Sodium Dendrite Growth Research Articles

A multifunctional separator as sustained release Carrier of NaNO3 to Address the low solubility of Nitrate in Electrolyte

In the face of modern large-scale energy storage needs, sodium metal batteries (SMBs) with high energy density have received widespread attention. However, safety and cycle stability issues have become obstacles to the practical application of SMBs. In this paper, we present a multifunctional and high-performance SMBs separator (NNP91) utilizing the nonwoven composite NaNO3@PVDF. NNP91 has good tensile properties and offers possibilities for flexible batteries. In addition, NNP91 has a dense separator layer that can physically block sodium dendrites to prevent short-circuit of the cell. More importantly, NNP91 brings NaNO3 into the cell, which is insoluble in conventional electrolytes. NaNO3 and Na metal form a nitride-rich solid electrolyte interphase (SEI) that inhibits the disordered growth of sodium dendrites, increases the rate of ionic shuttling and exhibits excellent electrochemical performance. NNP91 offers a new approach to inorganic materials insoluble in electrolytes.

A Novel Super-Toughness and Self-Healing Solid Polymer Electrolyte for Solid Sodium Metal Batteries.

Solid sodium metal batteries (SSMBs) offer an alternative promising power source for electrochemical energy storage due to their high energy density and high safety. However, the inherent sodium dendrite growth and poor mechanical properties of electrolytes seriously limit their application. Herein, a network structure composed of polyethylene oxide-based composite polymer electrolyte (CPE) is designed with liquid metal nanoparticles (LM) for SSMBs, in which LM can move in the solid electrolyte with the electric field driven. This effect can facilitate the inactivated sodium return to the metal sodium anode, and alloy with dendrites at the same time, which is beneficial for inhibiting the growth of dendrites. The symmetric cell with the CPE containing LM achieves good cyclic stability of more than 1800 and 800h at 0.1 and 0.2mAcm-2, respectively. The energy density of the pouch battery can reach 230Whkg-1. In sum, LM presents great potential to be employed as a performance reinforcement filler for CPEs, which paves the way for achieving high-performance SSMBs.

Fluorinated solid electrolyte interphase enables interfacial stability for sulfide-based solid-state sodium metal batteries

Sulfide solid electrolytes (SSEs) with high ionic conductivity and good mechanical flexibility are considered ideal for all-solid-state sodium metal batteries (ASSSMBs). Nevertheless, the detrimental interfacial issue between SSEs and Na metal presents a significant challenge for sulfide-based ASSSMBs. Herein, we demonstrate a facile and cost-effective method for constructing a controllable NaF-rich artificial interphase on the surface of sodium metal anodes by incorporating perfluoropolyether (PFPE). A stratified solid electrolyte interphase (SEI) composed a nanocrystalline NaF inner phase and organic outer shell, efficaciously seals the Na surface. The interfacial interactions between SSEs and Na metal is explored using Comsol and ab initio molecular dynamics simulations, revealing that the presence of a NaF-rich artificial interphase hinders the growth of sodium dendrites and mitigates the decomposition of the sulfide electrolytes. As a result, the symmetric cell exhibits stable Na plating/stripping cycling for 800 h at 0.1 mA cm−2. Overall, our PFPE-modified sodium metal anodes offer a promising avenue for the widespread application of high-performance ASSSMBs.

Heterostructured fluoride-based solid electrolytes engineered by grain boundary softening and bonding for sustainable Na metal batteries

Fluoride solid electrolytes stand out as promising candidates for high-energy-density solid-state batteries owing to their inherent structural and air stability. However, their application in sodium based batteries has been hindered by their low ionic conductivity. Here, we propose a heterostructured fluoride-based solid electrolyte engineered by grain boundary softening and bonding for sustainable Na metal batteries. By leveraging a low-melting-point chloride eutectic mixture NaCl-1.1AlCl3 (NA), we achieve the in situ activation of sodium ion transport at the grain boundaries of Na3GaF6 (NGF), with the formation of a molten salt interphase primarily composed of NaAlCl4. This process effectively softens the edges of NGF and heals the intergranular voids. The NA decorated NGF electrolyte exhibits the significantly enhanced ionic conductivities of 2.7 × 10–4 S/cm at 60 °C and 2.45 × 10–5 S/cm at room temperature, representing two orders of magnitude improvement over pure NGF. The chloride shell does not degrade the wide electrochemical window and air stability of NGF. This electrolyte relies on a unique "self-protection" mechanism when cycling with sodium metal anode. The molten salt phase can evolve into a compact NaCl protective shell and an Na-Al conductive inner layer with tight contact with Na anode. This dual-layer structure mitigates the side reaction with NGF host, homogenizes the current flow, and suppresses the growth of sodium dendrites. The corresponding Na//Na symmetric cells display the small voltage polarization and stable cycling performance for over 1000 h. The solid-state Na//FeF3 batteries deliver a high capacity of 308 mAh/g and sustain for at least 100 cycles with high capacity retention based on conversion reaction.

