Metal Anode Research Articles

Highly Effective Polyacrylonitrile-Rich Artificial Solid-Electrolyte-Interphase for Dendrite-Free Li-Metal/Solid-State Battery.

Lithium metal anode batteries have attracted significant attention as a promising energy storage technology, offering a high theoretical specific capacity and a low electrochemical potential. Utilizing lithium metal as the anode material can substantially increase energy density compared with conventional lithium-ion batteries. However, the practical application of lithium metal anodes has encountered notable challenges, primarily due to the formation of dendritic structures during cycling. These dendrites pose safety risks and degrade battery performance. Addressing these challenges necessitates the development of a reliable and effective protection layer for lithium metal. This study presents a cost-effective and convenient method to spontaneously produce lithium metal protective layers by creating polymeric layers by using acrylonitrile (AN). This method remarkably extends 6× of the lifetime of lithium metal anodes under high current density (1 mA/cm2) cycling conditions. While the cycle life of bare lithium metal is approximately 150 h under high current cycling conditions, AN-treated lithium metal anodes exhibit an impressive longevity of over 900 h. The AN-treated lithium metal anodes are further integrated and tested with sulfide-based Li10GeP2S12 (LGPS) solid-state electrolytes to evaluate its interfacial stability at a solid-solid interface. The formation of the polyacrylonitrile (PAN)-rich ASEI, due to AN-treatment, effectively reduces and stabilizes the cell overpotential to only one-tenth of that with the interface without treatment. This strategy paves a route to enable a highly efficient and highly stable Li/LGPS solid-state battery interface.

Molecular Chain Rearrangement of Natural Cellulose‐based Artificial Interphase for Ultra‐stable Zn Metal Anodes

The unstable electrolyte‐anode interface, plagued by parasitic side reactions and uncontrollable dendrite growth, severely hampers the practical implementation of aqueous zinc‐ion batteries. To address these challenges, we developed a regenerated cellulose‐based artificial interphase with synergistically optimized structure and surface chemistry on the Zn anode (RC@Zn), using a facile molecular chain rearrangement strategy. This RC interphase features a drastically increased amorphous region and more exposed active hydroxyl groups, facilitating rapid Zn2+ diffusion and homogeneous Zn2+ interface distribution, thereby enabling dendrite‐free Zn deposition. Additionally, the compact texture and abundant negatively charged surface of the RC interphase effectively shield water molecules and harmful anions, completely preventing H2 evolution and Zn corrosion. The superior mechanical strength and adhesion of the RC interphase also accommodate the substantial volume changes of Zn anodes even under deep cycling conditions. Consequently, the RC@Zn electrode demonstrates an outstanding cycling lifespan of over 8000 hours at a high current density of 10 mA cm‐2. Significantly, the electrode maintains stable cycling even at a 90% depth of discharge and ensures stable operation of full cells with a low negative/positive capacity ratio of 1.6. This study provides new solution to construct highly stable and deep cycling Zn metal anodes through interface engineering.

Synergistic Regulation of Anode and Cathode Interphases via an Alum Electrolyte Additive for High‐Performance Aqueous Zinc‐Vanadium Batteries

AbstractA zinc (Zn) metal anode paired with a vanadium oxide (VOx) cathode is a promising system for aqueous Zn–ion batteries (AZIBs); however, side reactions proliferating on the Zn anode surface and the infinite dissolution of the VOx cathode destabilise the battery system. Here, we introduce a multi‐functional additive into the ZnSO4 (ZS) electrolyte, KAl(SO4)2 (KASO), to synchronise the in situ construction of the protective layer on the surface of the Zn anode and the VOx cathode. Theoretical calculations and synchrotron radiation have verified that the high‐valence Al3+ plays dual roles of competing with Zn2+ for solvation and forming a Zn−Al alloy layer with a homogeneous electric field on the anode surface to mitigate the side reactions and dendrite generation. The Al‐containing cathode–electrolyte interface (CEI) considerably alleviates the irreversible dissolution of the VOx cathode and the accumulation of byproducts. Consequently, the Zn||Zn cell with KASO exhibits an ultra‐long cycle of 6000 h at 2 mA cm−2. Importantly, the VOx cathodes (VO2, V2O5 and NH4V4O10) in the ZS−KASO electrolyte showed excellent cycling stability, including Zn powder||VO2 cells and Zn||VO2 pouch cells. Even better, the full cell exhibits excellent cycling stability at low negative/positive (N/P) ratio of 2.83 and high mass loading (~16 mg cm−2). This study offers a straightforward and practical reference for concurrently addressing challenges at the anode and cathode of AZIBs.

