Artificial Solid Electrolyte Interface Research Articles

Synergistic Long-Term Protection of Inorganic and Polymer Hybrid Coatings for Free-Dendrite Zinc Anodes.

Constructing an artificial solid electrolyte interface protective layer on the surface of the zinc anode is an effective strategy for addressing dendrite growth, passivation, and the hydrogen evolution reaction in aqueous zinc-ion batteries. This study introduces a robust interlayer composed of a polyvinyl butyral matrix decorated with SiO2 particles (PS). Adsorption of water by Si-OH on the surface of SiO2 leads to excellent hydrophilicity and accelerates the desolvation of ions. A highly stable and hydrophilic PS coating enhances ion migration and possesses ultralong protection ability, ensuring uniform ion deposition and a lower nucleation barrier. Anodes protected by the PS coating achieve long-term cycling stability of >4000 h at 2 mA cm-2 in symmetric cells. The assembled PS-Zn//NH4V4O10 full cells exhibit superior electrochemical performance, demonstrating their potential for practical applications in rechargeable zinc batteries.

Surface Science and Engineering for Electrochemical Materials.

ConspectusIn electrochemical energy storage systems, the reversible storage capacity of battery materials often degrades due to parasitic reactions at the electrode-electrolyte interface, transitional metal dissolution, and metallic dendrite growth at the surface. Surface engineering techniques offer the opportunity to modify the composition and structure of a surface, thereby enabling control over chemical reactions occurring at the surface and manipulating chemical interactions at the solid-solid or solid-liquid interface. These modifications can help stabilize the surface of electrode materials and prevent unwanted reactions with electrolytes without changing the original properties of the bulk structure. This allows for achieving full theoretical capacity and maximizing battery material capacity retention with minimal overpotentials. In the past decade, our teams have been working on developing a variety of surface engineering techniques. These include applying atomic and molecular layer deposition (ALD and MLD), templating, doping, and coating via wet-chemical processes to stabilize the surfaces of electrode materials. The aim is to mitigate parasitic side-reactions without impeding charge transfer kinetics, suppress dendrite growth, and ultimately improve the electrode performance.This Account summarizes the research conducted in our research laboratory with an aim to improve battery cycling durability and efficiency by modifying electrode surfaces. We have employed techniques such as ALD, MLD, templating, and wet-chemical processes to illustrate how the stabilized surface improves the performance of lithium-ion (Li-ion), solid-state electrolytes and magnesium-metal (Mg-metal) batteries. For instance, by applying ultrathin layers of inorganic (e.g., Al2O3) or organic-inorganic coatings (e.g., alucone, lithicone, and polyamides) to the surface of LiNixMnyCozO2 (x + y + z = 1, NMC) and silicon (Si) electrodes─usually just a few angstroms or nanometers thick─we have observed notable improvements in cycling efficiency and durability. When using ultrathick electrodes, the traditional electrode fabrication has a problem with high tortuosity, which hinders both rate capability and long-term cycling. To solve this issue, three-dimensional templates have been employed to reduce electrode tortuosity, enabling high-rate performance and long-term cycling. In the case of Mg-metal batteries, the buildup of an insulating MgO layer due to side reactions with electrolytes blocks Mg2+ ion transport, which can ultimately cause the battery to fail. To address this issue, we have developed an artificial solid-electrolyte interface using cyclized polyacrylonitrile and magnesium trifluoromethanesulfonate. This interface prevents the reduction of the carbonate electrolyte while allowing Mg2+ diffusion, ultimately boosting overall cell performance.This Account also discusses the significance of choosing suitable materials and effective surface engineering methods with the objective of enhancing surface properties while preserving the bulk properties of the electrodes. It is believed that surface modification and engineering can not only significantly improve the electrochemical performance of existing battery materials but also facilitate the development of new battery materials that were previously incompatible with current electrolytes. By highlighting these aspects, this Account underscores the transformative potential of surface modification and engineering in battery technology, paving the way for future innovations in energy storage solutions.

