Towards All-Solid-State Polymer Batteries: Going Beyond PEO with Hybrid Concepts

To go beyond polyethylene oxide in lithium metal batteries, a hybrid polymer/oligomer cell design is presented, where an ester oligomer provides high ionic conductivity of 0.2 mS cm⁻¹ at 40 °C within thicker composite cathodes with active mass loadings of up to 11 mg cm⁻² (LiNbO₃-coated) LiNi_0.6Mn_0.2Co_0.2 (NMC622), while a 30 µm thin scaffold-supported polymer electrolyte affords mechanical stability. Corresponding discharge capacities of the hybrid cells exceed 170 mAh g⁻¹ (11 mg cm⁻²) or 160 mAh g⁻¹ (6 mg cm⁻²) at rates of either 0.1 or 0.25 C. Multilayer pouch cells are projected to enable energy densities of 235 Wh L⁻¹ (6 mg cm⁻²) and even up to 356 Wh L⁻¹ (11 mg cm⁻²), clearly superior to other reported polymer-based cell designs. Polyester electrolytes are environmentally benign and safer compared to common liquid electrolytes, while the straightforward synthesis and affordability of precursors render hybrid polyester electrolytes suitable candidates for future application in solid-state lithium metal batteries.     

An Efficient Bifunctional Air Electrode for Reversible Protonic Ceramic Electrochemical Cells

One of the main bottlenecks that limit the performance of reversible protonic ceramic electrochemical cells (R-PCECs) is the sluggish kinetics of the oxygen reduction and evolution reactions (ORR and OER). Here, the significantly enhanced ORR and OER kinetics and stability of a conventional La_0.6Sr_0.4Co_0.2Fe_0.8O_3–δ (LSCF) air electrode by an efficient catalyst coating of barium cobaltite (BCO) is reported. The polarization resistance of a BCO-coated LSCF air electrode at 600 ° C is 0.16  Ω  cm², about 30% of that of the bare LSCF air electrode under the same conditions. Further, an R-PCEC with the BCO-coated LSCF air electrode shows exceptional performance in both fuel cell (peak power density of 1.16 W cm⁻² at 600 ° C) and electrolysis (current density of 1.80 A cm⁻² at 600 ° C at 1.3 V) modes. The performance enhancement is attributed mainly to the facilitated rate of oxygen surface exchange.     

In Situ Engineering of a Cobalt-free Perovskite Air Electrode Enabling Efficient Reversible Oxygen Reduction/Evolution Reactions

Reversible protonic ceramic electrochemical cells (R-PCECs) have received increasing focus for their good capability of converting and storing energy. However, the widely used cobalt-based air electrodes are less thermomechanically compatible with the electrolyte and lack stability, which largely limits the development of R-PCECs. Herein, a cobalt-free perovskite with a nominal composition of PrBa_0.8Ca_0.2Fe_1.8Ce_0.2O_6δ (PBCFC) is reported, which is in–situ engineered to a (Ba, Ce) deficient-PBCFC phase, a BaCeO₃, and a CeO₂ phase under typical operating conditions, delivering a low area–specific resistance of 0.10 Ωcm² at 700 ^oC. The generated BaCeO₃ and CeO₂ particles increase the conduction/transfer of protons and oxygen ions, thus providing extra active sites for the oxygen reactions. When utilized as an air electrode on a single cell, it achieves encouraging performance at 700 °C: a peak power density of 1.78 Wcm⁻² and a current density of 5.00 Acm⁻² at 1.3 V in the dual mode of the fuel cell (FC) and electrolysis (EL) mode with reasonable Faradaic efficiencies. In addition, the cells exhibit favorable operational durability of 65 h (FC mode), 95 h (EL mode), and promising cycling stability of 200 h.     

Enabling High-Performance NASICON-Based Solid-State Lithium Metal Batteries Towards Practical Conditions

Solid-state lithium metal batteries (SSLMBs) are promising next-generation high-energy rechargeable batteries. However, the practical energy densities of the reported SSLMBs have been significantly overstated due to the use of thick solid-state electrolytes, thick lithium (Li) anodes, and thin cathodes. Here, a high-performance NASICON-based SSLMB using a thin (60 µm) Li_1.5Al_0.5Ge_1.5(PO₄)₃ (LAGP) electrolyte, ultrathin (36 µm) Li metal, and high-loading (8 mg cm⁻²) LiFePO₄ (LFP) cathode is reported. The thin and dense LAGP electrolyte prepared by hot-pressing exhibits a high Li ionic conductivity of 1 × 10⁻³ S cm⁻¹ at 80 °C. The assembled SSLMB can thus deliver an increased areal capacity of ≈1 mAh cm⁻² at C/5 with a high capacity retention of ≈96% after 50 cycles under 80 °C. Furthermore, it is revealed by synchrotron X-ray absorption spectroscopy and in situ high-energy X-ray diffraction that the side reactions between LAGP electrolyte and LFP cathode are significantly suppressed, while rational surface protection is required for Ni-rich layered cathodes. This study provides valuable insights and guidelines for the development of high-energy SSLMBs towards practical conditions.     

