Artificial Solid Electrolyte Interphase Layer Research Articles

Self-assembled polysilane artificial solid electrolyte interphase layer towards highly reversible zinc electrochemistry

Commercial applications of aqueous Zn batteries primarily encounter challenges related to surface corrosion and dendrite formation. In this study, a hydrophobic polysilane layer functionalized with −CF3 groups (CF3-PSiOX) is tailored for Zn anode through a two-step process involving self-assembly and condensation. The CF3-PSiOX layer functions as a protective barrier, effectively isolating water and inhibiting corrosion. Moreover, the primary interactions between −CF3 and Zn2+ guides the diffusion and deposition processes of Zn2+ while optimizing the de-solvation process, ultimately resulting in dendrite inhibition. Hence, cells with CF3-PSiOX layer boasts a high Coulombic efficiency (∼99.8 % after 1500 cycles), a long lifespan (over 2400 h), and optimized capacity retention (73.3 % over 1000 cycles). The self-assembled polysilane layer with customizable groups offers a novel approach for tuning the interface properties of Zn anodes and establishes a general principle for interface adjustment applicable to alternative metallic electrodes.

Biomass-derived polymer as a flexible “zincophilic–hydrophobic” solid electrolyte interphase layer to enable practical Zn metal anodes

Aqueous zinc ion batteries (AZIBs) face significant challenges stemming from Zn dendrite growth and water-contact attack, primarily due to the lack of a well-designed solid electrolyte interphase (SEI) to safeguard the Zn anode. Herein, we report a bio-mass derived polymer of chitin on Zn anode (Zn@chitin) as a novel and robust artificial SEI layer to boost the Zn anode rechargeability. The polymeric chitin SEI layer features both zincophilic and hydrophobic characteristics to target the suppressed dendritic Zn formation as well as the water-induced side reactions, thus harvesting a dendrite-free and corrosion-resistant Zn anode. More importantly, this polymeric interphase layer is strong and flexible accommodating the volume changes during repeated cycling. Based on these benefits, the Zn@chitin anode demonstrates prolonged cycling performance surpassing 1300 h under an ultra-large current density of 20 mA cm−2, and a long cycle life of 680 h with a record-high zinc utilization rate of 80 %. Besides, the assembled Zn@chitin/V2O5 full batteries reveal excellent capacity retention and rate performance under practical conditions, proving the reliability of our proposed strategy for industrial AZIBs. Our research offers valuable insights for constructing high-performance AZIBs, and simultaneously realizes the high-efficient use of cheap biomass from a “waste-to-wealth” concept.

Organic Anodes with Nearly 100% Initial Coulombic Efficiency Enabled by Wet‐Chemically Constructed Artificial Solid‐Electrolyte Interphase Film toward High‐Energy‐Density Organic Full Batteries

AbstractLithium‐ion batteries (LIBs) built on inorganic anodes have achieved great commercial success. By contrast, the practical application of organic anode materials encounters key bottlenecks including electronic insulation, high solubility, and poor initial coulombic efficiency (ICE). Among them, improving ICEs (normally 30–60%) faces enormous challenges in both theory and technology, and there has been no substantial breakthrough yet. Herein, a wet chemical pretreatment technology to increase the ICE of maleic acid (MA)‐based anodes from 43.2% to nearly 100% is proposed for the first time, and this strategy demonstrates universal applicability. Typically, the wet chemical pretreatment involves reacting with lithium‐biphenyl to form LixMA intermediates (x = 4–6) and further forming a compact artificial solid‐electrolyte interphase (SEI) film through the spontaneous reaction between active LixMA and battery organic electrolytes. This wet chemically‐constructed artificial SEI layer can almost completely suppress lithium loss in the initial cycle of the MA electrode and significantly boost the actual output energy density, rate capability, and cycling durability of MA anode‐based full batteries. Significantly, the study further demonstrated that a series of organic anode materials with high ICEs can be achieved through similar wet chemical pretreatment. This work will open up the true application of high‐ICE organic anodes in LIBs.

