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1.
    
Toward improved understanding and control of the interactions of Li metal anodes with their processing environments, a combined X‐ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), and density functional theory (DFT) characterization of the effects that O2, CO2, and N2, the main gases in dry‐atmosphere battery production lines, induced on a reproducibly clean Li surface at room temperature is presented here. XPS measurements demonstrate that O2 is ten times more effective than CO2 at oxidizing metal Li. Notably, pure N2 is shown to not dissociate on clean metal Li. UPS results indicate that decomposition of O2 (CO2) reduces the work function of the Li surface by almost 1 eV, therefore increasing the reduction energy drive for the treated substrate by comparison to bare metallic Li. DFT simulations semiquantitatively account for these results on the basis of the effects of dissociative gas adsorption on the surface dipole density of the Li surface.  相似文献   

2.
    
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 LiNi1/3Mn1/3Co1/3O2 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.  相似文献   

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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–Fx 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.  相似文献   

6.
    
Lithium metal batteries (LMBs) are promising candidates for next‐generation energy storage due to their high energy densities on both weight and volume bases. However, LMBs usually undergo uncontrollable lithium deposition, unstable solid electrolyte interphase, and volume expansion, which easily lead to low Coulombic efficiency, poor cycling performance, and even safety hazards, hindering their practical applications for more than forty years. These issues can be further exacerbated if operated at high current densities. Here a stable lithium metal battery enabled by 3D porous poly‐melamine‐formaldehyde (PMF)/Li composite anode is reported. PMF with a large number of polar groups (amine and triazine) can effectively homogenize Li‐ion concentration when these ions approach to the anode surface and thus achieve uniform Li deposition. Moreover, the 3D structured anode can serve as a Li host to mitigate the volume change during Li stripping and plating process. Galvanostatic measurements demonstrate that the 3D composite electrode can achieve high‐lithium Coulombic efficiency of 94.7% at an ultrahigh current density of 10 mA cm?2 after 50 cycles with low hysteresis and smooth voltage plateaus. When coupled with Li4Ti5O12, half‐cells show enhanced rate capabilities and Coulombic efficiencies, opening great opportunities for high‐energy batteries.  相似文献   

7.
    
Lithium‐ion batteries (LIBs) with outstanding energy and power density have been extensively investigated in recent years, rendering them the most suitable energy storage technology for application in emerging markets such as electric vehicles and stationary storage. More recently, sodium, one of the most abundant elements on earth, exhibiting similar physicochemical properties as lithium, has been gaining increasing attention for the development of sodium‐ion batteries (SIBs) in order to address the concern about Li availability and cost—especially with regard to stationary applications for which size and volume of the battery are of less importance. Compared with traditional intercalation reactions, conversion reaction‐based transition metal oxides (TMOs) are prospective anode materials for rechargeable batteries thanks to their low cost and high gravimetric specific capacities. In this review, the recent progress and remaining challenges of conversion reactions for LIBs and SIBs are discussed, covering an overview about the different synthesis methods, morphological characteristics, as well as their electrochemical performance. Potential future research directions and a perspective toward the practical application of TMOs for electrochemical energy storage are also provided.  相似文献   

8.
    
Lithium (Li) metal anodes exhibits the potential to enable rechargeable Li batteries with a high energy density. However, the irreversible plating and stripping behaviors of Li metal anodes with high reactivity and dendrite growth when matching different cathodes in working cells are not fully understood yet. Herein the working manner of very thin Li metal anodes (50 µm, 10 mAh cm?2) is probed with different sequences of Li plating and stripping at 3.0 mA cm?2 and 3.0 mAh cm?2. Dendrite growth and dead Li forms on the surface of the initially plated Li electrode (P‐Li), while Li dendrites form in the pit of the initially stripped Li electrode (S‐Li). This induces the differences in reactive sites, distribution of dead Li, and voltage polarization of Li metal anodes. There is a gap of 15–20 and 13–16 mV for the end voltages between S‐Li and P‐Li during stripping and plating, respectively. When matching LiFePO4 and FePO4 cathodes, P‐Li | LiFePO4 cells exhibit a 30‐cycle longer lifespan with smaller end polarization due to differences in the sequences of Li plating and stripping. This contribution affords emerging working principles for actual Li metal anodes when matching lithium‐containing and lithium‐free cathodes.  相似文献   

9.
    
Although metallic lithium is regarded as the “Holy Grail” for next‐generation rechargeable batteries due to its high theoretical capacity and low overpotential, the uncontrollable Li dendrite growth, especially under high current densities and deep plating/striping, has inhibited its practical application. Herein, a 3D‐printed, vertically aligned Li anode (3DP‐VALi) is shown to efficiently guide Li deposition via a “nucleation within microchannel walls” process, enabling a high‐performance, dendrite‐free Li anode. Moreover, the microchannels within the microwalls are beneficial for promoting fast Li+ diffusion, supplying large space for the accommodation of Li during the plating/stripping process. The high‐surface‐area 3D anode design enables high operating current densities and high areal capacities. As a result, the Li–Li symmetric cells using 3DP‐VALi demonstrate excellent electrochemical performances as high as 10 mA cm?2/10 mAh cm?2 for 1500 h and 5 mA cm?2/20 mAh cm?2 for 400 h, respectively. Additionally, the Li–S and Li–LiFePO4 cells using 3DP‐VALi anodes present excellent cycling stability up to 250 and 800 cycles at a rate of 1 C, respectively. It is believed that these new findings could open a new window for dendrite‐free metal anode design and pave the way toward energy storage devices with high energy/power density.  相似文献   

10.
    