Smart Construction of an Intimate Lithium | Garnet Interface for All-Solid-State Batteries by Tuning the Tension of Molten Lithium

All-solid-state lithium batteries (ASSBs) have the potential to trigger a battery revolution for electric vehicles due to their advantages in safety and energy density. Screening of various possible solid electrolytes for ASSBs has revealed that garnet electrolytes are promising due to their high ionic conductivity and superior (electro)chemical stabilities. However, a major challenge of garnet electrolytes is poor contact with Li-metal anodes, resulting in an extremely large interfacial impedance and severe Li dendrite propagation. Herein, an innovative surface tension modification method is proposed to create an intimate Li | garnet interface by tuning molten Li with a trace amount of Si₃N₄ (1 wt%). The resultant Li-Si-N melt can not only convert the Li | garnet interface from point-to-point contact to consecutive face-to-face contact but also homogenize the electric-field distribution during the Li stripping/depositing process, thereby significantly decreasing its interfacial impedance (1 Ω cm² at 25 °C) and improving its cycle stability (1000 h at 0.4 mA cm⁻²) and critical current density (1.8 mA cm⁻²). Specifically, the all-solid-state full cell paired with a LiFePO₄ cathode delivered a high capacity of 145 mAh g⁻¹ at 2 C and maintained 97% of the initial capacity after 100 cycles at 1 C.     

Grafting of Lithiophilic and Electron-Blocking Interlayer for Garnet-Based Solid-State Li Metal Batteries via One-Step Anhydrous Poly-Phosphoric Acid Post-Treatment

Garnet-based solid-state Li-metal batteries (GSSBs) have the merits of high energy density and high safety. However, the realization of a stable and well-matched Li|garnet interface for GSSBs remains challenging due to electron leakage and lithiophobic Li₂CO₃ impurity. To address these issues, herein, new surface chemistry is reported that converts the undesired Li₂CO₃ contaminant into an ultra-thin lithium polyphosphate (Li-PPA) layer through anhydrous polyphosphoric acid -induced in situ substitution reaction without damaging the water-sensitive garnet electrolyte. In particular, the Li-PPA interlayer not only facilitates the homogenous spreading of molten Li but also creates a robust electron-blocking shield to suppress Li dendrite formation. As a result, the assembled Li symmetric cell exhibits a low interfacial impedance (4 Ω cm²) and high critical current density (1.8 mA cm⁻²) at 25 °C, which enables the cell to continuously cycle over 2500 h at 0.2 mA cm⁻². Furthermore, the GSSBs paired with LiFePO₄ deliver a high capacity of 149.3 mAh g⁻¹ at 1 C and maintain 92.3% of the initial capacity after 500 cycles and can be used for solar energy storage, suggesting the feasibility of this interfacial engineering strategy for GSSBs.     

In-Built Quasi-Solid-State Poly-Ether Electrolytes Enabling Stable Cycling of High-Voltage and Wide-Temperature Li Metal Batteries

Developing solid-state electrolytes with good compatibility for high-voltage cathodes and reliable operation of batteries over a wide-temperature-range are two bottleneck requirements for practical applications of solid-state metal batteries (SSMBs). Here, an in situ quasi solid-state poly-ether electrolyte (SPEE) with a nano-hierarchical design is reported. A solid-eutectic electrolyte is employed on the cathode surface to achieve highly-stable performance in thermodynamic and electrochemical aspects. This performance is mainly due to an improved compatibility in the electrode/electrolyte interface by nano-hierarchical SPEE and a reinforced interface stability, resulting in superb-cyclic stability in Li || Li symmetric batteries ( > 4000 h at 1 mA cm⁻²/1 mAh cm⁻²; > 2000 h at 1 mA cm⁻²/4 mAh cm⁻²), which are the same for Na, K, and Zn batteries. The SPEE enables outstanding cycle-stability for wide-temperature operation (15–100 ° C) and 4 V-above batteries (Li || LiCoO₂ and Li || LiNi_0.8Co_0.1Mn_0.1O₂). The work paves the way for development of practical SSMBs that meet the demands for wide-temperature applicability, high-energy density, long lifespan, and mass production.     