Constructing a Li–Zn lithiophilic layer by a scalable method of magnetron sputtering for a high-quality Li–B alloy anode

Lithium metal anodes offer high theoretical capacity and low redox potential but face challenges like dendritic growth, fragile solid electrolyte interface (SEI), "dead lithium" formation, and volume expansion. Composite anodes or artificial SEIs can address these issues, but often suffer from poor lithiophilicity and mass burdens. This study presents a Li–Zn–B alloy anode combining a Li–Zn lithiophilic layer with a bulk Li–B alloy. The Li–Zn lithiophilic layer, formed by magnetron sputtering of Zinc oxide (ZnO), improves surface lithiophilicity. Symmetrical cells with this alloy cycled stably for 1300 (1 mA cm−2, 1 mAh cm−2) and 550 h (2 mA cm−2, 2 mAh cm−2) with minimal overpotentials. The LiBZn||NCM811 full cell showed a specific discharge capacity of 130.8 mAh/g and stable Coulombic efficiency of 98.9 % after 300 cycles.

Rolling strategy for highly efficient preparation of phosphating interface enabled the stable lithium anode

Lithium metal anode has an ultra-high theoretical specific capacity and the lowest reduction potential, regarded as the next-generation anode material for high-energy-density batteries. However, the lithium metal anode suffers from the severe side reaction and Li dendrite growth caused by the inhomogeneous deposition of Li+ on the anode during the electrochemical cycling. Herein, a strategy is proposed to design an artificial solid electrolyte interface (SEI) by rolling with the organic phosphating lubricant. The obtained phosphating interface with high surface energy and surface Young’s modulus significantly induces the dense deposition of Li+ and results in a stable cycling. The phosphating interface enables the symmetric cells to cycle stably for 750 h at 1 mA cm−2 with 1 mA h cm−2 and for 450 h at 3 mA cm−2 with 3 mA h cm−2 using ester-based electrolyte. The full cell with high single-side mass loading (10 mg cm−2) of LiCoO2 achieves a capacity retention rate of 77.7 % after 165 cycles at 1 C and 75.6 % after 120 cycles at 2 C. This work paves a path to construct a green fluorine-free interface and provide a large-scale modification for practical lithium strips.

Diffusion of Carbon Quantum Dots on Lithium Liquid Metal for Artificial SEI

AbstractThe unstable solid electrolyte interface (SEI) formed on the surface of Li metal can induce dendrite growth, resulting in capacity fading, battery short circuit, and other problems, thus hindering the practical application of Li metal battery. In order to obtain stable and effective SEI, it is an effective strategy to construct an ideal artificial SEI (ASEI) by regulating the composition and structure of the interface. Among the inorganic materials used in the construction of ASEI, carbon quantum dots (CQDs) stand out as promising material due to their small size and abundant active sites. Herein, benefiting from the fluidity, surface smoothness, and high reactivity of liquid metal, combined with the use of N‐doped CQDs as dispersing particles, a surface modification method to achieve uniform dispersion of particles within the liquid metal is proposed. This technique offers a low‐cost solution for achieving uniform dispersion of little quantities of N‐doped CQDs (single dose < 0.1 mg cm−2) while ensuring enhanced interface adhesion to realize the construction of dense, strong and uniform ASEI. The corresponding symmetrical cells show lower voltage polarization and outstanding cycling stability than the bare Li electrode.

Surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface for stable lithium anodes