Li3N/SiO2 modified 3D collectors to extend the cycle life of lithium anode

Despite the many benefits of lithium-metal anodes in next-generation lithium-metal batteries, they are limited by their infinite volume expansion and lithium dendrite growth. In this study, we propose a novel method for producing stable lithium-metal anodes by first coating a Cu current collector with a thin insulating silica layer, then laser etching to create holes where lithium deposition can take place. Additionally, an artificial solid electrolyte interphase layer of Li3N, which is generated in situ on the deposited lithium metal surface can reduced electrolyte consumption and promote uniform lithium deposition, and the confined space within the holes prevent dendrite formation. The above design realizes the use of limited lithium and improves the utilization of lithium metal while increasing the safety of the cells. The 3D Cu supported Li anode exhibited stable average coulombic efficiency of 99.8 % for 300 cycles at a current density of 1 Ma cm−2. Specifically, full cells made of such a 3D Cu anode coupled with a LiFePO4 cathode exhibited a capacity of 125 mA h g−1 after 250 cycles (low N/P capacity ratio of 2.38), providing a dendrite-free lithium metal anode.

A Triply-Periodic-Minimal-Surface Structured Interphase based on Fluorinated Polymers Strengthening High-energy Lithium Metal Batteries.

The challenge of constructing a mechanically robust yet lightweight artificial solid-electrolyte interphase layer on lithium (Li) anodes highlights a trade-off between high battery safety and high energy density. Inspired by the intricate microstructure of the white sea urchin, we first develop a polyvinyl fluoride-hexafluoropropylene (PVDF-HFP) interfacial layer with a triple periodic minimal surface structure (TPMS) that could offer maximal modulus with minimal weight. This design endows high mechanical strength to an ordered porous structure, effectively reduces local current density, polarization, and internal resistance, and stabilizes the anode interface. At a low N/P ratio of ~3, using LiFePO4 as the cathode, Li anodes protected by TPMS-structured PVDF-HFP achieve an extremely low capacity-fading-rate of approximately 0.002 % per cycle over 200 cycles at 1 C, with an average discharge capacity of 142 mAh g-1. Meanwhile, the TPMS porous structure saves 50 wt % of the interfacial layer mass, thereby enhancing the energy density of the battery. The TPMS structure is conducive to large-scale additive manufacturing, which will provide a reference for the future development of lightweight, high-energy-density secondary batteries.

Engineering a lithium silicate-based artificial solid electrolyte interphase for enhanced rechargeable lithium metal batteries

The main motivation for replacing lithium-ion batteries with lithium metal batteries is to achieve a higher energy density by using the metallic lithium anode. One of the major challenges with rechargeable lithium metal batteries is the formation of lithium dendrites and dead lithium during repeated cycling. Another challenge is the formation of the unstable solid electrolyte interphase (SEI) on the surface of the lithium metal electrode, which can reduce battery efficiency and cycle life. In the present work, two different lithium silicates (Li2Si2O5 and Li2SiO3) are successfully synthesized and implemented as an artificial SEI layer via a simple dry coating method. The lithium silicate coating acts as a protective barrier that prevents direct contact between the lithium metal and the electrolyte, which can cause undesirable side reactions and reduce the efficiency and lifetime of the battery. The lithium silicate artificial SEI layer improves the stability of lithium metal batteries by reducing unwanted surface reactions, optimizing ion transport kinetics, and protecting the lithium metal anode from mechanical deformation and unstable SEI formation during extended cycling. This laminated lithium anode structure can be an effective design for the future development of rechargeable lithium metal batteries.

Enabling Uniform and Stable Lithium-Ion Diffusion at the Ultrathin Artificial Solid-Electrolyte Interface in Siloxene Anodes.