A robust 3D nanostructured composite polymer electrolyte with novel dual-ion channels toward solid-state sodium metal batteries

The high energy density and low cost of sodium metal batteries enable them to be the rising star of next-generation batteries. However, the growth of sodium dendrites and the high activity of sodium metal may lead to significant safety risks for liquid sodium metal batteries. Composite polymer electrolytes (CPEs), which combine the advantages of inorganic solid-state electrolyte and solid-state polymer electrolytes, have become a promising candidate to replace liquid electrolytes. In this study, a novel Na-beta-Al2O3/polyacrylonitrile (PAN) CPE with a 3D network nanostructure (NAP) has been synthesized by electrospinning method. NAP membrane provides synergistic dual-ion channels for the migration of sodium ions, exhibiting ionic conductivity of 7.22 × 10−4 S cm−1, a sodium-ion transport number of 0.73, and an electrochemical stabilization window as high as 4.92 V. Compared with pure PAN, NAP presents enhanced mechanical strength, superior electrochemical properties and interfacial stability. NAP-based sodium symmetric cell achieves stable plating and stripping for 800 h. At room temperature, the capacity retention ratios of NAP-based Na3V2(PO4)3//Na cell are 92.02% (0.2 C, 200 cycles) and 73.10% (0.5 C, 1000 cycles), respectively. The capacity retention is 72.49% after 250 cycles at 0.5 C and a high temperature of 60 °C. X-ray photoelectron spectroscopy spectra indicate that solid electrolyte interphase formed in NAP-based battery contains higher NaF component, R–(CO)O–Na content and interfacially favorable organic components, which are beneficial to accelerate the sodium-ion transfer at the interface. This work provides new insights into the construction of 3D nanostructured CPEs with fast ion transport for solid-state sodium metal batteries.

Synergistic Regulation of Sodium Metal Deposition Pattern Through Three-Dimensional Sodiophilic Gradient ZnO/Fe0.7Co0.3 Frameworks and Magnetic Fields for High-Performance Sodium Metal Batteries.

The application of sodium metal battery is hampered by the large volume change and uncontrollable top growth of Na metal. Herein, a dual strategy including constructing a three-dimensional gradient ZnO/Fe0.7Co0.3 (ZFC) framework of decreasing sodiophilic capability from bottom to top, and imposing magnetic fields based on magnetohydrodynamic (MHD) effect, is proposed to regulate the sodium deposition/stripping behavior and realize the bottom-up deposition of Na. Therefore, the ZFC framework under a magnetic field of 200 mT exhibits high electrochemical reversibility with a Coulombic efficiency of 99.77 % at 1 mA cm-2 and 1 mAh cm-2. Meanwhile, the ZFC composite anode (ZFC@Na) with the magnetic field of 200 mT delivers a small polarization voltage of approximately10 mV and long cycle life of more than 2500 h at 5 mA cm-2 and 5 mAh cm-2 in symmetric cells, along with good cycle stability in ZFC@Na||Na3V2(PO4)3 full cells (200 cycles at 1 C with a high capacity retention of 98 %). Accordingly, the novel strategy of combining magnetic fields and sodiophilic gradient frameworks provides a perspective to solve the issues of sodium dendrite growth.