Lithium (Li) metal has become a research hotspot for anodes materials due to its ultra-high theoretical capacity and the lowest redox potential. However, the practical application of Li metal batteries is hampered by the formation of uncontrollable Li dendrites and the irreversible structural changes during long-term charge/discharge processes. Developing stable Li metal anode with uniform Li deposition is highly desirable. Herein, surface fluorination of nickel nanowires enabling LiF-rich nanoscale solid electrolyte interface was demonstrated for stable Li anodes. Free-standing three-dimensional (3D) nickel nanowires (NiNWs) current collector decorated with lithiophilic NiF2 nanosheets (NiNWs@NiF2) was constructed via a simple and scalable fluorination strategy. Theoretical and experimental analysis confirmed that the lithiophilic surface of NiF2 nanosheets could reduce the Li nucleation barrier, facilitating uniform Li ion deposition. The 3D conductive NiNWs network enabled fast electron transfer and mitigated volume changes during cycling. Additionally, a LiF-rich nanoscale solid electrolyte interface (SEI) layer formed between Li and the electrolyte significantly improved the interfacial stability. As a result, the as-assembled Li-NiNWs@NiF2 symmetrical cell provided a superior electrochemical performance, maintaining stability for 2500 h at 1.0 mA cm−2 and 900 h at 5.0 mA cm−2. Furthermore, the assembled Li-NiNWs@NiF2|| LiFePO4 (LFP) full cell demonstrated exceptional capacity retention of 93.9 % after 2000 cycles at a rate of 5C. Overall, the unique structure of NiNWs@NiF2 not only offers a straightforward method for designing a 3D lithiophilic host, but also provides the concept of interfacial engineering through the in-situ construction of an artificial LiF-rich nanoscale SEI layer.

Synergistic effect of LixSi/Li3N artificial interface and 3D framework for enabling Dendrite-free, long-life lithium metal anodes

Lithium metal is highly favored as an ideal anode material in future high-capacity lithium batteries due to its appealing properties. Nevertheless, the implementation of lithium metal batteries (LMBs) is severely plagued by challenges such as instable solid electrolyte interface (SEI), uncontrolled growth of dendrite, and severe volume expansion. Herein, to address the aforementioned issues, an artificial SEI layer is fabricated, which is comprised of LixSi alloy and Li3N. The in-situ generated LixSi/Li3N interface is formed on the carbon fiber (denoted as CF/LixSi/Li3N) through a spontaneous reaction between molten Li and Si3N4. Density functional theory (DFT) calculations reveal that LixSi alloy has low ion diffusion energy barrier, which facilitates the low nucleation overpotential of Li+ and enables homogeneous lithium deposition. Li3N can further promote the rapid Li+ transport due to the excellent Li+ conductivity. In addition, the reserved 3D space effectively mitigates the volume change along cycling procedure. Owing to the synergistic effect of the LixSi/Li3N protective layer and the 3D structure, the composite anode shows higher cycling stability with a lifetime of more than 3000 cycles at 1 mA cm−2. Furthermore, matched with commercial LiFePO4 (LFP) and LiNi5Co2Mn3O2 (NCM523) cathodes, the full cells also exhibit impressive electrochemical properties. This work introduces an ingenious approach for constructing stable lithium metal anodes and effective lithium metal batteries.

In-Situ Ultrafast Construction of Zinc Tungstate Interface Layer for Highly Reversible Zinc Anodes.

Constructing artificial solid electrolyte interface on the Zn anode surface is recognized as an appealing method to inhibit zinc dendrites and side reactions, whereas the current techniques are complex and time-consuming. Here, a robust and zincophilic zinc tungstate (ZnWO4) layer has been in situ constructed on the Zn anode surface (denoted as ZWO@Zn) by an ultrafast chemical solution reaction. Comprehensive characterizations and theoretical calculations demonstrate that the ZWO layer can effectively modulate the interfacial electric field distribution and promote the Zn2+ uniform diffusion, thus facilitating the uniform Zn2+ nucleation and suppressing zinc dendrites. Besides, ZWO layer can prevent direct contact between the Zn/water and increase the hydrogen evolution reaction overpotential to eliminate side reactions. Consequently, the in situ constructed ZWO layer facilitates remarkable reversibility in the ZWO@Zn||Ti battery, achieving an impressive Coulombic efficiency of 99.36 % under 1.0 mA cm-2, unprecedented cycling lifespan exceeding 1800 h under 1.0 mA cm-2 in ZWO@Zn||ZWO@Zn battery, and a steady and reliable operation of the overall ZWO@Zn||VS2 battery. The work provides a simple, low cost, and ultrafast pathway to crafting protective layers for driving advancements in aqueous zinc-metal batteries.