Lithium (Li) metal is one of the most promising anode materials to construct next‐generation rechargeable batteries owing to its ultrahigh theoretical capacity and the lowest electrochemical potential. Unfortunately, practical application of Li metal batteries is severely hindered by short lifespan and safety concerns caused by Li dendrite growth during cycling. Herein, a coaxial‐interweaved hybrid Li metal anode is proposed for dendrite inhibition that significantly improves the cycling stability of Li metal batteries. The hybrid Li metal anode is fabricated by Li composition into a 3D interweaved scaffold, where each fiber of the interwoven scaffold is composed of a conductive skeleton and a coaxial lithiophilic layer modified on the surface. The coaxial‐interweaved structure endows the hybrid anode with favored Li affinity to guide uniform Li deposition, sufficient channels for ion transportation and electron conduction, and enhanced stability during Li plating and stripping. Consequently, the hybrid Li metal anode affords high Coulombic efficiency over 98.5% for 750 cycles with dendrite‐free morphologies in half cells and improved capacity retention of 80.1% after 100 cycles in LiFePO4 full cells. The innovative coaxial‐interweaved hybrid Li metal anode demonstrates multiscale design strategy from lithiophilic modification to scaffold construction and promises the prospect of Li metal batteries for future applications.  相似文献   

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The application of lithium (Li) metal anodes in Li metal batteries has been hindered by growth of Li dendrites, which lead to short cycling life. Here a Li‐ion‐affinity leaky film as a protection layer is reported to promote a dendrite‐free Li metal anode. The leaky film induces electrokinetic phenomena to enhance Li‐ion transport, leading to a reduced Li‐ion concentration polarization and homogeneous Li‐ion distribution. As a result, the dendrite‐free Li metal anode during Li plating/stripping is demonstrated even at an extremely high deposition capacity (6 mAh cm?2) and current density (40 mA cm?2) with improved Coulombic efficiencies. A full cell battery with the leaky‐film protected Li metal as the anode and high‐areal‐capacity LiNi0.8Co0.1Mn0.1O2 (NCM‐811) (≈4.2 mAh cm?2) or LiFePO4 (≈3.8 mAh cm?2) as the cathode shows improved cycling stability and capacity retention, even at lean electrolyte conditions.  相似文献   

12.
    
The lithium dendrite, inducing short circuit and breaking solid electrolyte interphase (SEI) films, is deleterious to the stability of Li metal batteries due to the uncontrollable occurrence of miscellaneous stresses. In contrast to conventional suppression routes, herein a strategy is proposed via controlling SEI film broken regions to minimize releasing stress in terms of weaving lithium pits. Inspired by the principle of zippers, zipper‐like SEI films enable offering ordered pattern on the surface of Li anode via mechanical rolling. For the available cells, net‐like sewing/breaking patterns alternatively occur in Li plating/stripping. In the same electrolyte, a stable and dendrite‐free Li homogeneous growth is achieved.  相似文献   

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While the practical application of electrode materials depends intensively on the Li+ ion storage mechanisms correlating ultimately with the coulombic efficiency, reversible capacity, and morphology variation of electrode material upon cycling, only intercalation‐type electrode materials have proven viable for commercialization up to now. This paper reviews the promising anode materials of metal vanadates (MxVyOz, M = Co, Cu, Mn, Fe, Zn, Ni, Li) that have high capacity, low cost, and abundant resource, and also discusses the related Li+ ion storage mechanism. It is concluded that most of these (MxVyOz, M = Co, Cu, Mn, Fe, Zn, Ni) exhibit irreversible redox reactions upon lithiation/delithiation accompanied by large volume expansion, which is not favorable for industrial applications. In particular, Li3VO4 with specific intercalation Li+ ion storage mechanism and compatible merits of safety and energy density exhibits great potential for practical application. This review systematically summarizes the latest progress in Li3VO4 research, including the representative fabrication approaches for advanced morphology and state‐of‐the‐art technologies to boost performance and the morphology variation associated with Li+ ion storage mechanisms. Furthermore, an outlook on where breakthroughs for Li3VO4 may be most likely achieved will be provided.  相似文献   

14.
    