Constructing a stable and robust solid electrolyte interphase (SEI) has a decisive influence on the charge/discharge kinetics of lithium-ion batteries (LIBs), especially for silicon-based anodes which generate repeated destruction and regeneration of unstable SEI films. Herein, a facile way is proposed to fabricate an artificial SEI layer composed of lithiophilic chitosan on the surface of two-dimensional siloxene, which has aroused wide attention as an advanced anode for LIBs due to its special characteristics. The optimized chitosan-modified siloxene anode exhibits an excellent reversible cyclic stability of about 672.6 mAh g-1 at a current density of 1000mA g-1 after 200 cycles and 139.9 mAh g-1 at 6000mA g-1 for 1200 cycles. Further investigation shows that a stable and LiF-rich SEI film is formed and can effectively adhere to the surface during cycling, redistribute lithium-ion flux, and enable a relatively homogenous lithium-ion diffusion. This work provides constructive guidance for interface engineering strategy of nano-structured silicon anodes.

Lithium-Ion Charged Polymer Channels Flattening Lithium Metal Anode

HighlightsThe LiNO3-implanted electroactive β phase polyvinylidene fluoride-co-hexafluoropropylene was built as an artificial solid electrolyte interphase layer for dendrite suppression.The electronegatively charged polymer layer can capture Li ion on its surface to form Li-ion charged channels and recompense the ionic flux of electrolytes via continuous supply of Li ion.The modified Li anode achieved a long cycle life over 2000 h under ultrahigh Li utilization of 50% in symmetric cell and worked in full cell for 100 cycles at harsh condition of extremely low N/P of 0.83.

In situ construction of robust artificial solid-electrolyte interphase layer on lithium-metal anode by a facile one-step solution route

Development of high energy density lithium-metal batteries (LMBs) is markedly hindered by the interfacial instability on lithium-metal anode side. Solid-electrolyte interphase (SEI) is a fundamental factor to regulate dendrite growth and enhance the stability of lithium-metal anodes. Here, trithiocyanuric acid, a triazine derivative with sulfhydryl groups, is used as an efficient promoter to favor the construction of a robust artificial SEI layer on the lithium metal surface, which greatly benefits the stability and efficiency of LMBs. With the assistance of trithiocyanuric acid facilely introduced on the Li surface via a one-step solution route, a highly uniform artificial SEI layer rich in Li2S and Li3N is formed, which efficiently facilitates uniform lithium deposition and suppresses lithium dendrite growth. Remarkably, the Li|Li cell displays stable lithium plating/stripping cycling over 800 h at 0.5 mA cm−2, 1 mAh cm−2, and the Li|LFP cells exhibit prolonged lifespan over 700 cycles at 3 C and superior rate performance from 2 to 20 C. This work provides a facile design strategy for constructing a superb artificial SEI layer for high-performance LMBs.

Na-Sn Alloy Regulated Protective Coating Layer Enables the Long Life Dendrite-Free Sodium Metal Batteries

Sodium metal anodes are highlighted as the most potential candidates for next-generation batteries due to their high theoretical capacity (1166 mAh/g), low electrochemical potential (-2.71 V vs standard hydrogen electrode), and cheaper material cost. However, practical application of sodium metal batteries is limited due to the uneven solid electrolyte interphase layer and insignificant coulombic efficiency. Designing a protective coating layer as an artificial solid electrolyte interphase layer on a sodium metal anode is one of the main approaches to maintaining the homogenous deposition and long-term stability during the process of electrochemical plating/stripping. Herein, a protective layer of (Na-Sn) alloy and Na-Cl insulator was formed by establishing the spontaneous self-alloying reaction. Most importantly, the proposed Na-Sn metal alloy layer has high ionic conductivity, stable chemical/electrochemical interphase, and robustness to enhance the homogenous Na ion deposition and prevent the uncontrollable sodium dendrites. Based on these effects, using the Na-Sn alloy symmetric cell exhibits the stable electrochemical performance (500 h at 2 mA/cm2 & 2 mAh areal capacity). The Full cell was assembled using the Na3V2(PO4)3 cathode and Na-Sn alloy over sodium metal anode in diglyme electrolyte, showing excellent cycle stability up to 100 cycles at 1 C rate and discharge capacity of 168 mAh/g at 0.1 C rate. This work presents a new technique to produce a uniform Na ion deposition and safe dendrites-free sodium metal batteries (SMBs).