SnF2-Induced Highly Current-Tolerant Solid Electrolytes for Solid-State Sodium Batteries

Solid-state sodium batteries have garnered considerable interest. However, their electrochemical performance is hampered by severe interfacial resistance between sodium metal and inorganic solid electrolytes, as well as Na dendrite growth within the electrolytes. To address these issues, a uniform and compact SnF₂ film is first introduced onto the surface of the inorganic solid electrolyte Na_3.2Zr_1.9Ca_0.1Si₂PO₁₂ (NCZSP) to improve contact through an effective and straightforward process. Through experiments and computations, the in situ conversion reaction between SnF₂ and molten Na is adequately confirmed, resulting in a composite conductive layer containing Na_xSn alloys and NaF at the interface. As a result, the interfacial resistance of Na/NCZSP is significantly decreased from 813 to 5 Ω cm², and the critical current density is dramatically increased to 1.8 mA cm⁻², as opposed to 0.2 mA cm⁻² with bare NCZSP. The symmetric cell is able to cycle stably at 0.2 mA cm⁻² for 1300 h at 30 °C and exhibits excellent current tolerance of 0.3 and 0.5 mA cm⁻². Moreover, the Na₃V₂(PO₄)₃/SnF₂-NCZSP/Na full cell displays excellent rate performance and cycling stability. The SnF₂-induced interlayer proves significant in improving interfacial contact and restraining sodium dendrite propagation, thus promoting the development of solid-state sodium batteries.     

High Ionic Conductivity Motivated by Multiple Ion-Transport Channels in 2D MOF-Based Lithium Solid State Battery

Metal-organic frameworks (MOFs) have been proposed as novel fillers for constructing polymer solid electrolytes based composite electrolytes. However, MOFs are generally used as passive fillers, in-depth revealing the binding mode between MOFs and polyethylene oxide (PEO), the critical role of MOFs in facilitating Li⁺ transport in solid electrolytes is full of challenges. Herein, inspired by density functional theory (DFT) the 2D-MOF with rich unsaturated metal coordination sites that can bind the O atom in PEO through the metal–oxygen bond,  anchor TFSI⁻ to release Li⁺, resulting in a remarkable Li⁺ transference number of 0.58, is reported according well with the experimental results and molecular dynamics (MD) simulation. Impressively, after the introduction of the 2D-MOF, the Li⁺ can rapidly hop along the benzene ring center within the 2D-MOF plane, and the interface between the benzene ring and PEO can also serve as a fast Li⁺ migration pathway, delivering multiple ion-transport channels, which present a high ion conductivity of 4.6 × 10⁻⁵ S cm⁻¹ (25 °C). The lithium symmetric battery is stable for 1300 h at 60 °C, 0.1 mA cm⁻². The assembled lithium metal solid state battery maintains high capacity of 162.8 mAh g⁻¹ after 500 cycles at 60 °C and 0.5 C. This multiple ion-transport channels approach brings new ideas for designing advanced solid electrolytes.     

Robust Biocatalysts Displayed on Crystalline Protein-Layered Cells for Efficient and Sustainable Hydration of Carbon Dioxide

Mineral carbonation is the most effective carbon capture technique, but carbon dioxide (CO₂) conversion is limited by the slow hydration rate of CO₂ (<10⁻¹ s⁻¹). A biological solution exists: carbonic anhydrase (CA) efficiently hydrates CO₂ at a turnover rate of ≈10⁶ s⁻¹ under ambient conditions, making it an extremely attractive candidate for industrial post-combustion CO₂ capture. However, high cost and poor long-term stability impose a technical barrier to its practical uses. Here, a genetically engineered Corynebacterium glutamicum (C. glutamicum) is introduced as a robust cell display platform for the in situ stabilization and low-cost production of CA. The enzyme is displayed in the mycolic layer with porin B as an anchoring protein with (GGGGS)₂ as a spacer. The cell-displayed CA exhibits no significant inactivation of the CO₂ hydration activity for at least one month at 37 °C. Its denaturation rate constant at 50 °C (0.07) is an order of magnitude lower than that of free CA (0.52–0.54). This study demonstrates that a structurally robust cell template allows the effective stabilization of CA, suggesting the C. glutamicum-based cell display as a promising technique to achieve highly efficient, sustainable, and low-cost CO₂ capture for industrial applications.     

