High Performance Low-Temperature Lithium Metal Batteries Enabled by Tailored Electrolyte Solvation Structure

The electrochemical performances of lithium metal batteries are determined by the kinetics of interfacial de-solvation and ion transport, especially at low-temperature environments. Here, a novel electrolyte that easily de-solvated and conducive to interfacial film formation is designed for low-temperature lithium metal batteries. A fluorinated carboxylic ester, diethyl fluoromalonate (DEFM), and a fluorinated carbonate, fluoroethylene carbonate (FEC) are used as solvents, while high concentrated lithium bis(trifluoromethanesulfonyl)imide (LiTFSI) is served as the solute. Through tailoring the electrolyte formulation, the lithium ions in the high concentrated fluorinated carboxylic ester electrolyte are mainly combined with anions, which weakens the bonding strength of lithium ions and solvent molecules in the solvation structure, beneficial to the de-solvation process at low temperature. The fluorinated carboxylic ester (FCE) electrolyte enables the LiFePO₄ (LFP) | Li half-cell achieves a high capacity of 91.9 mAh g⁻¹ at −30 °C, with high F content in the interface. With optimized de-solvation kinetics, the LFP | Li full cell remains over 100 mAh g⁻¹ at 0 °C after cycling 100 cycles. Building new solvents with outstanding low-temperature properties and weaker solvation to match with Li metal anode, this work brings new possibilities of realizing high energy density and low temperature energy storage batteries.     

Rechargeable Lithium Metal Batteries with an In-Built Solid-State Polymer Electrolyte and a High Voltage/Loading Ni-Rich Layered Cathode

Solid-state batteries enabled by solid-state polymer electrolytes (SPEs) are under active consideration for their promise as cost-effective platforms that simultaneously support high-energy and safe electrochemical energy storage. The limited oxidative stability and poor interfacial charge transport in conventional polymer electrolytes are well known, but difficult challenges must be addressed if high-voltage intercalating cathodes are to be used in such batteries. Here, ether-based electrolytes are in situ polymerized by a ring-opening reaction in the presence of aluminum fluoride (AlF₃) to create SPEs inside LiNi_0.6Co_0.2 Mn_0.2O₂ (NCM) || Li batteries that are able to overcome both challenges. AlF₃ plays a dual role as a Lewis acid catalyst and for the building of fluoridized cathode–electrolyte interphases, protecting both the electrolyte and aluminum current collector from degradation reactions. The solid-state NCM || Li metal batteries exhibit enhanced specific capacity of 153 mAh g⁻¹ under high areal capacity of 3.0 mAh cm⁻². This work offers an important pathway toward solid-state polymer electrolytes for high-voltage solid-state batteries.     

High-Safety and High-Energy-Density Lithium Metal Batteries in a Novel Ionic-Liquid Electrolyte

Rechargeable lithium metal batteries are next generation energy storage devices with high energy density, but face challenges in achieving high energy density, high safety, and long cycle life. Here, lithium metal batteries in a novel nonflammable ionic-liquid (IL) electrolyte composed of 1-ethyl-3-methylimidazolium (EMIm) cations and high-concentration bis(fluorosulfonyl)imide (FSI) anions, with sodium bis(trifluoromethanesulfonyl)imide (NaTFSI) as a key additive are reported. The Na ion participates in the formation of hybrid passivation interphases and contributes to dendrite-free Li deposition and reversible cathode electrochemistry. The electrolyte of low viscosity allows practically useful cathode mass loading up to ≈16 mg cm⁻². Li anodes paired with lithium cobalt oxide (LiCoO₂) and lithium nickel cobalt manganese oxide (LiNi_0.8Co_0.1Mn_0.1O₂, NCM 811) cathodes exhibit 99.6–99.9% Coulombic efficiencies, high discharge voltages up to 4.4 V, high specific capacity and energy density up to ≈199 mAh g⁻¹ and ≈765 Wh kg⁻¹ respectively, with impressive cycling performances over up to 1200 cycles. Highly stable passivation interphases formed on both electrodes in the novel IL electrolyte are the key to highly reversible lithium metal batteries, especially for Li–NMC 811 full batteries.     