Artificial SEI Layer Combined with Single-Ion Polymer Electrolytes to Prevent Dendrite Growth in Lithium Metal Batteries

Li-metal batteries have the potential to become the next generation of batteries since they can provide an increased energy density vs. Li-ion batteries. However, the safety issue caused by the inhomogeneous Li deposition and Li dendrite growth greatly limits their commercial application. Several methods have been proposed to address this issue. On the one hand, when Li ions are released from one electrode and consumed at the other electrode, it causes a salt concentration gradient. Besides, the electrical migration of anions in the opposite direction aggravates the concentration of gradient since anions do not react at the electrodes. Fast dendritic growth then occurs when the current is high enough to fully deplete the Li+ ion at the anode during charge. Thus, suppressing concentration gradient by immobilizing the anions would in principle solve the fast dendritic growth issue. On the other hand, the Solid Electrolyte Interphase (SEI) plays a crucial role in the operation of Li metal batteries since it prevents further reduction and continuous electrolyte reaction. SEI derives from the passivation layer formed onto the surface of Li metal under dry air during lithium foil extrusion and then evolves further in contact with the electrolytes and during subsequent electrochemical Li stripping/plating. The SEI is inhomogeneous and since it contains lower resistance pathways for Li+ transport, it favors inhomogeneous deposition at any current. Thus, SEI engineering, in order to favor the homogeneity of current density and enhanced mechanical properties to confine lithium could, in principle, improve the performance of Li metal batteries.Thus, we studied the use of single-ion conducting polymers with high cationic transference numbers (tLi+ close to 1) as artificial SEIs (art-SEIs) since they include immobile anions and thus prevent Li+ depletion during charge and, at the same time, improve lithium metal confinement and the homogeneity of current density. Our results show much improved homogeneity of Li deposition and cycling stability after single-ion art-SEI coating using an ether-based liquid electrolyte combined with a separator. Nevertheless, it could not enable long-term cycling as the separator does not enable homogeneous pressure and current density onto the lithium anode. Thus, the use of a single-ion conducting solid polymer electrolyte was combined with a single-ion conducting art-SEI (as illustrated in Figure 1). This strategy allows the suppression of salt concentration gradients, inhomogeneous pressure and current density, thus enables homogeneous Li deposition and long-term cycling of Li metal anode. Figure 1

Robust and Fast‐Ion Conducting Interphase Empowering SiOx Anode Toward High Energy Lithium–Ion Batteries

AbstractSilicon suboxides (SiOx) materials are highly desirable as anode for high energy Li‐ion batteries due to their much higher specific capacity than conventional graphite anode. However, the low initial Coulombic efficiency (ICE) and inadequate capacity retention of SiOx anode arising from its immense volume variation during repeated lithiation/delithiation process greatly hinder its practical applications. To address these drawbacks of SiOx, by a simple calcination method, a robust and fast‐ion conducting interphase enriched of LiF, Li2C2O4, LiBO2, and Li2B4O7 is rationally pre‐constructed With the assistance of this pre‐constructed artificial protective layer, the formed solid‐electrolyte interphase (SEI) layer possesses high Young's modulus and fast Li+ conducting, and thus can accommodate the plastic deformation of SiOx anode, alleviate the parasitic reactions, and maintain the electrode integrity upon cycling. Thus, the modified SiOx (M‐SiOx) anode exhibits higher ICE, better capacity retention and superior rate capability. More encouragingly, full cells pairing the M‐SiOx anode with LiNi0.8Mn0.1Co0.1O2 cathode show a high capacity retention of 80.6% for 200 cycles. This paper reveals the importance of pre‐constructing an artificial SEI layer and regulating interfacial chemistry in improving the performance of SiOx‐based anodes, which is a milestone work for boosting the large scale application of SiOx‐based anodes.