Manipulation in the In Situ Growth Design Parameters of Aqueous Zinc‐Based Electrodes for Batteries: The Fundamentals and Perspectives

ABSTRACTPrecise exploitation of the growth of Zn metal anode in a power converter system has re‐emerged as one of the technological interests that have surged globally in the past 5 years, specifically to improve the practical use of deep cycling metal batteries. In this review, the in situ architectures of aqueous Zn metal‐based batteries focusing on the intrinsic geometrical building block and their respective mode of assembly classifying the deposition morphologies are scrutinised and discussed. The fundamental electrochemical kinetic principles and the associated critical issues, especially associated with the metal plague deposition that influences the morphology of deposited Zn, are considered. Also, the growing interest in the interphase system, which has an intense influence in characterising the types of Zn deposition morphology, is included. Consideration of the fundamental crystal features of Zn, endowing the predominant key for its growth assembly, is provided. Last, the review offers perspectives on the current progress of Zn–Air batteries in the application of electric vehicles.

Molecular Chain Rearrangement of Natural Cellulose-based Artificial Interphase for Ultra-stable Zn Metal Anodes.

The unstable electrolyte-anode interface, plagued by parasitic side reactions and uncontrollable dendrite growth, severely hampers the practical implementation of aqueous zinc-ion batteries. To address these challenges, we developed a regenerated cellulose-based artificial interphase with synergistically optimized structure and surface chemistry on the Zn anode (RC@Zn), using a facile molecular chain rearrangement strategy. This RC interphase features a drastically increased amorphous region and more exposed active hydroxyl groups, facilitating rapid Zn2+ diffusionand homogeneous Zn2+ interface distribution, thereby enabling dendrite-free Zn deposition. Additionally, the compact texture and abundant negatively charged surface of the RC interphase effectively shield water molecules and harmful anions, completely preventing H2 evolution and Zn corrosion. The superior mechanical strength and adhesion of the RC interphase also accommodate the substantial volume changes of Zn anodes even under deep cycling conditions. Consequently,the RC@Zn electrode demonstrates an outstanding cycling lifespan of over 8000 hours at a high current density of 10 mA cm-2. Significantly, the electrode maintains stable cycling even at a 90% depth of discharge and ensures stable operation of full cells with a low negative/positive capacity ratio of 1.6. This study provides new solution to construct highly stable and deep cycling Zn metal anodes through interface engineering.

The Mechanism of Aluminum Deposition and Dendrite Growth on a Copper Substrate in Anode-Free Aluminum Batteries.

Given the critical demand for batteries with a high energy density and the global scarcity of lithium, anode-free aluminum batteries (AFABs) have attracted significant attention. AFABs utilize collectors instead of traditional anode metal foils, eliminating the need for anode materials and significantly enhancing the energy density of the batteries. However, the proliferation of aluminum dendrites might cause safety risks and reduce Coulombic efficiency, possibly impeding commercialization. This study employs molecular dynamics (MD) simulations to explore the deposition mechanisms of aluminum (Al) on copper (Cu) collectors and the dynamics of aluminum dendrite growth under nonhomogeneous deposition conditions. The results indicate that the surface properties of the Cu substrate significantly affect aluminum deposition, leading to more homogeneous and amorphous deposition on Cu(110) surfaces. However, the FCC structure of Al atoms on the Cu(111) surfaces exhibited the largest number. Strategically increasing the temperature and pressure can effectively prevent the formation of aluminum dendrites. The results are helpful for enhancing the battery cycle stability and the application of novel AFABs.

