inactive Na species on the surface, either by chemical reactions with oxygen and moisture during electrode handling or through electrochemical processes with electrolytes during battery operation. Herein, this paper reports on an alkali, salt-assisted, assembly-polymerization strategy to recover Na activity and to reinforce the solid-electrolyte interphase (SEI) of sodium metal anodes. To achieve this, an alkali-reactive coupling agent 3-glycidoxypropyltrimethoxysilane (GPTMS) is applied to convert inactive Na species into Si-O-Na coordination with a self-assembly GPTMS layer that consists of inner O-Si-O networks and outer hydrophobic epoxides. As a result, the electrochemical activity of Na metal anodes can be fully recovered and the robust GPTMS-derived SEI layer ensures high capacity and long-term cycling under an ultrahigh rate of 30 C (93.1 mAh g-1, 94.8% after 3000 cycles). This novel process provides surface engineering clues on designing high power density and cost-effective alkaline metal batteries.