Enhanced Stability of Li Metal Anodes by Synergetic Control of Nucleation and the Solid Electrolyte Interphase

Use of a protective coating on a lithium metal anode (LMA) is an effective approach to enhance its coulombic efficiency and cycling stability. Here, a facile approach to produce uniform silver nanoparticle‐decorated LMA for high‐performance Li metal batteries (LMBs) is reported. This effective treatment can lead to well‐controlled nucleation and the formation of a stable solid electrolyte interphase (SEI). Ag nanoparticles embedded in the surface of Li anodes induce uniform Li plating/stripping morphologies with reduced overpotential. More importantly, cross‐linked lithium fluoride‐rich interphase formed during Ag⁺ reduction enables a highly stable SEI layer. Based on the Ag‐LiF decorated anodes, LMBs with LiNi_1/3Mn_1/3Co_1/3O₂ cathode (≈1.8 mAh cm^?2) can retain >80% capacity over 500 cycles. The similar approach can also be used to treat sodium metal anodes. Excellent stability (80% capacity retention in 10 000 cycles) is obtained for a Na||Na₃V₂(PO₄)₃ full cell using a Na‐Ag‐NaF/Na anode cycled in carbonate electrolyte. These results clearly indicate that synergetic control of the nucleation and SEI is an efficient approach to stabilize rechargeable metal batteries.     

Steel Anti-Corrosion Strategy Enables Long-Cycle Zn Anode

The progress of aqueous zinc batteries (AZBs) is limited by the poor cycling life due to Zn anode instability, including dendrite growth, surface corrosion, and passivation. Inspired by the anti-corrosion strategy of steel industry, a compounding corrosion inhibitor (CCI) is employed as the electrolyte additive for Zn metal anode protection. It is shown that CCI can spontaneously generate a uniform and ≈30 nm thick solid-electrolyte interphase (SEI) layer on Zn anode with a strong adhesion via Zn O bonding. This SEI layer efficiently prohibits water corrosion and guides homogeneous Zn deposition without obvious dendrite formation. This enables reversible Zn deposition and dissolution for over 1100 h under the condition of 1 mA cm⁻² and 1 mAh cm⁻² in symmetric cells. The Zn-MnO₂ full cells with CCI-modified electrolyte deliver an ultralow capacity decay rate (0.013% per cycle) at 0.5 A g⁻¹ over 1000 cycles. Such an innovative strategy paves a low-cost way to achieve AZBs with long lifespan.     

Self-Assembled Lithiophilic Interface with Abundant Nickel-Bis(Dithiolene) Sites Enabling Highly Durable and Dendrite-Free Lithium Metal Batteries

Despite its ultrahigh theoretical capacity and ultralow redox electrochemical potential, the practical application of lithium metal anodes is still hampered by severe dendrite growth and unstable solid electrolyte interphase (SEI). Herein, a self-assembled lithiophilic interface (SALI) for regulating Li electroplating behavior is constructed by introducing a meticulously synthesized Ni-bis(dithiolene)-based molecule (NiS₄-COOH) into a hybrid fluorinated ester-ether electrolyte. The NiS₄-COOH molecules with carboxyl functional groups can spontaneously anchor on the Li metal surface to form a SALI, whose abundant Ni-bis(dithiolene) sites can effectively reduce the initial Li deposition overpotential and guide the subsequent uniform Li electrodeposition. Moreover, due to the interaction between the coordination unsaturated Ni atom and the negatively charged PF₆⁻, the NiS₄-COOH additive can significantly change the ionic coordination environment in the electrolyte, which is greatly conducive to suppressing PF₆⁻ decomposition, optimizing SEI composition and accelerating Li-ion transfer. Consequently, the NiS₄-COOH-modified electrolyte leads to impressive electrochemical performance of Li||LiFePO₄ and Li||LiNi_0.8Co_0.1Mn_0.1O₂ batteries, delivering ultrahigh Coulombic efficiencies, considerable capacity retention, and good rate performance even at high areal active material loadings. This study presents the great potential of SALIs derived from multifunctional metal-organic hybrid electrolyte additives toward high-specific-energy Li metal batteries.     