High Modulus Na2SiO3‐Rich Solid Electrolyte Interphase Enable Long‐Cycle and Energy‐Dense Sodium Metal Battery

AbstractSodium metal battery is considered as one of the most promising energy storage/conversion devices due to their high energy density, and abundant sodium reserves. However, its development is hampered by the limited metallic utilization and detrimental sodium dendrite growth ascribed to the unstable, and fragile solid electrolyte interphase (SEI). Here, the high stable and modulus SEI is constructed with a component of a thin and dense layer of high Na‐ion conductive Na2SiO3. It is in situ formed by the reaction between sodium anode and fish‐skin structure separator, which exhibits a 3D porous polyvinylidene fluoride‐based framework embedded with thin and robust vermiculite sheets. The robust interphase cannot only suppress sodium dendrite growth but also enable high energy density with small interphase‐consumed Na ions in anode‐less batteries. Accordingly, the as‐assembled NaNi1/3Fe1/3Mn1/3O2//Na cell shows 83% capacity retention after 5000 cycles at a rate of 5 °C. Moreover, the proof‐of‐concept pouch cells deliver an energy density of 205 Wh kg−1 (based on the total mass of the battery), and high safety (not catching fire after punctured) under anode‐less condition (with a low negative/positive capacity ratio of ≈2.1).

NaBix/NaVyOz Hybrid Interfacial Layer Enables Stable and Dendrite-Free Sodium Anodes.

The challenges of sodium metal anodes, including formation of an unstable solid-electrolyte interphase (SEI) and uncontrolled growth of sodium dendrites during charge-discharge cycles, impact the stability and safety of sodium metal batteries. Motivated by the promising commercialization potential of sodium metal batteries, it becomes imperative to systematically explore innovative protective interlayers specifically tailored for sodium metal anodes. In this work, a NaBix/NaVyOz hybrid and porous interfacial layer on sodium anode is successfully fabricated via pretreating sodium with bismuth vanadate. The hybrid interlayer effectively combines the advantages of sodium vanadates and alloys, raising a synergistic effect in facilitating sodium deposition kinetics and inhibiting the growth of sodium dendrites. As a result, the modified sodium electrodes (BVO-Na) can stably cycle for 2000h at 0.5mAcm-2 with a fixed capacity of 1mAhcm-2, and the BVO-Na||Na3V2(PO4)3 full cell sustains a high capacity of 94 mAh g-1 after 600 cycles at 5C. This work demonstrates that constructing an artificial hybrid interlayer is a practical solution to obtain high performance anodes in sodium metal batteries.

Three-dimensional ZnO/CC coupled with external magnetic field for controlled sodium deposition

Abstract Sodium-metal batteries are garnering increasing attention due to their utilization of abundant resources and high theoretical specific capacity. However, the growth of sodium dendrites has remained a challenging issue, which makes it difficult to apply. In this study, we employ carbon cloth as a substrate to mitigate the sodium dendrite growth, onto which sodium-affinitive material ZnO is grown to facilitate uniform nucleation. Furthermore, we enhance the cycling stability and rate performance significantly by introducing an external magnetic field. Under a 200 mT applied magnetic field and deposition/stripping at 1 mA/cm2 and 1 mAh/cm2, symmetric cells exhibit a remarkable cycling stability exceeding 1200 hours. Additionally, in full cells, NVP is used for the positive electrode, and ZnO/CC is the negative electrode, with a capacity of 108 mAh/g, and energy density maintained at 429.4 Wh/kg over 200 cycles under the influence of a 200 mT magnetic field.

Crafting high‐performance polymer‐integrated solid electrolyte for solid state sodium ion batteries

AbstractThe development of modern solid‐state batteries with high energy density has provided the reliable and durable solution needed for over‐the‐air network connectivity devices. In this study, a NASICON‐type Na3Zr2Si2PO12 (NZSP) ceramic filler was prepared using the sol‐gel method and then a polymer‐integrated solid electrolyte consisting of polyethylene oxide (PEO), NZSP, and sodium perborate (SPB) was prepared by Stokes' solution casting process. Through physico‐chemical and electrochemical characterization techniques, the morphology, electrochemical, and thermal properties of the prepared solid electrolyte sample were carefully studied. The PEO/NZSP/SPB electrolyte developed for all‐solid‐state sodium‐ion batteries (ASSSBs) exhibited a strong ionic conductivity, a large window for electrochemical stability, and was effective in controlling the growth of sodium dendrites. Furthermore, the polymer‐integrated solid electrolyte showed impressive rate capability, high discharge capacity (73.2 mAh g−1) at 0.1 mA cm−2, and good faradaic efficiency (98%) even after 100 cycles. These results reveal that the PEO/NZSP/SPB electrolyte is a potential and inevitable candidate for the evolution of high‐performance rechargeable ASSSBs.