In‐Situ Ultrafast Construction of Zinc Tungstate Interface Layer for Highly Reversible Zinc Anodes

AbstractConstructing artificial solid electrolyte interface on the Zn anode surface is recognized as an appealing method to inhibit zinc dendrites and side reactions, whereas the current techniques are complex and time‐consuming. Here, a robust and zincophilic zinc tungstate (ZnWO4) layer has been in situ constructed on the Zn anode surface (denoted as ZWO@Zn) by an ultrafast chemical solution reaction. Comprehensive characterizations and theoretical calculations demonstrate that the ZWO layer can effectively modulate the interfacial electric field distribution and promote the Zn2+ uniform diffusion, thus facilitating the uniform Zn2+ nucleation and suppressing zinc dendrites. Besides, ZWO layer can prevent direct contact between the Zn/water and increase the hydrogen evolution reaction overpotential to eliminate side reactions. Consequently, the in situ constructed ZWO layer facilitates remarkable reversibility in the ZWO@Zn||Ti battery, achieving an impressive Coulombic efficiency of 99.36 % under 1.0 mA cm−2, unprecedented cycling lifespan exceeding 1800 h under 1.0 mA cm−2 in ZWO@Zn||ZWO@Zn battery, and a steady and reliable operation of the overall ZWO@Zn||VS2 battery. The work provides a simple, low cost, and ultrafast pathway to crafting protective layers for driving advancements in aqueous zinc‐metal batteries.

Plasma-enhanced SnO2-x thin films on copper current collector for safer lithium metal batteries

Anode-free lithium batteries are a safer and lighter alternative, because they eliminate the traditional host anode for lithium ions, thereby enhancing energy density and reducing the battery weight. However, challenges like dendritic growth and electrolyte decomposition persist, affecting battery lifespan. Here, we present a scalable technique using plasma enhanced chemical vapor deposition (PECVD) of a tin(IV) precursor to directly deposit an artificial solid electrolyte interface (SEI) on the copper current collector. The obtained SnO2-x coatings, modified by oxygen plasma, exhibited remarkable electrochemical properties. X-ray photoelectron spectroscopy (XPS) is employed to examine the surface composition and impact of plasma treatment, while long-term cycling and electrochemical impedance spectroscopy (EIS) confirm battery durability. Scanning electron microscopy (SEM) and contact angle measurements elucidate coating homogeneity, with lithium nucleation overpotential during first cycle providing further evidence for homogeneity during lithium de-/plating.

Lithium-conducting phosphates as artificial solid-electrolyte interphase on silicon anode for supreme lithium storage

Silicon (Si) anode is an ideal material for next-generation lithium-ion batteries due to its high specific capacity. Unfortunately, the fragmentation and reconstruction of solid electrolyte interface (SEI) film caused by volume expansion during the (de)lithiation is still a problem to be overcome. Constructing a stable SEI film on Si surface through interface engineering is a very effective strategy to improve the electrochemical performance. In this work, we construct lithium-conducting phosphates (Li3PO4, denoted as LPO) as SEI film and SiOx buffer layer on Si surface. The obtained Si@SiOx@LPO anode retains 2015 mAh g−1 after 100 cycles at 0.2 A g−1 with a capacity retention of 73.6%, and 1636 mAh g−1 after 500 cycles at 1 A g−1 with a capacity retention of 81.7%, which is significantly higher than the Si anode under the same conditions, respectively. In addition, in/ex-situ tests demonstrate that Si@SiOx@LPO anode has faster lithium-ion diffusion and structural reversibility. The analysis shows that LPO has higher mechanical strength and provides better ionic conductivity. On the other hand, SiOx buffer layer can not only reduce the volume expansion of Si, but also reduce the energy barrier between Si and LPO interface and increase the electrical conductivity. Therefore, this work provides a novel strategy for boosting electrochemical performance by artificial SEI and surface modification.