Interrelation Between External Pressure,SEI Structure,and Electrodeposit Morphology in an Anode-Free Lithium Metal Battery

The interrelation is explored between external pressure (0.1, 1, and 10 MPa), solid electrolyte interphase (SEI) structure/morphology, and lithium metal plating/stripping behavior. To simulate anode-free lithium metal batteries (AF-LMBs) analysis is performed on “empty” Cu current collectors in standard carbonate electrolyte. Lower pressure promotes organic-rich SEI and macroscopically heterogeneous, filament-like Li electrodeposits interspersed with pores. Higher pressure promotes inorganic F-rich SEI with more uniform and denser Li film. A “seeding layer” of lithiated pristine graphene (pG@Cu) favors an anion-derived F-rich SEI and promotes uniform metal electrodeposition, enabling extended electrochemical stability at a lower pressure. State-of-the-art electrochemical performance is achieved at 1MPa: pG-enabled half-cell is stable after 300 h (50 cycles) at 1 mA cm⁻² rate −3 mAh cm⁻² capacity (17.5 µm plated/stripped), with cycling Coulombic efficiency (CE) of 99.8%. AF-LMB cells with high mass loading NMC622 cathode (21 mg cm⁻²) undergo 200 cycles with a CE of 99.4% at C/5-charge and C/2-discharge (1C = 178 mAh g⁻¹). Density functional theory (DFT) highlights the differences in the adsorption energy of solvated-Li⁺ onto various crystal planes of Cu (100), (110), and (111), versus lithiated/delithiated (0001) graphene, giving insight regarding the role of support surface energetics in promoting SEI heterogeneity.     

Spatial Confinement of Sn/TiO2 Nanoparticles in Hollow Mesoporous Carbon Spheres Opal for Stable Zn Metal Anodes

The sluggish Zn²⁺ diffusion and high nucleation energy barrier induce uncontrolled growth of Zn dendrites and detrimental parasitic reactions, severely hampering the commercialization of Zn metal anodes (ZMAs). Herein, hollow mesoporous carbon sphere opal with confined Sn/TiO₂ clusters (HMCSST) is designed as the host to spatially regulate the Zn deposition. Owing to the capillary effect of the ordered hierarchical porous structure, the mass diffusion can be dramatically accelerated to promote a fast deposition kinetics at the interface between ZMA and electrolyte. Besides, the encapsulated ultrafine Sn/TiO₂ clusters serve as zincophilic sites to achieve both the uniform Zn deposition on the hierarchical porous opal host and the high thermodynamic stability of ZMAs. Benefiting from the structural and componential merits, the HMCSST host effectively reduces the activation energy to enable a temporal-spatial ordering of Zn nucleation and growth. As expected, the stable HMCSST-Zn electrode guarantees steady Zn platting/stripping with long-term stability over 1300 h in a symmetrical cell at a depth of discharge of 37.5%. As a proof-of-concept demonstration, an HMCSST-Zn||ammonium vanadate full cell shows a long lifespan over 5000 cycles at 10.0 A g⁻¹ with low polarization.     

Robust Hybrid Solid Electrolyte Interface Induced by Zn-Poor Electric Double Layer for A Highly Reversible Zinc Anode