Glassy Metal–Organic-Framework-Based Quasi-Solid-State Electrolyte for High-Performance Lithium-Metal Batteries

Enhancing ionic conductivity of quasi-solid-state electrolytes (QSSEs) is one of the top priorities, while conventional metal–organic frameworks (MOFs) severely impede ion migration due to their abundant grain boundaries. Herein, ZIF-4 glass, a subset of MOFs, is reported as QSSEs (LGZ) for lithium-metal batteries. With lean Li content (0.12 wt%) and solvent amount (19.4 wt%), LGZ can achieve a remarkable ion conductivity of 1.61 × 10⁻⁴ S cm⁻¹ at 30 °C, higher than those of crystalline ZIF-4-based QSSEs (LCZ, 8.21 × 10⁻⁵ S cm⁻¹) and the reported QSSEs containing high Li contents (0.32–5.4 wt%) and huge plasticizer (30–70 wt%). Even at −56.6 °C, LGZ can still deliver a conductivity of 5.96 × 10⁻⁶ S cm⁻¹ (vs 4.51 × 10⁻⁷ S cm⁻¹ for LCZ). Owing to the grain boundary-free and isotropic properties of glassy ZIF-4, the facilitated ion conduction enables a homogeneous ion flux, suppressing Li dendrites. When paired with LiFePO₄ cathode, LGZ cell demonstrates a prominent cycling capacity of 101 mAh g⁻¹ for 500 cycles at 1 C with the near-utility retention, outperforming LCZ (30.7 mAh g⁻¹) and the explored MOF-/covalent–organic frameworks (COF)-based QSSEs. Hence, MOF glasses will be a potential platform for practical quasi-solid-state batteries in the future.     

Regulating Na-ion Solvation in Quasi-Solid Electrolyte to Stabilize Na Metal Anode

Sodium metal batteries are promising for cost-effective energy storage, however, the sluggish ion transport in electrolytes and detrimental sodium-dendrite growth stall their practical applications. Herein, a cross-linking quasi-solid electrolyte with a high ionic conductivity of 1.4 mS cm⁻¹ at 25 °C is developed by in-situ polymerizing poly (ethylene glycol) diacrylate-based monomer. Benefiting from the refined solvation structure of Na⁺ with a much lower desolvation barrier, random Na⁺ diffusion on the Na surface is restrained, so that the Na dendrite formation is suppressed. Consequently, symmetrical Na||Na cells employing the electrolyte can be cycled >2000 h at 0.1 mA cm⁻². Na₃V₂(PO₄)₃||Na batteries reveal a high discharge specific capacity of 66.1 mAh g⁻¹ at 15 C and demonstrate stable cycling over 1000 cycles with a capacity retention of 83% at a fast rate of 5 C.     

Porphyrin Helical Nanochannel-Assembled Polybenzimidazole Membranes Doped with Phosphoric Acid for Fuel Cells Operating in a Temperature Range of 25–200 °C

High-temperature proton-exchange membrane fuel cells (HT-PEMFCs) fabricated with phosphoric acid (PA)-doped polybenzimidazole (PBI) show apparent technical advantages. In practical automotive applications, achieving cold start-up capability is crucial. In this work, a kind of branched block proton exchange membrane (PEM) based on PBI with a low content of porphyrin ring (<1 mol.%) is reported as a branched monomer. Self-assembly into high-density helical nanochannels under the synergistic effect of phase separation and porphyrin π−π stacking, thus the PEM can maintain a high level of PA doping. Specifically, the PA/1.8TCPP-BrPy-OPBI membrane shows a proton conductivity of 0.169 and 0.071 S cm⁻¹, as well as an H₂-O₂ fuel cell peak power density of 1077 and 357 mW cm⁻² at 180 and 80 °C without humidification and backpressure, respectively. The membrane electrode assembly (MEA) can exhibit good fuel cell stability, with a voltage decay rate of only 7.0 µV h⁻¹ at 80 °C. Furthermore, it maintains a peak power density of 93% even after 150 start-up/shut-down cycles at 25 °C. This work expands the operating temperature range of conventional PBI membranes between 25 and 200 °C and thus provides a novel strategy for high-performance PBI-based HT-PEMFCs.     