A Synergistic Zincophilic and Hydrophobic Supramolecule Shielding Layer for Actualizing Long‐Term Zinc‐Ion Batteries

AbstractThe zinc metal anodes are liable to experience detrimental dendrite growth and side reactions, thereby limiting the lifespan of aqueous Zn‐ion batteries. Here, a readily available supramolecule, dimethoxypillar[5]arene (DP[5]), is utilized as a shielding layer to stabilize the Zn anode by exploiting its zincophilicity derived from the ─OCH3 functional groups and its hydrophobicity from the hydrophobic backbone. The DP[5] shielding layer regulates the solvation sheath of Zn2+ and facilitates uniform zinc deposition. Swelling and dendrite formation are obviously suppressed in both the symmetric and full cells. The DP[5]‐Zn symmetrical cell cycles stably for 5500 h, and achieves a coulombic efficiency of 99.76% in a DP[5]‐Zn||Cu half‐cell after 2200 cycles. The DP[5]‐Zn||V2O5 full cell maintains 92.03% of initial capacity after 6000 cycles. Given the cost‐effective fabrication and environmental friendliness of DP[5] films, this material may pave the way for practical applications of zinc anodes.

Regulating of Lithium‐Ion Dynamic Trajectory by Ferromagnetic CoF2 to Achieve Ultra‐Stable Deep Lithium Deposition Over 10000 h

AbstractCurrently, the realization of controllable Li electrodeposits to further extend the cycling life of Li metal anode remains challenging. Herein, it is reported that carbon nanosheet array‐loaded ferromagnetic CoF2 nanoparticles on carbon cloth (CC@CoF2/C) as an internal micro‐magnetic field source to manipulate the dynamic trajectory of Li+ deposition via the magnetohydrodynamic effect. This approach ensures uniform lithium‐ion distribution and improves deep plating capacity, achieving a prolonged cycle life of the dendrite‐free Li anode. Finite element simulations, in situ characterizations, and electrochemical tests confirm that magnetic CoF2 not only guides Li+ migration through Lorentz force to prevent dendritic growth but also improves uniform Li deposition due to the in situ conversion of LiF‐rich solid electrolyte interphase during electroplating. Meanwhile, a CC@CoF2/C‐based half‐cell operates stably over 10 000 h at 1 mA cm−2 with a low 7.8 mV overpotential. When matched with a commercial LiFePO4 cathode, the full cell reveals a high capacity of 122.96 mAh g−1 at a 2 C rate after 1000 cycles, retaining 91.95% capacity. The proposed strategy can be effectively expanded and adapted to investigate the deposition behavior of a wide range of metal anodes, offering a versatile and robust analytical framework for addressing diverse metal‐based electrochemical systems.

Bi-Functional Agarose-Filled Porous Polysulfone Protective Layer for Dendrite-Free Zn Anode.

The uneven electric field and slow Zn2+ desolvation lead to rapid dendrite growth during Zn plating and stripping, which severely deteriorates the performance of Zn metal anodes (ZMAs) in Zn-ion batteries (ZIBs). Although polymer-based artificial protective (PBAP) layers are widely applied to homogenize the electric field of ZMAs, they often fail to promote the desolvation process that eventually induces Zn dendrite growth. Herein, a bi-functional protective layer, comprising a finger-like porous matrix of polysulfone (PSF) and a hydroxyl-rich filler of agarose (AG), is constructed to suppress Zn dendrite growth. COMSOL simulation demonstrates the ZMAs with bi-functional protective layers (Zn@PSF/AG) exhibit uniform electric field and Zn2+ distribution. Besides, the Zn@PSF/AG has both low desolvation energy and nucleation overpotential, effectively promoting the desolvation of Zn2+. Therefore, the Zn@PSF/AG symmetric cell exhibits excellent cycling performance, achieving 4200h at 1mA cm-2/1 mAh cm-2 and 1000h at 5mA cm-2/5 mAh cm-2. When coupling with ZnxV2O5 (ZnVO) cathode, the ZnVO‖Zn@PSF/AG full cell shows similarly high cycling stability, maintaining 72% of its capacity after 7000 cycles at 10 A g-1. This research highlights the positive roles of PBAP layer with multi-functional matrix-filler structure in developing long-life ZIBs.