Aqueous Zn-ion batteries (AZIBs) show great potential in new energy storage devices due to low cost, inherent safety, and environmental friendliness. However, the severe dendrites and side reactions on the anode greatly constrain their practical application. Herein, a novel colloidal electrolyte composed of ZnSO₄ and sodium carboxymethyl cellulose (CMC-Na) has been developed for inhibiting dendrite growth on Zn anode. Molecular dynamics (MD) simulation confirms that CMC-Na alters the electric double layer (EDL) structure of Zn anode surface to reduce the content of water and SO₄²⁻ and inhibit side reactions. More importantly, an organic/inorganic hybrid solid electrolyte interface (SEI) layer is in situ constructed during the cycling, which enables ultrastable Zn plating/stripping (> 2000 h) under high current density (5 mA cm⁻², 5 mAh cm⁻²) and high coulombic efficiency (99.8%) for more than 1000 cycles. Meanwhile, zinc-ion hybrid capacitors (ZIHCs) with the colloidal electrolyte exhibit a favorable capacitance retention of 97% after 15000 cycles at the current density of 2 A g⁻¹. Even at a high current density of 5 A g⁻¹, it still has a capacitance retention of 96% after 30000 cycles. This study presents a novel electrolyte strategy for the formation of ultrastable electrode-electrolyte interfaces in AZIBs.     

Construction of Stable Li2O-Rich Solid Electrolyte Interphase for Practical PEO-Based Li-Metal Batteries

Polyethylene oxide (PEO)-based solid polymer electrolytes (SPE) have garnered recognition as highly promising candidates for advanced lithium-metal batteries. However, the practical application of PEO-based SPE is hindered by its low critical current density (CCD) resulting from undesired dendrite growth. In this study, a PEO-based SPE that exhibits an ultra-high CCD (4 mA cm⁻²) is presented and enhanced lithium ionic conductivity through the incorporation of small amounts of P₂S₅ (PS). The crystalline Li₂O-rich and P/S-containing solid electrolyte interphase (SEI) is revealed by cryo-electron microscope (cryo-EM) and Time of flight secondary ion mass spectrometry (TOF-SIMS), which inhibits dendrite growth and adverse reactions between SPE and reductive lithium, thus offering a spherical growth behavior for dendrite-free lithium metal anode. Consequently, utilizing the PS-integrated SPE, a Li-Li symmetric cell demonstrates reduced resistance during operation, enabling stable cycles exceeding 200 hours at 0.5 mA cm⁻² and 0.5 mAh cm⁻², a stringent test condition for PEO-based electrolytes. Moreover, a Li/SPE/LiFePO₄ (LFP) pouch cell exhibits 80% capacity retention after 100 cycles with 50 µm Li and 30 µm PEO electrolyte, showcasing its potential for practical applications.     

Ultrathin Reed Membranes: Nature's Intimate Ion-Regulation Skins Safeguarding Zinc Metal Anodes in Aqueous Batteries

The practical realization of aqueous zinc-ion batteries relies crucially on effective interphases governing Zn electrodeposition chemistry. In this study, an innovative solution by introducing an ultrathin (≈2 µm) biomass membrane as an intimate artificial interface, functioning as nature's ion-regulation skin to protect zinc metal anodes is proposed. Capitalizing on the inherent properties of natural reed membrane, including multiscale ion transport tunnels, abundant ─OH groups, and remarkable mechanical integrity, the reed membrane demonstrates efficacy in regulating uniform and rapid Zn²⁺ transport, promoting desolvation, and governing Zn (002) plane electrodeposition. Importantly, a unique in situ electrochemical Zn─O bond formation mechanism between the reed membrane and Zn electrode upon cycling is elucidated, resulting in a robustly adhered interface covering on the zinc anode surface, ultimately ensuring remarkable dendrite-free and highly reversible Zn anodes. Consequently, the approach achieves a prolonged cycle life for over 1450 h at 3 mA cm⁻²/1.5 mAh cm⁻² in symmetric Zn//Zn cells. Moreover, exceptional cyclic performance (88.95%, 4000 cycles) is obtained in active carbon-based cells with an active mass loading of 5.8 mg cm⁻². The approach offers a cost-effective and environmentally friendly strategy for achieving stable and reversible zinc anodes for aqueous batteries.     

