Lithium Metal Anode Research Articles

Lithium Plating Using a Thermoplastic Vulcanizate Electrolyte

Lithium metal anodes have generated significant interest due to their high theoretical capacity. However, issues such as dendrite growth or cell failure caused by lithium loss with either liquid electrolytes or solid polymer electrolytes (SPEs) have hindered its widespread commercialization. In this work, we report on the electrochemical characterization of symmetric Li-SPE-Li cells made with a thermoplastic vulcanizate electrolyte, PCl:HNBR LiTFSI. Full plating of the lithium metal (LiM) electrode was achieved at 100 μA.cm−2 in pressurized pouch cells. This was confirmed ex situ using scanning electron microscopy which showed the absence of dendrites. The Sand equation was employed at higher current densities to determine that the lithium diffusion coefficient at 60 °C is 1.7 × 10−8 cm2.s−1. The calculated threshold current density j* was approximately 200 μA.cm−2. The determination of the theoretical current density limit may provide critical information for the understanding of the behavior of cathode materials during cycling with lithium metal. Cell failure at high polarization or from short circuiting was experimentally confirmed in symmetric Li-Li cells where 100 cycles were performed at a current density below j* with 0.1 mAh.cm−2 of charge per cycle, while 0.5 mAh.cm−2 of charge rapidly induced cell failure.

Functionalized fillers as “ions relay stations” enabling Li+ ordered transport in quasi-solid electrolytes for high-stability lithium metal batteries

Quasi–solid–state lithium–metal batteries (QSLMBs) are promising candidates for next–generation battery systems due to their high energy density and enhanced safety. However, their practical application has been hindered by low ionic conductivity and the growth of lithium dendrites. To achieve ordered transport of Li+ ions in quasi–solid electrolytes (QSEs), improve ionic conductivity, and homogenize Li+ fluxes on the surface of the lithium metal anode (LMA), we propose a novel method. This method involves constructing “ion relay stations” in QSEs by introducing cyano–functionalized boron nitride nanosheets into pentaerythritol tetraacrylate (PETEA) –based polymer electrolytes. The functionalized boron nitride nanosheets promote the dissociation of lithium salts through ion–dipole interactions, optimizing the solvated structure to facilitate the orderly transport of Li+ ions, resulting in an ionic conductivity of 2.5 × 10−3 S cm−1 at 30 °C. Notably, this strategy regulates the Li+ distribution on the surface of the LMA, effectively inhibiting the growth of lithium dendrites. Li||Li symmetrical cells using this type of electrolyte maintain stability for over 2000 h at 2 mA cm−2 and 2 mAh cm−2. Additionally, with a high LiNi0.8Co0.1Mn0.1O2 (NCM811) loading of 8.5 mg cm−2, the cells exhibit excellent cycling performance, retaining a high capacity after 400 cycles. This innovative QSE design strategy represents a significant advancement towards the development of high–performance QSLMBs.

Wide-temperature and high-voltage Li||LiCoO2 cells enabled by a nonflammable partially-fluorinated electrolyte with fine-tuning solvation structure

Efficient, safe, and reliable energy output from high-energy-density lithium metal batteries (LMBs) at all climates is crucial for portable electronic devices operating in complex environments. The performance of corresponding cathodes and lithium (Li) metal anodes, however, faces significant challenges under such demanding conditions. Herein, a nonflammable electrolyte for high-voltage Li||LCO cells has been designed, including partially-fluorinated ethyl 4,4,4-trifluorobutyrate (ETFB) as the key solvent, guided by theoretical calculations. With this ETFB-based electrolyte, Li||LCO cells exhibit enhanced reversible capacities and superior capacity retention at an elevated charge voltage of 4.5 V and a wide operating temperature range spanning from −60 °C to 70 °C. The cells achieve 67.1% discharge capacity at −60 °C, relative to room temperature capacity, and 85.9% 100th-cycle retention at 70 °C. The outstanding properties are attributed to the LiF-rich interphases formed in the ETFB-based electrolyte with a fine-tuned solvation structure, in which the coordination environment in the vicinity of Li+ cations and the distance between anion and solvents are subtly adjusted by introducing ETFB. This solvation structure has been mutually elucidated through joint spectra characterizations and atomistic simulations. This work presents a new strategy for the design of electrolytes to achieve all-climate reliable and safe application of LMBs.