Functional Separator with Poly(Acrylic Acid)-Enabled Li2CO3-Free Garnet Coating for Long-Cycling Lithium Metal Batteries.

Lithium metal batteries (LMBs) possess a theoretical energy density far surpassing that of commercial lithium-ion batteries (LIBs), positioning them as one of the most promising next-generation energy storage systems. Modifying separators with composite coatings comprising oxide solid-state electrolyte (SSE) particles and polymers can improve the cycling stability and safety of LMBs. However, exposure to air forms Li2CO3 on oxide SSE particles, diminishing their ion flux regulation at the electrode/electrolyte interface. Utilizing the reaction of Li2CO3 with polyacrylic acid (PAA) to form lithium polyacrylate (LiPAA), an ultra-thin composite coating on polyethylene (PE) separator with Li2CO3-free Li6.4La3Zr1.4Ta0.6O12 (LLZTO) particles and LiPAA binder is fabricated in one step. The exposed Li2CO3-free LLZTO surface increases the ionic conductivity and lithium ion (Li+) transference number of the functional separator, resulting in small resistance and uniform Li deposition of the Li metal anode. Consequently, the Li//LiCoO2 cell with the functional separator exhibits a significantly improved life of 980 cycles with 80.9% capacity retention under lean-electrolyte conditions. Both the Li//LiCoO2 coin cell and pouch cell using thin Li foil anode demonstrate good cycling stability and high mechanical robustness. This study provides a green and scalable approach for fabricating advanced separators for LMBs.

Efficient sodium ion transport enhanced by anionophilic sites in polymer-supported plastic crystal electrolyte for high performance sodium metal anode

The design of sodium metal batteries (SMBs) is seen as an excellent solution to solve the request of next-generation energy storage technologies with high energy density, high safety, low cost, and environmental friendliness. However, the direct use of sodium metal as an anode produces the dendritic sodium, which harms the normal operation of battery. Inspired by solid-state lithium metal batteries, solid-state electrolyte (SSE) designed for SMBs effectively solves this shortcoming. Herein, a novel SSE with mask-based polymer membrane supporting plastic crystal electrolyte with ZIF-67 (MPPZ) is designed. The experimental results and density functional theory (DFT) calculations indicate that the addition of ZIF-67 in MPPZ electrolyte availably fixes TFSI− and achieves high Na+ transference number. Additionally, a protective layer of NaF is formed in situ on the surface of sodium metal to avoid side reactions between Na and MPPZ electrolyte while further guide the uniform deposition of Na. Accordingly, Na||Na symmetric battery with NaF-coated Na metal anode and MPPZ electrolyte has a stable deposition and stripping of Na for 3000 h. The assembled room temperature solid-state sodium-sulfur battery (RTSSSSB) exhibits a good cycle stability. This study provides an innovative thinking for the construction of high performance dendrite-free SMBs.

Navigating highly reversible Zn metal anodes via a multifunctional corrosion inhibitor-inspired electrolyte additive

Uncontrolled dendrites growth and irreversible side reactions on the Zn anode have greatly shorten the lifespan of aqueous zinc-ion batteries (ZIBs), thereby hindering their application as promising energy storage devices. Herein, inspired by the use of corrosion and scale inhibitors in metal industry, sodium gluconate (SG) is proposed as a multifunctional electrolyte additive to improve the reversible plating/stripping behavior on Zn metal anodes by simultaneously modulating Zn anode-electrolyte interface and the Zn deposition behaviors. Combining theoretical calculations and experimental characterizations, it shows that SG can protect the Zn anode against the corrosion side reactions and suppress the random growth of dendritic Zn by absorbing on the Zn anode surface to form an artificial interface layer. Concomitantly, the gluconate anion reshapes the solvation shell of Zn2+, influencing the desolvation process of Zn2+ and disrupting the formation of active water. Furthermore, Na+ originating from SG suppresses the dendritic Zn development in the light of electrostatic shielding mechanism. Benefiting from these synergetic effects of SG additive, Zn metal anodes achieve exceptional reversibility with prolonged running lifetime and increased coulombic efficiency and the Zn||V2O5 full cell demonstrates outstanding cycle stability. This strategy is scalable and low-cost, developing a promising approach to advance high-performance ZIBs.