Fluorinated Artificial Solid-Electrolyte-Interphase Layer for Long-Life Sodium Metal Batteries.

Sodium metal batteries have garnered significant attention due to their high theoretical specific capacity, cost effectiveness, and abundant availability. However, the propensity for dendritic sodium formation, stemming from the highly reactive nature of the sodium metal surface, poses safety concerns, and the uncontrollable formation of the solid-electrolyte interphase (SEI) leads to large cell impedance and battery failures. In this study, we present a novel approach where we have successfully developed a stable fluorinated artificial SEI layer on the sodium metal surface by employing various weight percentages of tin fluoride in a dimethyl carbonate solution, utilizing a convenient, cost-effective, and single-step method. The resulting fluoride-rich protective layer effectively stabilized the Na metal surfaces and significantly enhanced cycling stability. The engineered artificial SEI layer demonstrated an enhanced lifetime of Na metal symmetric cells of over 3.5 times, over 700 h at the current density of 0.25 mA/cm2, in cycling performance compared to the untreated sodium, which is attributed to the suppression of dendrite formation and the reduction of undesired SEI formation during high-current cycling.

Covalent Organic Framework Fiber-Constructed Artificial Solid Electrolyte Interphase Layer: Facilitated Uniform Deposition of Li+ and Encapsulated Li Dendrite.

Due to ultrahigh theoretical capacity and ultralow redox poteneial, lithium metal is considered as a promising anode material. However, uneven lithium deposition, uncontrollable lithium dendrite formation, and fragile solid electrolyte interphase (SEI) lead to low lithium utilization, rapid capacity decay, and poor cycle performance. Herein, a robust artificial SEI film by coating the lithium surface with fibrous covalent organic framework (Fib-COF) was constructed, which effectively prevented dendrite penetration and battery short-circuits. Experimental results demonstrated that the Fib-COF-decorated batteries showcased higher Coulombic efficiency (CE), extended cycling stability, and superior electrolyte compatibility. The strong affinity of the carbonyl group in Fib-COF towards Li+ contributes to facilitating the Li+ uniform transfer and nucleation. In situ optical microscopy dynamically revealed the formation process of dendrite-free interphase under the function of Fib-COF layer. As a result, the modified Li anode demonstrated remarkable cycle stability for more than 650 h at 20 mA cm-2 and 5 mAh cm-2 in ether-based electrolyte and 1000 h at 0.5 mA cm-2 and 0.5 mAh cm-2 in carbonate-based electrolyte. The dendrite-free Fib-COF@Li electrodes endowed higher specific capacities of 650 mAh g-1 for Fib-COF@Li|S full cell after 250 cycles and 120 mAh g-1 for Fib-COF @Li|LiFePO4 full cells after 300 cycles.

Click Chemistry in Lithium-Metal Batteries.

Lithium-metal batteries (LMBs) are considered the "holy grail" of the next-generation energy storage systems, and solid-state electrolytes (SSEs) are a kind of critical component assembled in LMBs. However, as one of the most important branches of SSEs, polymer-based electrolytes (PEs) possess several native drawbacks including insufficient ionic conductivity and so on. Click chemistry is a simple, efficient, regioselective, and stereoselective synthesis method, which can be used not only for preparing PEs with outstanding physical and chemical performances, but also for optimizing the stability of solid electrolyte interphase (SEI) layer and elevate the cycling properties of LMBs effectively. Here it is primarily focused on evaluating the merits of click chemistry, summarizing its existing challenges and outlining its increasing role for the designing and fabrication of advanced PEs. The fundamental requirements for reconstructing artificial SEI layer through click chemistry are also summarized, with the aim to offer a thorough comprehension and provide a strategic guidance for exploring the potentials of click chemistry in the field of LMBs.