Preparation of polyelectrolyte based on bottle brush Polyethylene glycol‐Poly(N‐isopropylacrylamide) copolymers

AbstractThe increased demand for high energy‐density batteries led to using lithium metal (Li) anode. However, safety issues associated with Li anode encouraged the researchers to use less reactive and safer electrolytes with higher electrochemical stability. High ionic conductivity (σ), wider electrochemical stability window, and higher mechanical strength alongside the ability to self‐heal possible structural damages were at the center of focus for developing efficient solid electrolytes. In this regard, we developed a group of solid polymer electrolytes (SPEs) with high σ and electrochemical stability. In this regard, bottle brush polyethylene glycol (bbPEG) was synthesized using a chain transfer reaction. Polynipaam (PNIPAAM) blocks were also incorporated into the structure to prepare a block copolymer based on PNIPAM‐bbPEG‐PNIMAM represented by the ABA structure. The block copolymer was then blended with polyvinylidene fluoride (PVDF) with the block copolymer to PVDF weight ratio of 7:2% and 25% bis(trifluoromethane) sulfonamide (TFSI) salt was added and the final mixture was UV‐cured. The results indicated that the final SPE possessed high ionic conductivity with a relatively high lithium‐ion transference number () of 0.416 and the σ of 1.265 × 10−5 S/cm at 25°C.

Realizing interfacial coupled electron/ion transport through reducing the interfacial oxygen density of carbon skeletons for high-performance lithium metal anodes

Lithium plating/stripping occurs at the anode/electrolyte interface which involves the flow of electrons from the current collector and the migration of lithium ions from the solid-electrolyte interphase (SEI). The dual continuous rapid transport of interfacial electron/ion is required for homogeneous Li deposition. Herein, we propose a strategy to improve the Li metal anode performance by rationally regulating the interfacial electron density and Li ion transport through the SEI film. This key technique involves decreasing the interfacial oxygen density of biomass-derived carbon host by regulating the arrangement of the celluloses precursor fibrils. The higher specific surface area and lower interfacial oxygen density decrease the local current density and ensure the formation of thin and even SEI film, which stabilized Li+ transfer through the Li/electrolyte interface. Moreover, the improved graphitization and the interconnected conducting network enhance the surface electronegativity of carbon and enable uninterruptible electron conduction. The result is continuous and rapid coupled interfacial electron/ion transport at the anode/electrolyte reaction interface, which facilitates uniform Li deposition and improves Li anode performance. The Li/C anode shows a high initial Coulombic efficiency of 98% and a long-term lifespan of over 150 cycles at a practical low N/P (negative-to-positive) ratio of 1.44 in full cells.

Multi-Component Lithiophilic Alloy Film Modified Cu Current Collector for Long-Life Lithium Metal Batteries by a Novel FCVA Co-Deposition System.

Surface modification of Cu current collectors (CCs) is proven to be an effective method for protecting lithium metal anodes. However, few studies have focused on the quality and efficiency of modification layers. Herein, a novel home-made filtered cathode vacuum arc (FCVA) co-deposition system with high modification efficiency, good repeatability and environmental friendliness is proposed to realize the wide range regulation of film composition, structure and performance. Through this system, ZnMgTiAl quaternary alloy films, which have good affinity with Li are successfully constructed on Cu CCs, and the fully enhanced electrochemical performances are achieved. Symmetrical cells constructed with modified CCs maintained a fairly low voltage hysteresis of only 13mV after 2100h at a current density of 1mA cm-2. In addition, the capacity retention rate is as high as 75.0% after 100 cycles in the full cells. The influence of alloy films on the dynamic evolution process of constructing stable artificial solid electrolyte interphase (SEI) layer is revealed by in situ infrared (IR) spectroscopy. This work provides a promising route for designing various feasible modification films for LMBs, and it displays better industrial application prospects than the traditional chemical methods owing to the remarkable controllability and scale-up capacity.