A Garnet-Type Solid-Electrolyte-Based Molten Lithium−Molybdenum−Iron(II) Chloride Battery with Advanced Reaction Mechanism

Solid-electrolyte-based molten-metal batteries have attracted considerable attention for grid-scale energy storage. Although ZEBRA batteries are considered one of the promising candidates, they still have the potential concern of metal particle growth and ion exchange with the β”-Al₂O₃ electrolyte. Herein, a Li_6.4La₃Zr_1.4Ta_0.6O₁₂ solid-electrolyte-based molten lithium−molybdenum−iron(II) chloride battery (denoted as Li−Mo−FeCl₂) operated at temperature of 250 °C, comprising a mixture of Fe and LiCl cathode materials, a Li anode, a garnet-type Li-ion ceramic electrolyte, and Mo additive, is designed to overcome these obstacles. Different from conventional battery reaction mechanisms, this battery revolutionarily synchronizes the reversible Fe−Mo alloying−dealloying reactions with the delithiation−lithiation processes, meaning that the porous Mo framework derived from Fe−Mo alloy simultaneously suppresses the growth of pure Fe particles. By adopting a Li anode and a Li-ion ceramic electrolyte, the corrosion problem between the cathode and the solid electrolyte is overcome. With similar battery cost ($12 kWh⁻¹), the theoretical energy density of Li−Mo−FeCl₂ battery surpasses that of a Na−FeCl₂ ZEBRA battery over 25%, to 576 Wh kg⁻¹ and 2216 Wh L⁻¹, respectively. Experimental results further prove this cell has excellent cycling performance (472 mAh g_LiCl⁻¹ after 300 cycles, 50 mg active material) and strong tolerance against the overcharge−overdischarge (3−1.6 V) and freezing−thawing (25−250 °C) incidents.     

Initiating a Reversible Aqueous Zn/Sulfur Battery through a “Liquid Film”

Sulfur cathodes have been under intensive study in various systems, such as Li/S, Na/S, Mg/S, and Al/S batteries. However, to date, Zn/S chemistry has never been reported. The first reliable aqueous Zn/polysulfide system activated by a “liquid film” comprising 4-(3-butyl-1-imidazolio)-1-butanesulfoni ionic liquid (IL) encapsulated within PEDOT:PSS. CF₃SO₃⁻ anions in the IL operating as Zn²⁺-transfer channels is reported. Moreover, the PEDOT:PSS network retains the IL, which renders Zn²⁺-transfer channels and a polysulfide cathode with enhanced structural stability. The Zn/polysulfide system delivers extraordinary capacity of 1148 mAh g⁻¹ and overwhelming energy density of 724.7 Wh kg⁻¹_cathode at 0.3 Ag⁻¹. During the discharging phase, S₆²⁻ is dominantly reduced by Zn to S²⁻ (S₆ → S²⁻). During the charging phase, these short chains are oxidized to form long-chain Zn_xLi_yS_3-6. A further optimized high-concentrated salt electrolyte is used to improve the reversibility of the battery, demonstrating an extended lifetime over 1600 cycles at 1 Ag⁻¹ with a capacity retention of 204 mAh g⁻¹. This facile approach and the superior performance of the developed aqueous Zn/S chemistry provide a new platform for sulfur-based battery and potentially solve the problems of other metal/sulfur batteries.     

Low-Temperature Fabrication of Bulk-Type All-Solid-State Lithium-Ion Battery Utilizing Nanosized Garnet Solid Electrolytes

Garnet-type Li₇La₃Zr₂O₁₂ (LLZ) materials are attracting attention as solid electrolytes (SEs) in oxide-based all-solid-state batteries (ASSBs) owing to their high ionic conductivity. Although the electrochemical stability of LLZ against Li metal is demonstrated with possible high energy density, high-temperature sintering above 1000 °C, which is required to achieve high Li-ion conductivity, results in the formation of insulating impurities at the electrode–electrolyte interfaces. Here, nanosized fine-particle samples of Ta-substituted Li_6.5La₃Zr_1.5Ta_0.5O₁₂ (LLZT) are successfully prepared at a remarkably low temperature of 400 °C utilizing an amorphous precursor oxide. The dense LLZT SE sintered by hot pressing at 500 °C shows room-temperature Li-ion conductivity of 1.03 × 10⁻⁴ S cm⁻¹ without any additives. In addition, the bulk-type NCM–graphite full battery cell fabricated with the LLZT fine particles through a hot-pressing sintering method at 550 °C exhibits a good charge–discharge performance at room temperature with the bulk-type areal discharge capacity of 0.831 mAh cm⁻². The nanosized garnet SE strategy demonstrated in this study paves the way for the formation of oxide-based ASSBs by low-temperature sintering.     

Thiol-Branched Solid Polymer Electrolyte Featuring High Strength,Toughness, and Lithium Ionic Conductivity for Lithium-Metal Batteries