Spatial Confinement of Li Metal in Hollow Microcapsule Hosts Enabled by Heteroatom-Driven Inward Growth

In recent years, the demand for advanced batteries with high energy densities has increased significantly, along with the growing demand for electric vehicles. Li metal has garnered considerable research attention as a promising anode material because of its high theoretical specific capacity (3860 mAh g−1) and low electrochemical equilibrium potential (−3.040 V vs. standard hydrogen electrode). However, Li metal batteries still have several hurdles in their practical application because Li metal anodes experience infinite volume expansion, which induces continuous rupture and formation of solid-electrolyte interphase (SEI) layers. This leads to electrolyte consumption and corrosion of Li metal, resulting in a low Coulombic efficiency and poor cycling performance. In addition, the uncontrollable dendrite growth of Li metal may cause early battery failure and safety issues. To address these problems, extensive research efforts have been made, including artificial SEI layers, optimized electrolyte formula, and rational design of three-dimensional (3D) host materials.Among the various 3D host materials under development, carbon-based materials with hollow structures have been investigated extensively because of their attractive features. The enlarged void space (cavity) of the hollow hosts can accommodate a significant amount of Li deposits, while inhibiting volume changes during plating–stripping cycles. In addition, hollow carbon possesses much lower density than metal-based materials, thereby increasing the specific capacity and energy density. However, the lithiophobic nature of carbon combined with its high resistance to Li+ transport through nanopores on the walls significantly hinders the formation of Li deposits inside the cavity. Li may nucleate on the outer surface of the carbon particles in a nonuniform manner, thereby causing the growth of Li dendrites and electrochemically inactive Li deposits.In this study, we synthesize metal-organic framework-derived carbon microcapsules with heteroatom clusters (Zn and Ag) on the capsule walls and demonstrate that Ag-assisted nucleation of Li metal alters the outward-to-inward growth in the microcapsule host. The cavity inside the microcapsule host, which was generated by etching with tannic acid, provides large void spaces for Li metal storage. Atomic Ag clusters decorated by a galvanic displacement reaction serve as preferential nucleation sites with a reduced energy barrier and promote the inward growth of Li metal in the cavity, while suppressing nonuniform Li plating on the outer surface. Through combined electrochemical, microstructural, and simulation studies, we verify the beneficial role of Ag-assisted Li nucleation in facilitating inward growth inside the cavity of the microcapsule host, resulting in enhanced electrochemical performance. This study provides new insights into the design of reversible host materials for practical Li-metal batteries.

Polydopamine layer-coated porous Ni foam host for Li metal batteries under lean electrolytic cell operations

Li metal batteries (LMBs) face challenges such as volume change, dendrite growth, electrolyte depletion, and safety concerns. To address these issues, employing three-dimensional (3D) porous substrates and artificial solid electrolyte interphase (SEI) layers has been proposed for uniform Li ion distribution and interfacial stability. Here, we present a dendrite-free Li metal anode for LMBs operating under lean electrolytic conditions. This is achieved by synergistically combining oxidized 3D Ni foam as a conductive substrate and polydopamine (PDA) coating as an artificial SEI layer. The oxidized 3D Ni foam provides abundant lithiophilic sites with a large surface area for Li-ion deposition, effectively mitigating volume expansion due to its high elastic modulus. The PDA artificial SEI layer acts as a protective barrier, enhancing electrolyte wettability and preventing direct contact with Li metal surface. The PDA-coated oxidized 3D Ni foam demonstrates stabilized operation in full cell even with a small amount of electrolyte, achieving a Coulombic efficiency of approximately 99 % over 150 cycles and an exceptionally low voltage hysteresis (∼10 mV) for over 400 h. Our approach utilizing the highly conductive 3D foam substrate and the passivating PDA SEI layer enables outstanding electrochemical performance, opening avenues for future research on commercially viable LMBs.