Uniform High Ionic Conducting Lithium Sulfide Protection Layer for Stable Lithium Metal Anode

Artificial solid‐electrolyte interphase (SEI) is one of the key approaches in addressing the low reversibility and dendritic growth problems of lithium metal anode, yet its current effect is still insufficient due to insufficient stability. Here, a new principle of “simultaneous high ionic conductivity and homogeneity” is proposed for stabilizing SEI and lithium metal anodes. Fabricated by a facile, environmentally friendly, and low‐cost lithium solid‐sulfur vapor reaction at elevated temperature, a designed lithium sulfide protective layer successfully maintains its protection function during cycling, which is confirmed by both simulations and experiments. Stable dendrite‐free cycling of lithium metal anode is realized even at a high areal capacity of 5 mAh cm^?2, and prototype Li–Li₄Ti₅O₁₂ cell with limited lithium also achieves 900 stable cycles. These findings give new insight into the ideal SEI composition and structure and provide new design strategies for stable lithium metal batteries.     

Coordination Engineering of N,O Co-Doped Cu Single Atom on Porous Carbon for High Performance Zinc Metal Anodes

Traditional challenges of poor cycling stability and low Coulombic efficiency in Zinc (Zn) metal anodes have limited their practical application. To overcome these issues, this work introduces a single metal-atom design featuring atomically dispersed single copper (Cu) atoms on 3D nitrogen (N) and oxygen (O) co-doped porous carbon (CuNOC) as a highly reversible Zn host. The CuNOC structure provides highly active sites for initial Zn nucleation and further promotes uniform Zn deposition. The 3D porous architecture further mitigates the volume changes during the cycle with homogeneous Zn²⁺ flux. Consequently, CuNOC demonstrates exceptional reversibility in Zn plating/stripping processes over 1000 cycles at 2 and 5 mA cm⁻² with a fixed capacity of 1 mAh cm⁻², while achieving stable operation and low voltage hysteresis over 700 h at 5 mA cm⁻² and 5 mAh cm⁻². Furthermore, density functional theory calculations show that co-doping N and O on porous carbon with atomically dispersed single Cu atoms creates an efficient zincophilic site for stable Zn nucleation. A full cell with the CuNOC host anode and high loading V₂O₅ cathode exhibits outstanding rate-capability up to 5 A g⁻¹ and a stable cycle life over 400 cycles at 0.5 A g⁻¹.     

Inducing the Preferential Growth of Zn (002) Plane for Long Cycle Aqueous Zn-Ion Batteries

Uncontrolled growth of Zn dendrites is the main reason for the short-circuit failure of aqueous Zn-ion batteries. Using electrolyte additives to manipulate the crystal growth is one of the most convenient strategies to mitigate the dendrite issue. However, most additives would be unstable during cycling due to the structural reconstruction of the deposition layer. Herein, it is proposed to use 1-butyl-3-methylimidazolium cation (BMIm⁺ ion) as an electrolyte additive, which could steadily induce the preferential growth of (002) plane and inhibit the formation of Zn dendrites. Specifically, BMIm⁺ ion will be preferentially adsorbed on (100) and (101) planes of Zn anodes, forcing Zn²⁺ ion to deposit on the (002) plane, thus inducing the preferential growth of the (002) plane and forming a flat and compact deposition layer. As a result, the Zn anode cycles for 1000 h at10 mA cm⁻² and 10 mAh cm⁻² as well as a high Coulombic efficiency of 99.8%. Meanwhile, the NH₄V₄O₁₀||Zn pouch cell can operate stably for 240 cycles at 0.4 A g⁻¹. The BMIm⁺ ion additive keeps a stable effect on the structural reconstruction of the Zn anode during the prolonged cycling.     