Study on an Interpenetrating Artificial SEI for Lithium Metal Anode Modification and Fast Charging Characterization.

Artificial SEI is one of the effective strategies to improve lithium dendrites and suppress side reactions. However, the role of SEI components and distribution on the modification of the lithium metal anode remains unclear. Therefore, in this study, the oxygen-sulfur (O-S) component and its distribution in SEI were modulated by designing experiments, and then the mechanism of its action was deeply investigated. The study is based on an in-depth analysis of the properties of lithium sulfide (Li2S) and lithium oxide (Li2O) as SEI layer materials and effectively combines them in an ether electrolyte environment to form an innovative SEI structure. The experimental results show that the optimal SEI modulation condition is O120-S10. O120-S10 significantly improves the kinetic performance of electrochemical reactions, reduces the film resistance, and achieves cycling stability of up to 2100 h during high-capacity lithium deposition/stripping at 5 mAh cm-2. When used in conjunction with a ternary cathode material (NCM811), the O120-S10 demonstrates excellent performance under high rate charge/discharge conditions at 10C. After 1500 cycle tests, the battery's specific capacity was maintained at 90 mAh g-1 and the Coulombic efficiency reached 98.52%. Through X-ray photoelectron spectroscopy (XPS) analysis, the vertical structure and ratio distribution of components in SEI were revealed in detail, and the optimal component ratios of Li2S 46.48%, Li2O 46.02%, and Li2CO3 7.50% were determined. The mechanism of action is to achieve a 1 + 1 > 2 superlinear synergistic effect and fast charging performance by combining the ability of Li2O's low lithium ion diffusion barrier with Li2S's ability to inhibit the growth of lithium dendrites.

Development and Optimization of Thin-Lithium-Metal Anodes with a Lithium Lanthanum Titanate Stabilization Coating for Enhancement of Lithium-Sulfur Battery Performance.

Lithium-ion batteries are dominating high-energy-density energy storage for 30 years. However, their development approaches theoretical limits, spurring the development of lithium-sulfur cells that achieve high energy densities through reversible electrochemical conversion reactions. Nevertheless, the commercialization of lithium-sulfur cells is hindered by practical challenges associated primarily with the use of thick-lithium anodes, low-loading sulfur cathodes, and high electrolyte-to-sulfur ratios, which prevent realization of the cells' full potential in terms of electrochemical and material performance. To solve these extrinsic and intrinsic problems, the effect of lithium-metal thickness on the electrochemical behavior of lithium-sulfur cells with high-loading sulfur cathodes in lean-electrolyte configurations is investigated. Specifically, lithium lanthanum titanate (LLTO), a solid electrolyte, is utilized to form an ionically/electronically conductive coating to stabilize lithium-metal anodes, thereby enhancing their lithium-ion pathways and interfacial charge transfer. Electrochemical analyses reveal that an LLTO coating significantly reduces excessive reactions between lithium metal and an electrolyte, thereby minimizing lithium consumption and electrolyte depletion. Further, LLTO-stabilized lithium anodes improve lithium-sulfur cell performance, and most importantly, allow the fabrication of thin-lithium, high-loading-sulfur cells that open a pathway toward high-energy-density batteries.