1,3,6-Hexanetricarbonitrile as electrolyte additive to inhibit sodium dendrites in sodium-metal batteries

Sodium-metal batteries (SMBs) offer substantial competitiveness owing to their wide elemental distribution and high specific capacity. However, SMBs face safety issues such as unstable properties of the Solid Electrolyte Interphase (SEI) layer due to irregular sodium dendrites. In this paper, we constructed a stable and uniform SEI layer by introducing the 1,3,6-Hexanetricarbonitrile (HTCN) electrolyte additive, replacing the conventional, insoluble nitrate. HTCN facilitates the generation of substances like Na3N with high electrical conductivity on the Na anode surface. This accelerates Na+ shuttling and provides high-flux nucleation sites. Molecular dynamics simulations were employed to elucidate the solvated structure of electrolyte and radial distribution of Na+ after HTCN addition. Moreover, in-situ optical microscopy revealed a stable and robust SEI layer, effectively inhibiting the disorderly growth of sodium dendrites. The superior cycling performance of the Na3V2(PO4)3 (NVP)/Na full cell further demonstrates the addition of HTCN.

Calcium Doped NASICON Electrolyte with Graphite Coating for Stable All-solid-state Sodium Metal Batteries.

All-solid-state sodium metal batteries face the challenges of low ionic conductivity of solid electrolytes and poor wettability towards metallic Na anode. Herein, Na3Zr2Si2PO12 solid electrolyte is doped with Ca2+, obtaining a high ionic conductivity of 2.09×10-3 S cm-1 with low electronic conductivity of 1.43×10-8 S cm-1 at room temperature, which could accelerate Na+ transportation and suppress sodium dendrite growth. Meanwhile, a graphite-based interface layer is coated on Na3.4Zr1.8Ca0.2Si2PO12 (Na3.4Zr1.8Ca0.2Si2PO12-G) in order to improve the solid-solid contact between solid electrolyte and Na anode, realizing a uniform current distribution and smooth Na metal plating/stripping, and thus achieving a triple higher critical current density of 3.5 mA cm-2 compared with that of Na3.4Zr1.8Ca0.2Si2PO12. In addition, the assembled Na3V2(PO4)3/Na3.4Zr1.8Ca0.2Si2PO12-G/Na all-solid-state battery exhibits excellent electrochemical performances with a reversible capacity of 81.47 mAh g-1 at 1 C and capacity retention of 97.75 % after 500 cycles.

Sodium Difluoro(oxalato)borate Additive‐Induced Robust SEI and CEI Layers Enable Dendrite‐Free and Long‐Cycling Sodium‐Ion Batteries

AbstractSodium‐ion batteries (SIBs) are a promising candidate for large‐scale energy storage due to the low cost and abundant sodium resources. However, the formation of sodium dendrites on the surface of hard carbon (HC) anodes is the most intractable challenge for full cells during charging, leading to severe performance degradation and safety hazards. Here, a robust additive‐induced borate and fluoride‐rich interphase is constructed by introducing sodium difluoro(oxalato)borate (NaDFOB) as additive in the ether‐based electrolyte to relieve the performance deterioration for SIBs. NaDFOB can participate in the passivation process of electrolyte‐electrode interfaces through preferential oxidation and reduction of DFOB− to effectively restrain the growth of sodium dendrites. Moreover, the electrolyte decomposition and dissolution of transition metal ions are effectively inhibited. Benefiting from that, FeMn‐based Prussian blue (FeMnHCF) || HC full cell with a negative/positive capacity ratio (N/P ratio) of 1.09 displays a capacity retention of 82.1%, especially with a low N/P ratio of 0.96 the cell still demonstrates a stable Coulombic efficiency of over 99.9% after 500 cycles via using NaDFOB as additive. As a practical demonstration, the designed 18650 full cells display enhanced cycling stability with NaDFOB additive. The findings provide insights into the additive‐induced inorganic‐rich interfacial layers for dendrite‐free SIBs.

A High-Rate and Long-Life Sodium Metal Battery Based on a NaB3H8 ⋅ xNH3@NaB3H8 Composite Solid-State Electrolyte.