Cation-polymerized artificial SEI layer modified Li metal applied in soft-matter polymer electrolyte

Li metal batteries with polymer electrolyte are of great interest for next-generation batteries for high safety and high energy density. However, uneven deposition on the lithium metal surface can greatly affect battery life. Therefore, surface modification on the Li metal become necessary to achieve good performance. Herein, an artificial solid electrolyte interface (SEI) modified lithium metal anode is prepared using cation-polymerization process, as triggered by PF5 generated from CsPF6. As a result, the polarization voltage of Li||Li symmetric battery assembled with artificial SEI-modified Li metal anode was stable with a small over-potential of 25 mV after 3000 h at current density of 1.5 mA cm−2. Electrochemical performance of Li||NCM 622 (LiNi0.6Co0.2Mn0.2O2) full cell with soft-matter polymer electrolyte is significantly improved than bare Li-metal, the capacity retention is 75% after 120 cycles with N/P = 3:1 at a cut-off voltage of 4.3 V. Our work has shed lights on the commercialization of Li metal battery with polymer electrolyte.

Isotropic Structure and Polymer Interface Intensified Lithium-Ion Transmission in Spherical Graphite Tailings/Coke Composite Anode

Spherical graphite tailings (SGT) as the anode electrode for a lithium-ion battery not only improves the utilization value of SGT as solid waste, but also demonstrates the cleaner production of natural flake graphite (NG) compared with artificial graphite. However, SGT anodes present issues regarding rate performance and cycle stability due to the anisotropy structure and the instability of the solid electrolyte interface (SEI). In this work, a composite anode with isotropic structure was prepared by granulation of high-sulfur coal (HSC) and SGT, while an artificial SEI was prepared utilizing polyether amine/polyvinyl pyrrolidone (PEA/PVP) crosslinked polymer. Results showed that the coke from HSC pyrolysis enhanced the isotropy of the composite anode and improved its rate performance. Compared with SGT, the capacity retention rate of the sample (OSGT-50%OHSC) after oxidation - pyrolysis at a high current density of 5.0 A g−1 increased from 7.2% to 25.8%. Additionally, the PEA/PVP artificial SEI strengthened the cycle stability of the anode. After 1000 cycles, the capacity retention rate increased from 22.5% to 70.3%. The artificial SEI effectively avoided direct contact between the anode and the electrolyte, increasing the initial coulombic efficiency from 70.3% to 77.1%.

Dynamic Interfacial Protection via Molecularly Tailored Copolymer for Durable Artificial Solid Electrolyte Interphase in Lithium Metal Batteries

AbstractThe serious dendrite formation and safety hazards associated with side reactions hinder the practical application of lithium metal batteries. A molecular customization strategy based on both physical and chemical properties is reported. A copolymer of acrylamide and hexafluorobutyl acrylate molecules is used as an artificial solid electrolyte interface(ASEI) for lithium metal to achieve dynamic interface protection during cycling. The amide group serves as the rigid unit, while the hexafluorobutyl group serves as the flexible unit, and imparts excellent mechanical properties to the copolymer. Synergistically abundant C─F bonds exhibit excellent water and oxygen resistance and have good electrolyte affinity. The ester and amide groups serve as amphiphilic sites for Li+ and PF6−, regulating the ion flux at the interface and achieving dendrite‐free lithium deposition. During cycling, the organic–inorganic composite SEI dynamically evolves to safeguard the lithium metal, preventing undue electrolyte consumption. The copolymer achieves stable cycling for 1500 and 950 h at 1 and 2 mA cm−2, respectively. It demonstrates excellent performance with LiNi0.8Co0.1Mn0.1O2 and LiFePO4 cathodes. This study introduces a new approach to designing polymers at the molecular level to optimize the physical properties/chemical activity of lithium metal interfaces.