Exploring interfacial stability for Zr-doped sulfide solid electrolyte with first-principle calculation

First-principles calculations are employed to investigate the interfacial properties on the Zr-doped sulfide solid electrolytes. Theoretical calculation results show that the PS4 tetrahedral structure near the Li/Li3PS4 interface is severely damaged, whereas the Zr-doped sulfide solid electrolyte interface structure has a slight deformation. The Li ions migration energy barrier on the Zr-doped sulfide solid electrolyte interface is relatively lower than that on the Li/Li3PS4. Moreover, the stress-strain analysis indicates that the Li/Li3PS4 interface structure experiences a maximum strain of only 6 %, while the Zr-doped sulfide solid electrolyte interface structure experiences a maximum strain of 10 %. This may be attributed to the ability of Zr doping to prevent S2− diffusion into the lithium metal anode and stabilize the Li ion transport skeleton. Therefore, Zr doping can improve the interface structure stability. This study will provide a useful perspective for designing high performance of solid electrolytes for the application of all-solid-state batteries.

Compositional Engineering of Lithium Metal Anode for High-Performance Garnet-Type Solid-State Lithium Battery.

Garnet-type solid-state lithium batteries (SSLBs) possess excellent potential owing to their safety and high energy density. However, fundamental barriers are deficient cycling stability and poor rate capability. The main concern lies in generating voids at the Li|garnet interface during Li stripping, stemming from the sluggish diffusion of Li atoms inside the bulk Li metal. Herein, a composite anode (AN@Li) containing Li-Al alloy, Li3N, and LiNO2 is designed by introducing aluminum nitrate into molten Li. The lower interfacial formation energies exhibited by Li-Al alloy, Li3N, and LiNO2 with garnet solid-state electrolyte (SSE) enhance the wettability of AN@Li toward SSE. Meanwhile, it affords efficient conductive pathways that facilitate Li+ diffusion in the bulk anode (not just on the surface). Impressively, the resulting symmetric cell with AN@Li electrodes achieves high critical current density (1.95mA cm-2) and long cycle life (6000h at 0.3mA cm-2). The SSLB coupled with LiFePO4 cathode and AN@Li anode enables stable cycling for 200 cycles at a high rate of 1 C with a retention of 96% and exhibiting outstanding rate capability (145.9 mAh g-1 at 2 C). This work provides practical insights for producing high-performance lithium metal anode for advanced garnet-type SSLBs.

Tailoring the Electrode‐Electrolyte Interface for Reliable Operation of All‐Climate 4.8 V Li||NCM811 Batteries

AbstractCombining high‐voltage nickel‐rich cathodes with lithium metal anodes is among the most promising approaches for achieving high‐energy‐density lithium batteries. However, most current electrolytes fail to simultaneously satisfy the compatibility requirements for the lithium metal anode and the tolerance for the ultra‐high voltage NCM811 cathode. Here, we have designed an ultra‐oxidation‐resistant electrolyte by meticulously adjusting the composition of fluorinated carbonates. Our study reveals that a solid‐electrolyte interphase (SEI) rich in LiF and Li2O is constructed on the lithium anode through the synergistic decomposition of the fluorinated solvents and PF6− anion, facilitating smooth lithium metal deposition. The superior oxidation resistance of our electrolyte enables the Li||NCM811 cell to deliver a capacity retention of 80 % after 300 cycles at an ultrahigh cut–off voltage of 4.8 V. Additionally, a pioneering 4.8 V‐class lithium metal pouch cell with an energy density of 462.2 Wh kg−1 stably cycles for 110 cycles under harsh conditions of high cathode loading (30 mg cm−2), low N/P ratio (1.18), and lean electrolytes (2.3 g Ah−1).

Roller-like Spore Carbon Sphere-Orientated Graphene Fibers Prepared via Rheological Engineering for Lithium Sulfur Batteries.