Ordered mesoporous carbon–confined ZnO nanoparticles as a stable host for dendrite-free lithium metal anode

Ordered mesoporous carbon–confined ZnO nanoparticles as a stable host for dendrite-free lithium metal anode

Achieving the dendrite-free zinc anode by constructing a Sn-C interfacial layer with zincophilic and conductive network

Under the basic national policy of sustainable green development, high-performance and low-cost energy storage devices are urgently needed for intermittent generation of clean energy and storage of electrical energy. Zn metal with high capacity, abundant reserves and excellent plasticity, but the inevitable side reactions (hydrogen precipitation and corrosion, etc.) of the Zn metal anode itself have severely limited the development of aqueous Zn ion batteries (AZIBs) in the market. In this study, an artificial protective layer of polymer-derived carbon material combined with Sn is prepared to inhibit hydrogen precipitation and corrosion and prolong the lifetime of AZIBs. With these advantages, the Zn@Sn@N doped carbon (Zn@CNS) symmetric cell could achieve a stable cycle life of 1000 h at 2 mA cm-2 and low overpotential. The excellent stripping life of over 400 h is achieved in half-cells assembled with Cu foils. Furthermore, the α-MnO2//Zn@CNS full battery shows superior stability in rate capability and long-term capacity retention compared to the α-MnO2//Zn battery, indicating that the CNS coating provides excellent performance and practical value.

Fluorinated co-solvent electrolytes enable lithium metal batteries to operate at low temperatures

Enhancing the energy output of batteries in low temperatures is critical to broadening the application areas of advanced electronic devices, which can be accomplished by utilizing high-voltage cathodes to match lithium metal anode, optimizing electrolyte electrochemical windows and forming stable solid electrolyte interphases to provide facile ion-transmission kinetics at low temperature. Herein, we demonstrate a fluorinated ester co-solvent electrolyte, which applies 1 M LiPF6 in an ethyl 4,4,4-trifluoro butyrate/fluoroethylene carbonate (FEC) (4/1 by volume ratio) that jointly satisfies high voltage cathode and lithium metal anode reversibility at required ambient. The performance of the battery is due to the rapid dissociation of Li+ and the formation of a fluorine-rich inorganic electrolyte interface in the fluorinated solvent. Therefore, the fluorinated ester co-solvent electrolyte system can provide 209.9 mAh g−1, 194.8 mAh g−1, and 175.5 mAh g−1 when discharged at room temperature, −20 ℃ and −40 ℃, respectively, those far exceeds the performance of carbonate electrolytes. This work advances the development of low-temperature lithium metal batteries.

Iron-Free Anode Boosting High Energy Efficiency Aqueous Full Iron-Ion Batteries.

Aqueous iron-ion batteries with reversible storage of Fe2+ have undergone rapid development in recent years. Consistently throughout these studies, metallic iron is selected as the anode material. However, the large overpotential (250mV) associated with the plating/stripping process of iron in aqueous solutions leads to unsatisfactory energy efficiency of the battery, although high capacity and Coulomb efficiency can be achieved. Herein, an iron-free anode material, 9,10-anthraquinone (AQ) is proposed in aqueous iron-ion batteries, which shows a low reaction potential and minimal polarization during storing iron ions. The organic anode exhibits favorable specific capacity of 106mAhg-1 at 0.5Ag-1 and excellent cycling stability (92.6% retention after 500 cycles). In addition, an aqueous full iron-ion battery is constructed using AQ as the anode and 9,10-phenanthraquinone (PQ) as the cathode. The full battery demonstrates an enhanced energy efficiency of 72%, which is 206% higher than that of metal iron anode, and shows excellent cycling stability and Coulombic efficiency. This work provides a viable route to overcome the high polarization of metallic iron anode and promote the development of aqueous iron-ion batteries.