On the Practicability of the Solid‐State Electrochemical Pre‐Sodiation Technique on Hard Carbon Anodes for Sodium‐Ion Batteries

AbstractHard carbon (HC) with low cost and high specific capacity is considered the appropriate anode material for sodium‐ion batteries (SIBs), but the low initial coulombic efficiency (ICE) caused by solid electrolyte interface (SEI) formation and inherent active defects impede its practical battery application. Here, the practicability of solid‐state electrochemical (SSE) pre‐sodiation technique for hard carbon anode is assessed to conquer such challenges. The uniformly pre‐sodiated HC (Pre‐HC) can be fabricated through the SSE reaction between the HC and preloaded sodium metal film without introducing a liquid electrolyte. After being immerged in the electrolyte, a thin artificial SEI with abundant inorganic species is formed on the surface of Pre‐HC due to the spontaneous chemical reaction, and the ICE of HC is improved from 76.0% to 107.9%. Full cell paired with Na3V2(PO4)3 cathode exhibits a high ICE of 94.0% with 70% of energy density augment (from 126.5 to 214.4 Wh kg−1) after anode pre‐sodiation. Pre‐HC anode still retains the pre‐sodiation capacity of 671.1 mAh gNa−1 after being stored in the dry air for 2 h. This work demonstrates the practical applicability of this SSE pre‐sodiation strategy to enhance the energy density of SIBs.

Stabilizing poly(vinylidene fluoride) solid-state electrolytes/lithium metal interface by constructing an ultrathin interface layer to inhibit the electron transfer

Residual N, N-dimethylformamide (DMF) enhances the conductivity of poly(vinylidene fluoride) (PVDF) solid-state polymer electrolytes (SPEs), but adversely impacts the SPEs/Li interface through electron transfer between DMF and Li. Herein, we developed a novel LiOH and LiNH2 (LON) artificial solid electrolyte interface (SEI) layer with limited electronic conductivity to block such electron transfer. Unlike conventional SEI, which are unsuitable for integration with SPEs since their high thickness (1–30 μm) results in high interfacial resistance, the LON layer is ultrathin (∼30 nm), and more importantly, it facilitates the separation of Li ions from Li-DMF bound ions during Li plating, contributing to a notable reduction in interfacial impedance. As a result, the LON protected Li (Li@LON)-based symmetrical cell exhibits an ultra-long cycle life of 2100 h and survives even under 0.6 mAh cm−2 at 25 °C, in stark contrast to the Bare Li-based symmetrical cell, which only maintains stable cycles for 806 h at 0.2 mAh cm−2. Furthermore, the Li@LON//LiNi0.8Co0.1Mn0.1O2 (NCM811) cell stably cycles over 3000 times at 0.5 C and 25 °C, significantly outperforming the Li//NCM811 cell with 880 times. This work paves a novel strategy for stabilizing SPEs-Li interface by constructing an ultrathin artificial SEI with low electronic conductivity.

Artificial LiF-Rich Interface Enabled by In situ Electrochemical Fluorination for Stable Lithium-Metal Batteries.

Lithium (Li)-metal batteries are promising next-generation energy storage systems. One drawback of uncontrollable electrolyte degradation is the ability to form a fragile and nonuniform solid electrolyte interface (SEI). In this study, we propose the use of a fluorinated carbon nanotube (CNT) macrofilm (CMF) on Li metal as a hybrid anode, which can regulate the redox state at the anode/electrolyte interface. Due to the favorable reaction energy between the plated Li and fluorinated CNTs, the metal can be fluorinated directly to a LiF-rich SEI during the charging process, leading to a high Young's modulus (~2.0 GPa) and fast ionic transfer (~2.59×10-7 S cm-1 ). The obtained SEI can guide the homogeneous plating/stripping of Li during electrochemical processes while suppressing dendrite growth. In particular, the hybrid of endowed full cells with substantially enhanced cyclability allows for high capacity retention (~99.3 %) and remarkable rate capacity. This work can extend fluorination technology into a platform to control artificial SEI formation in Li-metal batteries, increasing the stability and long-term performance of the resulting material.