Salty Ice Electrolyte with Superior Ionic Conductivity Towards Low-Temperature Aqueous Zinc Ion Hybrid Capacitors

Aqueous electrochemical energy storage (EES) devices have attracted considerable attention due to their advantages of low cost and high safety. However, the freeze of aqueous electrolytes usually causes the dramatic loss of ionic conduction capacity, thereby seriously restricting the low-temperature application of such EES devices. Herein, different from traditional frozen electrolytes, a Zn(ClO₄)₂ salty ice with superior ionic conductivity (1.3 × 10⁻³ S cm⁻¹ even at −60 °C) is discovered. It is attributed to the unique 3D ionic transport channels inside such ice, which enables the fast transport of both Zn²⁺ ions and ClO₄⁻ ions inside the ice at low temperatures. Using this Zn(ClO₄)₂ salty ice as an electrolyte, as-built zinc ion hybrid capacitor is able to work even at −60 °C (with 74.2% of the room temperature capacity), and exhibits an ultra-long cycle life of 70 000 cycles at low temperature. This discovery provides a new insight for constructing low-temperature EES devices using salty ices as electrolytes.     

Enhancing Oxygen Reduction Activity and Cr Tolerance of Solid Oxide Fuel Cell Cathodes by a Multiphase Catalyst Coating

Intermediate temperature solid oxide fuel cells (IT-SOFCs) are cost-effective and efficient energy conversion systems. The sluggish oxygen reduction reaction (ORR) and the degradation of cathodes are critical challenges to the commercialization of IT-SOFCs. Here, a highly efficient multiphase (MP) catalyst coating, consisting of Ba_1−xCo_0.7Fe_0.2Nb_0.1O_3−δ (BCFN) and BaCO₃, to enhance the ORR activity and durability of the state-of-the-art lanthanum strontium cobalt ferrite (La_0.6Sr_0.4Co_0.2Fe_0.8O_3−δ, LSCF) cathode is reported. The conformal MP catalyst-coated LSCF cathode shows a polarization resistance (R_p) of 0.048 Ω cm² at 650 °C, about one order of magnitude smaller than that of the bare LSCF. In an accelerated Cr-poisoning test, the degradation rate of the catalyst-coated LSCF electrode is 10⁻³ Ω cm² h⁻¹ (0.59% h⁻¹) over 200 h, only one fifth of the degradation rate of the bare LSCF electrode at 750 °C. In addition, anode-supported single cells with the MP catalyst-coated LSCF cathode show a dramatically enhanced peak power density (1.4 W cm⁻² vs 0.67 W cm⁻² at 750 °C) and increased durability against Cr and H₂O. Both experimental results and density functional theory-based calculations indicate that the BCFN phase improves the ORR activity while the BaCO₃ phase enhances the stability of the LSCF cathode.     

Analysis of the Annealing Budget of Metal Oxide Thin-Film Transistors Prepared by an Aqueous Blade-Coating Process

Metal oxide (MO) semiconductors are widely used in electronic devices due to their high optical transmittance and promising electrical performance. This work describes the advancement toward an eco-friendly, streamlined method for preparing thin-film transistors (TFTs) via a pure water-solution blade-coating process with focus on a low thermal budget. Low temperature and rapid annealing of triple-coated indium oxide thin-film transistors (3C-TFTs) and indium oxide/zinc oxide/indium oxide thin-film transistors (IZI-TFTs) on a 300 nm SiO₂ gate dielectric at 300 °C for only 60 s yields devices with an average field effect mobility of 10.7 and 13.8 cm² V⁻¹ s⁻¹, respectively. The devices show an excellent on/off ratio (>10⁶), and a threshold voltage close to 0 V when measured in air. Flexible MO-TFTs on polyimide substrates with AlO_x dielectrics fabricated by rapid annealing treatment can achieve a remarkable mobility of over 10 cm² V⁻¹ s⁻¹ at low operating voltage. When using a longer post-coating annealing period of 20 min, high-performance 3C-TFTs (over 18 cm² V⁻¹ s⁻¹) and IZI-TFTs (over 38 cm² V⁻¹ s⁻¹) using MO semiconductor layers annealed at 300 °C are achieved.     