All-solid-state sodium metal batteries are promising for large-scale energy storage applications owing to their intrinsic safety and cost-effectiveness. However, they generally suffer from sodium dendrite growth or rapid capacity fading, especially at high rates, mainly due to poor wettability, sluggish ionic transport, or low interfacial stability of the solid electrolytes. Herein, we report a novel composite, NaB3H8 ⋅ xNH3@NaB3H8 (x<1), as a new class of solid electrolyte for high-rate batteries. NaB3H8 ⋅ xNH3@NaB3H8 is obtained from the sticky NaB3H8 ⋅ NH3 after removal of NH3 partially at room temperature. It delivers an ionic conductivity of 0.84 mS cm-1 at 25 °C and reaches 20.64 mS cm-1 at 45 °C after an order-disorder phase transformation. It also reveals a good capability of dendrite suppression and remarkable stability against sodium metal. These performances enable the all-solid-state Na//TiS2 battery with a high capacity of 232.4 mAh g-1 (97.2 % of theoretical capacity) and long-term cycling stability at 1 C. Notably, this battery shows superior long-life cycling stability even at 5 and 10 C, which has been rarely reported in all-solid-state sodium metal batteries. This work opens a new group of solid electrolytes, contributing to fast-charging or high-power-density sodium metal batteries.

A High‐Rate and Long‐Life Sodium Metal Battery Based on a NaB3H8 ⋅ xNH3@NaB3H8 Composite Solid‐State Electrolyte

AbstractAll‐solid‐state sodium metal batteries are promising for large‐scale energy storage applications owing to their intrinsic safety and cost‐effectiveness. However, they generally suffer from sodium dendrite growth or rapid capacity fading, especially at high rates, mainly due to poor wettability, sluggish ionic transport, or low interfacial stability of the solid electrolytes. Herein, we report a novel composite, NaB3H8 ⋅ xNH3@NaB3H8 (x&lt;1), as a new class of solid electrolyte for high‐rate batteries. NaB3H8 ⋅ xNH3@NaB3H8 is obtained from the sticky NaB3H8 ⋅ NH3 after removal of NH3 partially at room temperature. It delivers an ionic conductivity of 0.84 mS cm−1 at 25 °C and reaches 20.64 mS cm−1 at 45 °C after an order‐disorder phase transformation. It also reveals a good capability of dendrite suppression and remarkable stability against sodium metal. These performances enable the all‐solid‐state Na//TiS2 battery with a high capacity of 232.4 mAh g−1 (97.2 % of theoretical capacity) and long‐term cycling stability at 1 C. Notably, this battery shows superior long‐life cycling stability even at 5 and 10 C, which has been rarely reported in all‐solid‐state sodium metal batteries. This work opens a new group of solid electrolytes, contributing to fast‐charging or high‐power‐density sodium metal batteries.

Stable sodium-metal batteries with a hierarchical structured electrode toward reversible confinement of Na dendrites

Sodium metal is a promising candidate for the future of rechargeable batteries. However, a significant problem, that is, the growth of sodium dendrites, which are uncontrolled microscopic structures that reduce battery performance and stability, remains unaddressed. To resolve this issue, the development of three-dimensional (3D) nanostructured hosts to prevent dendrite growth and cease the buildup of inactive sodium has been proposed. However, research on developing an uncomplicated process to design these 3D hosts is currently lacking. In this study, we used the ice-templating method to form a self-supporting 3D hierarchical porous structure using a graphene oxide dispersion. This approach offers significant benefits in terms of scalability and cost-effectiveness. The resulting porous design offers numerous nucleation sites, which in turn reduce the intensity of local electric fields around dendrites and lower the current density. Consequently, sodium ions are deposited more evenly, which helps inhibit dendrite growth. Our test results indicated stable cycling performance, with 250, 200, and 150 cycles achieved for deposition volumes of 0.25, 0.5, and 1.0 mAh cm−2, respectively, at a constant current density of 0.25 mA cm−2. By utilizing in situ optical cell analysis, we observed the effective suppression of dendrite growth. Furthermore, ex situ examination confirmed the absence of dendrite formation, even at a high deposition capacity of 5.0 mAh cm−2. These results underline the potential of using a 3D hierarchical porous structure to effectively improve the performance and longevity of sodium-metal batteries.