Flexible batteries with large energy densities, lightweight nature, and high mechanical strength are considered as an eager goal for portable electronics. Herein, we first propose free-standing graphene fiber electrodes containing roller-like orientated spore carbon spheres via rheological engineering. With the help of the orientated microfluidic cospinning technology and the plasma reduction method, spore carbon spheres are self-assembled and orientedly dispersed into numerous graphene flakes, forming graphene fiber electrodes enriched with internal rolling woven structures, which cannot only enhance the electrical contact between active materials but also effectively improve the mechanical strength and structure stability of graphene fiber electrodes. When the designed graphene fibers are combined with the active sulfur cathode and lithium metal anode, the assembled flexible lithium sulfur batteries possess superior electrochemical performance with high capacity (>1000 mA h g-1) and excellent cycling life as well as good mechanical properties. According to density functional theory and COMSOL simulations, the roller-like spore carbon sphere-orientated graphene fiber hosts provide reinforced trapping-catalytic-conversion behavior to soluble polysulfides and nucleation active sites to lithium metal, thus synergistically suppressing the shuttle effect of polysulfides at the cathode side and lithium dendrite growth at the anode side, thereby boosting the whole electrochemical properties of lithium sulfur batteries.

In Situ Fabrication of Solvent-Free Solid Polymer Electrolytes for Wide-Temperature All-Solid-State Lithium Metal Batteries.

All-solid-state lithium metal batteries (ASSLMBs) have been regarded as promising candidates to settle the safety issues of liquid electrolytes for rechargeable lithium batteries. However, the currently reported gel polymer electrolytes still have flammable liquid solvents, thus leading to the potential safety hazard. Here, solvent-free deep eutectic solid polymer electrolytes (SPEs) are designed and fabricated via an in situ polymerization, which are composed of a poly(vinylidene fluoride-hexafluoropropylene) (PVDF-HFP) electrospun membrane, succinonitrile (SN), poly(ethylene glycol) diacrylate (PEGDA200, Mn = 200 g mol-1), lithium bis(trifluoromethanesulfonyl)imide (LiTFSI), and lithium difluoro(oxalato)borate (LiDFOB). The deep eutectic solvent (DES) with SN/LiTFSI provides a superior room-temperature ionic conductivity, while the PEGDA200 precursor acts as cross-linking network to form SPEs under thermal initiation for free radical polymerization, and LiDFOB can form a stable solid electrolyte interface (SEI) layer. The PVDF-HFP electrospun membrane with a three-dimensional nanofibrous network structure for SN/PEGDA200/LiTFSI/LiDFOB SPEs exhibits a wide electrochemical stability window, high lithium-ion transference number, and good compatibility with the lithium metal anode. Furthermore, the obtained SPEs assembled with Li//LiMn0.6Fe0.4PO4, Li//LiFePO4, and Li//LiNi0.8Co0.1Mn0.1O2 asymmetric cells show excellent cycling performance and rate capability at a wide temperature. This strategy provides a promising path in designing high-energy-density ASSLMBs for practical application.

Few-layered graphene from cathodic exfoliation in binary solvents and application as a protective layer for lithium metal anodes

Electrochemical exfoliation is a top-down method recognized for its environmentally friendly and scalable approach for producing solution-processable graphene. Among its variation, cathodic exfoliation stands out for its potential in generating few-layer graphene with minimal defects. In this study, we developed a cathodic exfoliation method for graphite foil using a binary solvent system to produce graphene with a reduced number of layers. By employing a 0.1 M LiClO4 solution in a dimethyl sulfoxide and dimethyl carbonate solvents mixture at a 1:2 vol ratio, we enhanced the intercalation of solvated lithium ions into graphite, successfully exfoliating graphene with 5–6 layers. The exfoliated graphene exhibited a low defect density (ID/IG ∼0.05) and a C/O ratio of 33.2. Furthermore, when used as a coating on a separator, the exfoliated few-layered graphene (FLG) sheets demonstrated notable performance as a protective layer for Li metal anode in Li metal battery technology.

Tri-anion solvation structure electrolyte improves the electrochemical performance of Li||LiNi0.8Co0.1Mn0.1O2 batteries.