Rechargeable lithium‐based batteries are long considered as the most promising candidates for application in various electronic devices, electric vehicles, and even electrical grids owing to their ultrahigh energy densities. However, to date, metallic lithium‐based batteries are still far from practical applications due to the low Coulombic efficiency and fast capacity decay of lithium anodes. The poor electrochemical performances of metallic lithium anodes are inherently related to random growth of lithium dendrites and infinite volume charge of lithium anodes. In this review, the failure mechanisms of metallic lithium anodes are summarized and ascribed to the unstable and inhomogeneous solid electrolyte interphase, uneven distributions of electric field, and lithium‐ion flux during the lithium plating processes. Correspondingly, efficient strategies for mitigating these problems, including surficial engineering, electric field, and lithium‐ion flux regulation are discussed from the perspective of anode materials. Finally, an outlook is proposed for the design and fabrication of next‐generation rechargeable metallic lithium anodes that aims to address the intrinsic problems of metallic lithium anodes.  相似文献   

15.
    
Improving the performance of Li metal anodes is a critical bottleneck to enable next‐generation battery systems beyond Li‐ion. However, stability issues originating from undesirable electrode/electrolyte interactions and Li dendrite formation have impaired long‐term cycling of Li metal anodes. Herein, a bottom‐up fabrication process is demonstrated for a current collector for Li metal electrodeposition and dissolution composed of highly uniform vertically aligned Cu pillars. By rationally controlling geometric parameters of the 3D current collector architecture, including pillar diameter, spacing, and length, the morphology of Li plating/stripping upon cycling can be controlled and optimal cycling performance can be achieved. In addition, it is demonstrated that deposition of an ultrathin layer of ZnO by atomic layer deposition on the current collector surface can facilitate the initial Li nucleation, which dictates the morphology and reversibility of subsequent cycling. This core–shell pillar architecture allows for the effects of geometry and surface chemistry to be decoupled and individually controlled to optimize the electrode performance in a synergistic manner. Using this platform, Li metal anodes are demonstrated with Coulombic efficiency up to 99.5%, providing a pathway toward high‐efficiency and long‐cycle life Li metal batteries with reduced excess Li loading.  相似文献   

16.
    
The charge transfer kinetics between a lithium metal electrode and an inorganic solid electrolyte is of key interest to assess the rate capability of future lithium metal solid state batteries. In an in situ microelectrode study run in a scanning electron microscope, it is demonstrated that—contrary to the prevailing opinion—the intrinsic charge transfer resistance of the Li|Li6.25Al0.25La3Zr2O12 (LLZO) interface is in the order of 10?1 Ω cm2 and thus negligibly small. The corresponding high exchange current density in combination with the single ion transport mechanism (t+ ≈ 1) of the inorganic solid electrolyte enables extremely fast plating kinetics without the occurrence of transport limitations. Local plating rates in the range of several A cm?2 are demonstrated at defect free and chemically clean Li|LLZO interfaces. Practically achievable current densities are limited by lateral growth of lithium along the surface as well as electro‐chemo‐mechanical‐induced fracture of the solid electrolyte. In combination with the lithium vacancy diffusion limitation during electrodissolution, these morphological instabilities are identified as the key fundamental limitations of the lithium metal electrode for solid‐state batteries with inorganic solid electrolytes.  相似文献   

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The development of alternative anode materials with higher volumetric and gravimetric capacity allowing for fast delithiation and, even more important, lithiation is crucial for next‐generation lithium‐ion batteries. Herein, the development of a completely new active material is reported, which follows an insertion‐type lithiation mechanism, metal‐doped CeO2. Remarkably, the introduction of carefully selected dopants, herein exemplified for iron, results in an increase of the achievable capacity by more than 200%, originating from the reduction of the dopant to the metallic state and additional space for the lithium ion insertion due to a significant off‐centering of the dopant atoms in the crystal structure, away from the original Ce site. In addition to the outstanding performance of such materials in high‐power lithium‐ion full‐cells, the selective reduction of the iron dopant under preservation of the crystal structure of the host material is expected to open up a new field of research.  相似文献   

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Gel polymer-based lithium batteries exhibit a unique combination of advantageous properties, including the favorable interfacial contact characteristic of liquid-state batteries and the inherent stability of solid-state batteries. For Li–air batteries operated in the semi-open atmosphere, implementing in situ synthesized gel polymer electrolytes (GPEs) is effective in mitigating the environment-induced challenges. In this study, a dimethyl sulfoxide (DMSO)-based GPE in situ initiated by the toluene-2,4-diisocyanate (TDI) and 1,4-benzenediboronic acid (BDBA) is designed to enable the stable operation of lithium–air batteries. The integration of in situ polymerization and polyvinyl alcohol's functional group engineering not only brings benefits to the interfacial contact and electrochemical stability of the battery but also mitigates the moisture sensitivity and volatility of the DMSO electrolyte in the ambient environment. In addition, the GPE can promote the formation of a robust protection film on the lithium surface. As a result, the designed GPE makes the batteries fully leverage their outstanding cycling stability in the ambient environment (241 cycles at 500 mA g−1 and 1000 mAh g−1). Moreover, an optimized Li–air pouch cell structure incorporating the GPE achieves a boasted energy density of 757.5 Wh kg−1, providing a significant technical pathway to bring Li–O2 batteries to practical Li–air batteries.  相似文献   

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