Construction of desolvated ionic COF artificial SEI layer stabilized Zn metal anode by in-situ electrophoretic deposition

Aqueous zinc-ion batteries (AZIBs) have attracted tremendous attention due to their cost-effectiveness, environmental-friendliness, and intrinsic safety. However, the spontaneous surface corrosion and uncontrolled dendrite growth of AZIBs severely restrict its practical application. Herein, we develop an artificial solid electrolyte interphase (SEI) with ionic covalent-organic-framework (iCOF) nanosheets for Zn anode protection. The iCOF nanosheets form an artificial SEI layer with porous and abundant zincophilic sites through in-situ electrophoretic deposition (ED) technique, which allows for efficient mass and charge transfer. The iCOF-ED SEI layer not only facilitates a uniform Zn2+ flux but regulates the Zn2+ solvation shell, resulting in a stable and homogeneous Zn2+ deposition. This novel iCOF-ED SEI layer enables high stability for over 1000 h (with ultralow overpotential ∼ 50 mV) at 1 mA cm−2 in symmetric cells and enhances cycling stability over 1100 cycles (with high average coulombic efficiency of 99.9 %) at 2 A g−1 in half cells. This finding provides a facile and promising route for the scalable production of anodes with artificial SEI, thus promoting the development of high-performance AZIBs.

Achieving multi-dimensional Li+ transport nanochannels via spatial-partitioning in crystalline ionic covalent organic frameworks for highly stable lithium metal anode

The fragile solid electrolyte interphase (SEI) and anisotropic dendrite growth during Li plating/stripping have posed as intractable handicaps to the practical implementation of lithium metal batteries (LMBs). The Li+ uniform distribution and unimpeded transfer play significant roles to enable protuberance-free Li textures. Herein, the highly-crystalline TFSI− ionic-covalent organic framework (I-COF) endowed with designated mixed-dimensional channels was constructed as an artificial SEI layer via anionic post-modification. Benefiting from the desirable spatial-partitioning effect triggered by nanochannels reconfiguration, the I-COF with expanded multi-dimensional Li+ transport channels and scaled-down pore volume could effectively disperse the local concentration gradient of Li+ flux and inhibit growth of Li dendrites. Besides, the coordinated TFSI− anions with a high tLi+ of 0.76 can selectively restrict the delivery and decomposition of homogeneous ions. To understand the interfacial charge transfer mechanisms, the lithophilic properties and the energy barriers for Li+ migration were also calculated. Correspondingly, the I-COF(TI−) modified Li|Li symmetric cell showed superb durability over 5500 h at 4 mA cm−2 with extraordinary overpotential. The Li|S full cell also displayed prolonged lifespan and excellent rate performance. The comprehension of the mixed-dimensional interfacial strategy via spatial-partitioning provides new insights into the fabrication of solid–solid interfaces, which can aid in the improved design and development of advanced lithium-metal batteries (LMBs).

A porous lithium metal anode with an artificial solid electrolyte interface fabricated by a facile process

Lithium metal batteries (LMBs) have been considered a next-generation energy storage system. However, dendrite growth on lithium metal anode has critical issues with poor Coulombic efficiency and safety problems such as short-circuiting. Moreover, the continuous growth of dendrites leads to severe volume expansion of the electrode. To solve these problems, we suggest a lithium metal anode with a porous structure covered by artificial solid electrolyte interphase (SEI) layer. The porous lithium metal anode with the artificial SEI layer is prepared simply by dissolving lithium salt (lithium bis(fluorosulfonyl)imide, LiFSI) from a pellet of the mixture of lithium metal powder and lithium salt. In contrast to planar lithium metal foil, the porous structure decreases areal current density and reduces the possibility to form long dendrites penetrating the separator. Also, the artificial SEI layer with a porous structure induces uniform plating of lithium above and inside the lithium metal anode. As a result, the symmetric cells with the porous lithium metal anode show enhanced cycle life and rate capability compared to the anode prepared with bare lithium metal powder. Furthermore, the full cell assembled with the porous lithium metal anode and NCM811 cathode also shows significantly higher rate capability than the bare lithium metal anode. Our results provide a better understanding for designing a porous lithium metal anode with an inherent SEI layer for high-capacity and high-rate lithium metal batteries.