Tailoring Lithium Deposition via an SEI‐Functionalized Membrane Derived from LiF Decorated Layered Carbon Structure

Lithium (Li) metal is a key anode material for constructing next generation high energy density batteries. However, dendritic Li deposition and unstable solid electrolyte interphase (SEI) layers still prevent practical application of Li metal anodes. In this work, it is demonstrated that an uniform Li coating can be achieved in a lithium fluoride (LiF) decorated layered structure of stacked graphene (SG), leading to the formation of an SEI‐functionalized membrane that retards electron transfer by three orders of magnitude to avoid undesirable Li deposition on the top surface, and ameliorates Li⁺ ion migration to enable uniform and dendrite‐free Li deposition beneath such an interlayer. Surface chemistry analysis and density functional theory calculations demonstrate that these beneficial features arise from the formation of C–F_x surface components on the SG sheets during the Li coating process. Based on such an SEI‐functionalized membrane, stable cycling at high current densities up to 3 mA cm^?2 and Li plating capacities up to 4 mAh cm^?2 can be realized in LiPF₆/carbonate electrolytes. This work elucidates the promising strategy of modifying Li plating behavior through the SEI‐functionalized carbon structure, with significantly improved cycling stability of rechargeable Li metal anodes.     

Interface Engineering for Lithium Metal Anodes in Liquid Electrolyte

Interfacial chemistry between lithium metal anodes and electrolytes plays a vital role in regulating the Li plating/stripping behavior and improving the cycling performance of Li metal batteries. Constructing a stable solid electrolyte interphase (SEI) on Li metal anodes is now understood to be a requirement for progress in achieving feasible Li‐metal batteries. Recently, the application of novel analytical tools has led to a clearer understanding of composition and the fine structure of the SEI. This further promoted the development of interface engineering for stable Li metal anodes. In this review, the SEI formation mechanism, conceptual models, and the nature of the SEI are briefly summarized. Recent progress in probing the atomic structure of the SEI and elucidating the fundamental effect of interfacial stability on battery performance are emphasized. Multiple factors including current density, mechanical strength, operating temperature, and structure/composition homogeneity that affect the interfacial properties are comprehensively discussed. Moreover, strategies for designing stable Li‐metal/electrolyte interfaces are also reviewed. Finally, new insights and future directions associated with Li‐metal anode interfaces are proposed to inspire more revolutionary solutions toward commercialization of Li metal batteries.     

An Anion‐Tuned Solid Electrolyte Interphase with Fast Ion Transfer Kinetics for Stable Lithium Anodes

The spatial distribution and transport characteristics of lithium ions (Li⁺) in the electrochemical interface region of a lithium anode in a lithium ion battery directly determine Li⁺ deposition behavior. The regulation of the Li⁺ solvation sheath on the solid electrolyte interphase (SEI) by electrolyte chemistry is key but challenging. Here, 1 m lithium trifluoroacetate (LiTFA) is induced to the electrolyte to regulate the Li⁺ solvation sheath, which significantly suppresses Li dendrite formation and enables a high Coulombic efficiency of 98.8% over 500 cycles. With its strong coordination between the carbonyl groups (C?O) and Li⁺, TFA^? modulates the environment of the Li⁺ solvation sheath and facilitates fast desolvation kinetics. In addition, due to relatively smaller lowest unoccupied molecular orbital energy than solvents, TFA^? has a preferential reduction to produce a stable SEI with uniform distribution of LiF and Li₂O. Such stable SEI effectively reduces the energy barrier for Li⁺ diffusion, contributing to low nucleation overpotential, fast ion transfer kinetics, and uniform Li⁺ deposition with high cycling stability. This work provides an alternative insight into the design of interface chemistry in terms of regulating anions in the Li⁺ solvation sheath. It is anticipated that this anion‐tuned strategy will pave the way to construct stable SEIs for other battery systems.     