Artificial LiF‐Rich Interface Enabled by In situ Electrochemical Fluorination for Stable Lithium‐Metal Batteries

AbstractLithium (Li)‐metal batteries are promising next‐generation energy storage systems. One drawback of uncontrollable electrolyte degradation is the ability to form a fragile and nonuniform solid electrolyte interface (SEI). In this study, we propose the use of a fluorinated carbon nanotube (CNT) macrofilm (CMF) on Li metal as a hybrid anode, which can regulate the redox state at the anode/electrolyte interface. Due to the favorable reaction energy between the plated Li and fluorinated CNTs, the metal can be fluorinated directly to a LiF‐rich SEI during the charging process, leading to a high Young's modulus (~2.0 GPa) and fast ionic transfer (~2.59×10−7 S cm−1). The obtained SEI can guide the homogeneous plating/stripping of Li during electrochemical processes while suppressing dendrite growth. In particular, the hybrid of endowed full cells with substantially enhanced cyclability allows for high capacity retention (~99.3 %) and remarkable rate capacity. This work can extend fluorination technology into a platform to control artificial SEI formation in Li‐metal batteries, increasing the stability and long‐term performance of the resulting material.

Molybdenum dialkyphosphorodithioate-derived artificial solid-electrolyte interface enabling stable lithium metal anodes

Lithium metal is a promising candidate for next-generation high-energy-density battery systems, but it is hindered by the unstable interface, detrimental side reactions, and uncontrolled dendrite growth. In this paper, a robust organic/inorganic artificial solid-electrolyte interface was constructed based on the mechanochemical reaction between molybdenum dialkyphosphorodithioate (MoDTP) rolling oil and lithium metal under rolling. The interface layer, consisting of organic outer layer (organic polyphosphate, and thiolate) and inorganic inner layer (Li2S, MoS2, Li3PO4, and MoO2), not only inhibits Li dendrite growth effectively due to its excellent mechanical properties (with high Young's modulus of ∼21 GPa), but also enhances Li-ion diffusion with fast ion conductors from the interface. The Li anode rolled by using MoDTP (Li@MoDTP) achieves a stable long-lifespan over 5400 h at 5 mA cm2 and 5 mAh cm2. Meanwhile, the LiFePO4 ||Li@MoDTP full cell also exhibits impressive longevity when pairing with a high single-sided cathode loading of 13 mg cm−2, which lasts over 750 cycles at 1 C rate (1 C = 170 mA g−1). This work sheds lights on producing stable and practical Li metal anodes through mechanical rolling with tailored rolling oils.

Overcoming passivation in rechargeable magnesium batteries: Artificial solid-electrolyte interface for enhanced anode functionality

Rechargeable magnesium batteries (RMBs) have garnered significant attention in the field of energy storage. However, the use of a traditional electrolyte, Mg(TFSI)2/DME, leads to the passivation of the Mg metal anode (MMA), limiting the reversible deposition and dissolution process of Mg2+. Consequently, we propose a feasible method to modify the MMA, resulting in the formation of an artificial solid-electrolyte interface (SEI) coating rich in MgBr2, MgI2 and Sb. This modification leads to substantial improvements in the interfacial kinetics and electrochemical properties of MMA, effectively suppressing the passivation reaction and significantly reducing the overpotential from 2 V to 0.3 V. Upon incorporating CuS/VS4 cathode materials with a 0.15 M SbBr3 modification, the discharge capacity reached 125 and 191 mAh·g−1, respectively (compared to the initial capacity of 30 and 98 mAh·g−1) after 30 cycles. Similarly, with a 0.8 M SbI3 modification, the battery exhibited capacities of 220 and 240 mAh·g−1, respectively. Through a combination of experimental and computational analyses, we confirmed the uniform distribution of Sb, MgBr2 and MgI2 on the MMA surface and a substantial decrease in the diffusion barrier of Mg2+. This study presents a straightforward and efficient method for constructing an artificial SEI coating.