Li||LiNi0.8Co0.1Mn0.1O2 batteries,which consist of lithiummetal anode (LMA) matchedwith NCM811 cathode, have an energy density more than twice that of lithium ion battery (LIB).However, the unstable electrode/electrolyte interface still hinders its practical application.Ether electrolytes show promise in improving the stability of LMA and NCM811 cathodes.However, a robust and stableelectrode/electrolyte interface in Li||NCM811 batteries cannot be easily and efficiently achieved with most of the ether electrolytes reported in present studies. Herein, we present a straightforwardand efficient tri-anion synergistic strategy to overcome this bottleneck. The addition of ClO4- and NO3- anions to LiFSI-based ether electrolytes forms a unique solvation structure with tri-anion (FSI-/ClO4-/NO3-) participation(LB511).This structure not only enhances the electrochemical window of the ether electrolytes but also achieves a stable Li||NCM811batteries interface.The interaction between electrode and electrolyte is suppressed andan inorganic-rich (LiF/Li3N/LiCl) SEI/CEI layer is formed. Meanwhile, the coordination structure in the LB511 electrolyte increases the overpotential for Li deposition, resulting in a uniform and dense layer of deposition.Therefore,the Li||Cu cells using the LB511 electrolytehave an average CE of 99.6%.TheLi||NCM811 batteries was cycled stably for 250 cycles with a capacity retention of 81% in the LB511 electrolyte (N/P = 2.5, 0.5 C).

Metal-Free Polymer-Based Current Collector for High Energy Density Lithium-Metal Batteries.

The energy density of lithium-metal batteries (LMBs) relies substantially on the thickness of the lithium-metal anode. However, a bare, thin lithium foil electrode is vulnerable to fragmentation due to the inhomogeneity of the lithium stripping/plating process, disrupting the electron conduction pathway along the electrode. Accordingly, the current collector is an integral part to prevent the resulting loss of electronic conductivity. However, the common use of a heavy and lithiophobic Cu current collector results in a great anode mass increase and unsatisfactory lithium plating behavior, limiting both the achievable specific energy and the cycle life of LMBs. Herein, a metal-free polymer-based current collector is reported that allows for a substantial mass reduction, while simultaneously extending the cycle life of the lithium-metal anode. The specific mass of the ultra-light, 10µm thick polymer-based current collector is only 1.03mg cm-2, which is ≈11% of a 10 µm thick copper foil (8.96mg cm-2). As a result, LMB cells employing this novel current collector provide a specific energy of 448Wh kg-1, which is almost 18% higher than that of LMBs using the copper current collector (378Wh kg-1), and a greatly enhanced cycle life owing to a more homogeneous lithium deposition.

Electrospun Quasi‐Composite Polymer Electrolyte with Hydoxyl‐Anchored Aluminosilicate Zeolitic Network for Dendrite Free Lithium Metal Batteries

AbstractAll‐solid‐state lithium metal batteries have reshaped emerging safe battery technologies. However, their low metal ion transport and unstable electrode electrolyte interface make their mass production a huge question. To bridge the emerging solid state and traditional liquid electrolytes, we focus on Quasi‐Composite Polymer electrolytes (QCPE). Herein, we develop QCPE with active 3D alumino‐silicate zeolitic ion conduction pathways embedded in a polymer matrix using two techniques‐ solution casting and electrospinning. Electrospun QCPE outperforms Solution cast QCPE by achieving high amorphous behavior. Prompt elimination of solvent during electrospinning decreases bulk resistance and increases its ionic conductivity. The Zeolitic pathway anchored by hydroxyl groups of PVA polymer acts as a highway for Li+ ions. It exhibits highly stable platting stripping vs Li+/Li for 450 hours with low overpotential, confirming the interfacial compatibility and dendrite‐free cycling at lithium metal anode. Controlled lithium‐ion nucleation regulated by evenly distributed zeolitic pathway is an interesting front of this work. To test QCPE's performance in Lithium metal battery (LMB), the electrospun QCPE is used to fabricate LMB with LiFePO4 cathode. This battery system delivered a high capacity of 155 mAh g−1 at 0.1 C. In addition to the high performance, electrospun QCPE production is scalable at an industrial scale.

Leveraging Ion Pairing and Transport in Localized High-Concentration Electrolytes for Reversible Lithium Metal Anodes at Low Temperatures.