Temperature-Mediated Dynamic Lithium Loss and its Implications for High-Efficiency Lithium Metal Anodes

Lithium (Li) metal has been strongly regarded as the ultimate anode option for next-generation high-energy-density batteries. Nevertheless, the insufficient Coulombic efficiency induced by the extensive active Li loss largely hinders the practical operation of Li metal batteries under wide temperature range. Herein, the temperature-mediated dynamic growth of inactive Li from −20 to 60°C via titration gas chromatograph measurements is quantitatively decoupled. Combined X-ray photoelectronic spectroscopy, cryo-transmission electronic microscopy, and scanning electronic microscopy methods depicted that both solid electrolyte interphase (SEI) characteristics and Li deposition compactness can be profoundly manipulated by working temperature. The elevation of temperature is found to fundamentally aggravate the parasitic reactions and deteriorate the spatial uniformity of SEI, yet promote the lateral growth of Li by kinetic reason. The opposite effects of temperature on SEI properties and Li deposition compactness can properly explain the intricate temperature-dependent growth rates of SEI-Li⁺ and dead Li⁰ capacity loss observed under titration gas chromatograph measurements. Design implications towards more stable Li metal anodes with higher reversibility can thus be yielded.     

Compact 3D Copper with Uniform Porous Structure Derived by Electrochemical Dealloying as Dendrite‐Free Lithium Metal Anode Current Collector

The development of lithium (Li) metal anodes Li metal batteries faces huge challenges such as uncontrolled Li dendrite growth and large volume change during Li plating/stripping, resulting in severe capacity decay and high safety hazards. A 3D porous copper (Cu) current collector as a host for Li deposition can effectively settle these problems. However, constructing a uniform and compact 3D porous Cu structure is still an enormous challenge. Herein, an electrochemical etching method for Cu–Zinc (Zn) alloy is reported to precisely engrave a 3D Cu structure with uniform, smooth, and compact porous network. Such a continuous structure endows 3D Cu excellent mechanical properties and high electrical conductivity. The uniform and smooth pores with a large internal surface area ensures well dispersed current density for homogeneous Li metal deposition and accommodation. A smooth and stable solid electrolyte interphase is formed and meanwhile Li dendrites and dead Li are effectively suppressed. The Li metal anode conceived 3D Cu current collector can stably cycle for 400 h under an Li plating/stripping capacity of 1 mA h cm^?2 and a current density of 1 mA cm^?2. The Li@3D Cu||LiFePO₄ full cells present excellent cycling and rate performances. The electrochemical dealloying is a robust method to construct 3D Cu current collectors for dendrite‐free Li metal anodes.     

In Situ Generation of Artificial Solid‐Electrolyte Interphases on 3D Conducting Scaffolds for High‐Performance Lithium‐Metal Anodes

Rational structure design of the current collector along with further engineering of the solid‐electrolyte interphases (SEI) layer is one of the most promising strategies to achieve uniform Li deposition and inhibit uncontrolled growth of Li dendrites. Here, a Li₂S layer as an artificial SEI with high compositional uniformity and high lithium ion conductivity is in situ generated on the surface of the 3D porous Cu current collector to regulate homogeneous Li plating/stripping. Both simulations and experiments demonstrate that the Li₂S protective layer can passivate the porous Cu skeleton and balance the transport rate of lithium ions and electrons, thereby alleviating the agglomerated Li deposition at the top of the electrode or at the defect area of the SEI layer. As a result, the modified current collector exhibits long‐term cycling of 500 cycles at 1 mA cm^?2 and stable electrodeposition capabilities of 4 mAh cm^?2 at an ultrahigh current density of 4 mA cm^?2. Furthermore, full batteries (LiFePO₄ as cathode) paired with this designed 3D anode with only ≈200% extra lithium show superior stability and rate performance than the batteries paired with lithium foil (≈3000% extra lithium). These explorations provide new strategies for developing high‐performance Li metal anodes.     