A CaI2-Based Electrolyte Enabled by Borate Ester Anion Receptors for Reversible Ca-Organic and Ca-Se Batteries.

Passivating solid electrolyte interphases (SEIs) in Ca metal anodes constitute a long-standing challenge, as they block Ca2+ transport and inhibit reversible Ca deposition/stripping. Current solutions focus primarily on boron/aluminum-based electrolytes to mitigate such interfacial issues by producing Ca2+-conductive species, yet the complex synthetic procedure of these salts restricts the widespread application. Moreover, whether any inorganic phases possess decent Ca2+ conductivity within SEIs remains ambiguous. Herein, we report that a commercially available CaI2-dimethoxyethane electrolyte supports reversible Ca/Ca2+ redox reactions via forming CaI2-involved SEI, inspired by our density functional theory calculations where CaI2 species is predicted to possess the lowest Ca2+ diffusion barrier among a range of inorganic phases. We further materialize this finding by introducing a serial of borate ester anion receptors, resulting in the formation of CaI2/borides hybrid SEIs with an enhanced Ca2+ conductivity. Consequently, the resultant electrolytes realize a 7-fold reduction in deposition/stripping overpotential compared to anion receptor-free one, allowing for the construction of reversible Ca-metal full cells with high-capacity selenium and organic cathodes.

A CaI2‐Based Electrolyte Enabled by Borate Ester Anion Receptors for Reversible Ca−Organic and Ca−Se Batteries

AbstractPassivating solid electrolyte interphases (SEIs) in Ca metal anodes constitute a long‐standing challenge, as they block Ca2+ transport and inhibit reversible Ca deposition/stripping. Current solutions focus primarily on boron/aluminum‐based electrolytes to mitigate such interfacial issues by producing Ca2+‐conductive species, yet the complex synthetic procedure of these salts restricts the widespread application. Moreover, whether any inorganic phases possess decent Ca2+ conductivity within SEIs remains ambiguous. Herein, we report that a commercially available CaI2‐dimethoxyethane electrolyte supports reversible Ca/Ca2+ redox reactions via forming CaI2‐involved SEI, inspired by our density functional theory calculations where CaI2 species is predicted to possess the lowest Ca2+ diffusion barrier among a range of inorganic phases. We further materialize this finding by introducing a serial of borate ester anion receptors, resulting in the formation of CaI2/borides hybrid SEIs with an enhanced Ca2+ conductivity. Consequently, the resultant electrolytes realize a 7‐fold reduction in deposition/stripping overpotential compared to anion receptor‐free one, allowing for the construction of reversible Ca‐metal full cells with high‐capacity selenium and organic cathodes.

Toward waterproof magnesium metal anodes by uncovering water-induced passivation and drawing water-tolerant interphases.

Magnesium (Mg) metal is a promising anode candidate for high-energy and cost-effective multivalent metal batteries, but suffers from severe surface passivation in conventional electrolytes, especially aqueous solutions. Here, we uncover that MgH2, in addition to the well-known MgO and Mg(OH)2, can be formed during the passivation of Mg by water. The formation mechanism and spatial distribution of MgH2, and its detrimental effect on interfacial dynamics and stability of Mg anode are revealed by comprehensive experimental and theoretical investigations. Furthermore, a graphite-based hydrophobic and Mg2+-permeable water-tolerant interphase is drawn using a pencil on the surface of Mg anodes, allowing them to cycle stably in symmetric (> 900 h) and full cells (> 500 cycles) even after contact with water. The mechanistic understanding of MgH2-involved Mg passivation and the design of pencil-drawn waterproof Mg anodes may inspire the further development of Mg metal batteries with high water resistance.

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.