Coulombic efficiency of over 99% is rarely achieved for Li metal anode below -40°C, hindering the practical application of high-energy-density Li metal batteries under extreme conditions. Herein, limiting factors for Li metal reversibility are investigated utilizing ether-based localized high-concentration electrolytes of different solvent-diluent combinations. We find that along with the desolvation barrier, bulk ion transport properties including ionic conductivity, transference number, and diffusivity are also crucial factors for low-temperature Li deposition behavior. Superior Li metal reversibility was observed within the combination of the solvent with moderately weak solvating power and the diluent with minimal viscosity, highlighting the role of ion transport and the necessity for a trade-off with desolvation. The optimized electrolyte composed of lithium bis(fluorosulfonyl)imide, methyl n-propyl ether, and 1,1,2,2-tetrafluoroethyl methyl ether delivers exceptional Coulombic efficiency of 99.34% at -40°C and 98.96% at -60°C under a current density of 0.5 mA cm-2. Furthermore, Li||LiCoO2 (2.7 mAh cm-2) cells demonstrate impressive reversible capacity and cycling stability at these temperatures. This work sheds light on the less-recognized relevance of bulk ion transport to low-temperature performance and provides guidelines for the electrolyte design of Li metal batteries operating in cold environments.

ZnS Nanoseeds Sealed in N, P, S Co-Doped Carbon Hollow Rhombic Dodecahedra as a Superlithiophilic Host for Dendrite-Free Lithium Metal Anodes.

Lithium (Li) metal is considered ahopeful anode for next-generation Li-ion batteries thanks to its ultra-high theoretical specific capacity, extra-low theoretical density, and low negative potential. However, the uncontrolled growth of Li dendrites and volume fluctuation during plating/stripping processes severely hamper its commercial application. Herein, ZnS seeds sealed in N, P, S co-doped carbon hollow rhombic dodecahedra (ZnS@NPS-C HRD) is fabricated as a superlithiophilic host for Li metal anodes (LMAs) to solve the above problems. In addition, the Li nucleation and deposition mechanism on ZnS@NPS-C HRD is investigated by in situ optical microscopy, ex-situ X-ray diffraction, scanning electron microscopy, and theoretical calculations. Owing to the synergistic strategy of ZnS seeds-inducing nucleation and Li-limited growth, the as-prepared composite exhibits stability for 300 cycles in asymmetric cells and a long lifespan over 1100h in symmetric cells. Moreover, the ZnS@NPS-C HRD@Li|LiFePO4 full cell demonstrates a reversible capacity of 100.91mAhg-1 after 400 cycles at 1C.

Fluorine-Rich Electrolyte Additive for Achieving Dendrite-Free Lithium Anodes at Low Temperatures.

The practical application of lithium metal anodes is significantly impeded by poor interfacial stability and uncontrolled dendrite growth. Herein, we introduce methyl trifluoroacetate (MTFA), a low-melting-point small molecule, as an electrolyte additive in an ether-based electrolyte. This additive facilitates the formation of an in situ composite solid electrolyte interphase (SEI) layer that is rich in LiF and features an ester-based flexible matrix. The resulting composite layer exhibits high ionic conductivity and mechanical stability, effectively regulating the lithium deposition behavior over a broad temperature range and inhibiting dendrite formation. Based on MTFA, the Li||Li symmetrical cell achieves a lifespan exceeding 5000 h at room temperature and 800 h at -20 °C, both with ultralow overpotential and exceptional cycling stability. In Li||LiFePO4 full cells with a high-area loading (10.52 mg cm-2) and an N/P ratio of 1.68, an average capacity decay of merely 0.096% per cycle is observed over 200 cycles. Even at -20 °C, the Li||LiFePO4 cell shows a CE of over 99% and maintains stable cycling performance. This work provides an innovative approach for optimizing lithium metal anode interfaces and enhancing low-temperature operation capabilities through the use of electrolyte additives.