Boosting Superior Lithium Storage Performance of Alloy‐Based Anode Materials via Ultraconformal Sb Coating–Derived Favorable Solid‐Electrolyte Interphase

Alloy materials such as Si and Ge are attractive as high‐capacity anodes for rechargeable batteries, but such anodes undergo severe capacity degradation during discharge–charge processes. Compared to the over‐emphasized efforts on the electrode structure design to mitigate the volume changes, understanding and engineering of the solid‐electrolyte interphase (SEI) are significantly lacking. This work demonstrates that modifying the surface of alloy‐based anode materials by building an ultraconformal layer of Sb can significantly enhance their structural and interfacial stability during cycling. Combined experimental and theoretical studies consistently reveal that the ultraconformal Sb layer is dynamically converted to Li₃Sb during cycling, which can selectively adsorb and catalytically decompose electrolyte additives to form a robust, thin, and dense LiF‐dominated SEI, and simultaneously restrain the decomposition of electrolyte solvents. Hence, the Sb‐coated porous Ge electrode delivers much higher initial Coulombic efficiency of 85% and higher reversible capacity of 1046 mAh g^?1 after 200 cycles at 500 mA g^?1, compared to only 72% and 170 mAh g^?1 for bare porous Ge. The present finding has indicated that tailoring surface structures of electrode materials is an appealing approach to construct a robust SEI and achieve long‐term cycling stability for alloy‐based anode materials.     

Self-Regulating Interfacial Space Charge through Polyanion Repulsion Effect towards Dendrite-Free Polymer Lithium-Metal Batteries

Uncontrolled transport of anions leads to many issues, including concentration polarization, excessive interface side reactions, and space charge-induced lithium dendrites at the anode/electrolyte interface, which severely deteriorates the cycling stability of lithium metal batteries. Herein, an asymmetrical polymer electrolyte modified by a boron-containing single-ion conductor (LiPVAOB), is designed to inhibit the nonuniform aggregation of free anions in the vicinity of the lithium anode through the repulsion effect improving the lithium-ion transference number to 0.63. This LiPVAOB exerts a repulsion interaction with free anions even at a long distance and a selective effect for free anions transport, which diminishes uneven aggregation of free anions at the interface and suppresses space charges-induced lithium dendrites growth. Consequently, the assembled Li||Li cell delivers an ultra-long cycle for over 5400 h. The Li||LiFePO₄ cell exhibits outstanding cycle performance with a capacity retention of 93% over 4500 cycles. In particular, the assembled high-voltage Li||Li_1.2Ni_0.2Mn_0.6O₂ cell (charged to 4.8 V) exhibits good cycle stability with a high specific capacity of 245 mAh g⁻¹. This designed polymer electrolyte provides a promising strategy for regulating ion transport to inhibit space charge-induced lithium dendrite growth for high-performance lithium metal batteries.     

Hard Carbon Anodes and Novel Electrolytes for Long‐Cycle‐Life Room Temperature Sodium‐Sulfur Full Cell Batteries

A novel combination of hard carbon anode sodium pre‐loading and a tailored electrolyte is used to prepare room temperature sodium‐sulfur full cell batteries. The electrochemical loading with sodium ions is realized in a specific mixture of diethyl carbonate, ethylene carbonate, and fluoroethylene carbonate electrolyte in order to create a first solid electrolyte interface (SEI) on the anode surface. Combining such anodes with a porous carbon/sulfur composite cathode results in full cells with a significantly decreased polysulfide shuttle when compared to half cells combined with metallic sodium anodes. Further optimization involves the use of Na₂S/P₂S₅ doped tetraethylene glycol dimethyl ether based electrolyte in the full cell for the formation of a second SEI, reducing polysulfide shuttle even further. More importantly, the electrochemical discharge processes in the cell are improved by adding this dissolved complexation agent to the electrolyte. As a result of this combination sodium‐sulfur cells with tailored cathode materials and electrolytes can achieve high discharge capacities up to 980 mAh g^?1_sulfur and 1000 cycles with 200 mAh g^?1_sulfur remaining capacity, at room temperature.