Construction of an ultra-stable mixed conductive layer to stabilize the solid-state electrolyte/Na interface by in-situ interface chemistry

The quest for high energy density, essentially safe, and cost-effective energy storing systems is powering the evolution of solid-state sodium metal batteries (SSSMBs). However, insufficient Na/solid-state electrolyte (SSE) interface contact leads to the formation of sodium dendrites, causing premature cell failure and safety issues that limit their practical application. Here, a novel ultra-stable mixed conductive layer (MCL) composed of Na15Sn4 and NaF is introduced at the Na|Na3Zr2Si2PO12 (NZSP) interface through in-situ interface chemistry. Such an MCL not only enables the transformation of the NZSP surface from sodiophobic to sodiophilic to achieve intimate contact with Na but also homogenizes the Na+ flux without dendritic sodium. Benefiting from the construction of the multifunctional interface, a high critical current density (CCD) of 1.3 mA cm−2 and an exceptionally long cycle life of 6000 h at 0.3 mA cm−2 are achieved for the Na|SnF2@NZSP|Na cell at room temperature (RT). Furthermore, the Na|SnF2@NZSP|Na3V2(PO4)3 full cell shows excellent cycling performance (91 % of maintained capacity for over 500 cycles at 1 C) and rate capability (101.4 mAh/g at 5 C) at RT. This work presents a validated method for the coordinated regulation of interfacial transfer kinetics and inhibition of sodium dendrite growth.

In-Situ Alloy-Modified Sodiophilic Current Collectors for Anode-Less Sodium Metal Batteries

Anode-less sodium metal batteries have drawn dramatica attention owing to their high specific energy and low cost. However, the growth of sodium dendrites and the resulting loss of active materials and serious safety concerns hinder their practical applications. In this work, a bismuth-based modification layer with good sodiophilicity is constructed on the surface of Cu foil (denoted as Cu@Bi) to control the deposition of Na metal. The activation-derived porous Na-rich alloy phase can provide abundant nucleation sites and reduce the nucleation overpotential to induce the uniform and dense deposition of Na metal. When evaluated in half cell, the Cu@Bi current collectors can operate for 750 h at 1 mA cm−2 and 1 mAh cm−2, with an average coulombic efficiency (CE) of 99.5%. When the current density is improved to 2 mA cm−2, the Cu@Bi can also stably maintain for 750 cycles, demonstrating the remarkable effect of the modification layer. When coupled with the Na3V2(PO4)3 cathode, the full cell exhibits stable cycle performance over 80 cycles. The modification strategy of alloy modification can provide fresh ideas for the research and application of anode-less and even anode-free metal batteries.

Novel organic molecule enabling a highly-stable and reversible sodium metal anode for room-temperature sodium-metal batteries

The cycle life of sodium metal batteries is hampered primarily by the unwarranted growth of sodium dendrites and their low Coulombic efficiency. Electrolyte additives can extend the cycle life by modifying the local interfacial electrochemistry of the metal anodes. Nevertheless, a high overpotential for deposition impeded the stripping/plating stability. We present 9-Fluorenone (9F), a novel electrolyte additive for highly stable and reversible sodium metal batteries. Even at a high current density of 20 mA cm−2, sodium deposition occurs seamlessly with this electrolyte additive. According to thermochemistry calculations, 9F molecules modulate the breakdown barrier and shield sodium-ion solvation shells from further decomposition, limiting the loss of metal anode and electrolyte inventory. As a result, a reversible stripping/plating of sodium can be accomplished for over 1200 h with a minimal overpotential of 25 mV. By combining metal sulfide cathodes, sodium metal anodes with ether-based electrolyte, and 9F additive molecules, we demonstrate the feasibility of developing a stable and long-lasting sodium‑sulfur battery that operates at room temperature and last >300 cycles.

Flame-retardant electrolyte enables sodium metal batteries to limit dendrites and stabilize cycling

While sodium metal batteries (SMBs) have received much notice because of their low cost and abundant resources, they also suffer from an uncontrollable growth of dendritic crystals during the charging/discharging processes. This paper reports using Hexafluorocyclotriphosphazene (HFPN) as a flame-retardant additive and film-forming additive for SMBs mixed with conventional NaPF6 in a carbonate-based electrolyte. (1) the self-extinguishing time of the electrolyte was tested and the flame retardant mechanism of the flame retardant additive was explained; (2) the growth of sodium dendrites in the symmetric cell during constant current charging and discharging was observed using in situ optical microscopy; (3) the stable formation of HFPN with solid electrolyte interface (SEI) was illustrated by Scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS) characterization, and the excellent cycling performance of the sodium metal all-cell with Na3V2(PO4)3 as the positive electrode was demonstrated.