Highly Reversible Zinc-Air Batteries at −40 °C Enabled by Anion-Mediated Biomimetic Fat

The wide application of portable electrical equipment, aerial vehicles, smart robotics, etc. has boosted the development of advanced batteries with safety, high energy density, and environmental adaptability. Inspired by the fat layer on animal bodies, biomimetic fat is constructed as electrolytes of solid-state zinc-air batteries to achieve excellent cycling performance at low temperatures. Via tailored anion-H₂O interaction, the antifreezing gel electrolytes, with the multi-performance of interface compatibility, temperature adaptability, and stable power supply simultaneously, build robust Zn|electrolyte interface, thus promoting uniform interfacial electric fields and Zn deposition. Excellent long-term cyclability of 120 h at a high current density of 50 mA cm⁻² are exhibited at 25 °C. Moreover, at −40 °C, a record-long cycling life of 205 h at a current density as large as 10 mA cm⁻² is achieved.     

Solvent-Free Electrolyte for High-Temperature Rechargeable Lithium Metal Batteries

The formation of lithiophobic inorganic solid electrolyte interphase (SEI) on Li anode and cathode electrolyte interphase (CEI) on the cathode is beneficial for high-voltage Li metal batteries. However, in most liquid electrolytes, the decomposition of organic solvents inevitably forms organic components in the SEI and CEI. In addition, organic solvents often pose substantial safety risks due to their high volatility and flammability. Herein, an organic-solvent-free eutectic electrolyte based on low-melting alkali perfluorinated-sulfonimide salts is reported. The exclusive anion reduction on Li anode surface results in an inorganic, LiF-rich SEI with high capability to suppress Li dendrite, as evidenced by the high Li plating/stripping CE of 99.4% at 0.5  mA cm⁻² and 1.0 mAh cm⁻², and 200-cycle lifespan of full LiNi_0.8Co_0.15Al_0.05O₂ (2.0 mAh cm⁻²) || Li (20 µm) cells at 80 °C. The proposed eutectic electrolyte is promising for ultrasafe and high-energy Li metal batteries.     

Nonpolar Cosolvent Driving LUMO Energy Evolution of Methyl Acetate Electrolyte to Afford Lithium-Ion Batteries Operating at −60 °C

The operation of lithium-ion batteries (LIBs) at low temperatures (<−20 °C) is hindered by the low conductivity and high viscosity of conventional carbonate electrolytes. Methyl acetate (MA) has proven to be a competitive low-temperature electrolyte solvent with low viscosity and low freezing point, but its interfacial stability is poor and remains elusive until now. Here, it is revealed thaat the reductive stability of MA-based electrolytes is fundamentally governed by the anion-prevailed solvation structure. Based on this framework, fluorobenzene is employed in the electrolyte to promote the entry of anions into the solvation shell via dipole-dipole interactions and the generation of free MA, thus enhancing the lowest unoccupied molecular orbital energy of MA. The designed electrolyte enables LiCoO₂ (LCO)/graphite cells to exhibit excellent cycling performance at −20 °C (90% retention after 1000 cycles at 1 C) and to remain 91% of their room-temperature capacity at a super-low temperature of −60 °C at 0.05 C. Thanks to the plentiful free MA, this electrolyte has a high conductivity (2.61 mS cm⁻¹) at −60 °C and allows LCO/graphite cell to charge at −60 °C. This study offers the possibility of practical applications for those solvents with poor reductive stability and provides new approaches to designing advanced electrolytes for low-temperature applications.     

Boosting the Na-Ion Conductivity in the Cluster-Ion Based Anti-Perovskite Na2BH4NH2

Solid-state sodium-ion/metal batteries (SSSBs) are highly desirable for next-generation energy storage systems, while very limited Na-ion solid-state electrolytes are explored. The borohydride-based solid electrolytes are expected to achieve the high energy density target, due to their low redox potential, low Young's modulus as well as high stability toward alkali metals. However, the biggest challenge of borohydride-based electrolyte is the low ionic conductivity. In this study, an anti-perovskite solid-state electrolyte (SSE) material rich in vacancy defects is explored, Na₂BH₄NH₂, to solve above problems. Benefitting from rich vacancy defects, a high ionic conductivity of 7.56 × 10⁻⁴ S cm⁻¹ with a low activation energy for Na⁺ migration of 0.67 eV at 90 °C are achieved. The NaSn|Na₂BH₄NH₂|NaSn symmetric cell cycles at a current density of 0.1 mA cm⁻² for 500 h. Moreover, the universality of Na₂BH₄NH₂ electrolyte is verified by TiS₂ cathode, indicating that Na₂BH₄NH₂ has good compatibility with electrode material. These outstanding performances suggest that it is a viable strategy to increase the ionic conductivity by forming vacancy defects, leading to the further development of solid electrolytes with superior properties.