Lithium-metal batteries (LMBs) with high energy densities are highly desirable for energy storage, but generally suffer from dendrite growth and side reactions in liquid electrolytes; thus the need for solid electrolytes with high mechanical strength, ionic conductivity, and compatible interface arises. Herein, a thiol-branched solid polymer electrolyte (SPE) is introduced featuring high Li⁺ conductivity (2.26 × 10⁻⁴ S cm⁻¹ at room temperature) and good mechanical strength (9.4 MPa)/toughness (≈500%), thus unblocking the tradeoff between ionic conductivity and mechanical robustness in polymer electrolytes. The SPE (denoted as M-S-PEGDA) is fabricated by covalently cross-linking metal–organic frameworks (MOFs), tetrakis (3-mercaptopropionic acid) pentaerythritol (PETMP), and poly(ethylene glycol) diacrylate (PEGDA) via multiple C S C bonds. The SPE also exhibits a high electrochemical window (>5.4 V), low interfacial impedance (<550 Ω), and impressive Li⁺ transference number (t_Li+ = 0.44). As a result, Li||Li symmetrical cells with the thiol-branched SPE displayed a high stability in a >1300 h cycling test. Moreover, a Li|M-S-PEGDA|LiFePO₄ full cell demonstrates discharge capacity of 143.7 mAh g⁻¹ and maintains 85.6% after 500 cycles at 0.5 C, displaying one of the most outstanding performances for SPEs to date.     

Molecular-Crowding Effect Mimicking Cold-Resistant Plants to Stabilize the Zinc Anode with Wider Service Temperature Range

Growth of dendrites, the low plating/stripping efficiency of Zn anodes, and the high freezing point of aqueous electrolytes hinder the practical application of aqueous Zn-ion batteries. Here, a zwitterionic osmolyte-based molecular crowding electrolyte is presented, by adding betaine (Bet, a by-product from beet plant) to the aqueous electrolyte, to solve the abovementioned problems. Substantive verification tests, density functional theory calculations, and ab initio molecular dynamics simulations consistently reveal that side reactions and growth of Zn dendrites are restrained because Bet can break Zn²⁺ solvation and regulate oriented 2D Zn²⁺ deposition. The Bet/ZnSO₄ electrolyte enables superior reversibility in a Zn–Cu half-cell to achieve a high Coulombic efficiency >99.9% for 900 cycles (≈1800 h), and dendrite-free Zn plating/stripping in Zn–Zn cells for 4235 h at 0.5 mA cm⁻² and 0.5 mAh cm⁻². Furthermore, a high concentration of Bet lowers the freezing point of the electrolyte to −92 °C via the molecular-crowding effect, which ensures the stable operation of the aqueous batteries at −30 °C. This innovative concept of such a molecular crowding electrolyte will inject new vitality into the development of multifunctional aqueous electrolytes.     

Carbonized Polymer Dots with Controllable N,O Functional Groups as Electrolyte Additives to Achieve Stable Li Metal Batteries

Electrolyte additive is an effective strategy to inhibit the uncontrolled growth of Li dendrites for lithium metal batteries (LMBs). However, most of the additives are complex synthesis and prone to decompose in cycling. Herein, in order to guide the homogeneous deposition of Li⁺, carbonized polymer dots (CPDs) as electrolyte additives are successfully designed and synthesized by microwave (M-CPDs) and hydrothermal (H-CPDs) approaches. The controllable functional groups containing N or O (especially pyridinic-N, pyrrolic-N, and carboxyl group) enable CPDs to keep stable in electrolytes for at least 3 months. Meanwhile, the clusters formed between CPDs and Li⁺ through electrostatic interaction effectively guide the uniform Li dispersion and limit the “tip effect” and dendrite formation. Moreover, as lithiophilic groups increase, the strong electrostatic interference for the solvation effect of Li⁺ in the electrolyte is formed, which induces faster Li⁺ diffusion/transfer. As expected, H-CPDs achieve the ultra-even Li⁺ transfer. The corresponding Li//LiFePO₄ full cell delivers a high capacity retention rate of 93.8% after 200 cycles, which is much higher than that of the cells without additives (61.2%) and with M-CPDs (83.7%) as additives. The strategy in this work provides a theoretical direction for CPDs as electrolyte additives used in energy storage devices.     

Lithiophilic Nanowire Guided Li Deposition in Li Metal Batteries

Lithium (Li) metal batteries (LMBs) provide superior energy densities far beyond current Li-ion batteries (LIBs) but practical applications are hindered by uncontrolled dendrite formation and the build-up of dead Li in “hostless” Li metal anodes. To circumvent these issues, we created a 3D framework of a carbon paper (CP) substrate decorated with lithiophilic nanowires (silicon (Si), germanium (Ge), and SiGe alloy NWs) that provides a robust host for efficient stripping/plating of Li metal. The lithiophilic Li₂₂Si₅, Li₂₂(Si_0.5Ge_0.5)_5, and Li₂₂Ge₅ formed during rapid Li melt infiltration prevented the formation of dead Li and dendrites. Li₂₂Ge₅/Li covered CP hosts delivered the best performance, with the lowest overpotentials of 40 mV (three times lower than pristine Li) when cycled at 1 mA cm⁻²/1 mAh cm⁻² for 1000 h and at 3 mA cm⁻²/3 mAh cm⁻² for 500 h. Ex situ analysis confirmed the ability of the lithiophilic Li₂₂Ge₅ decorated samples to facilitate uniform Li deposition. When paired with sulfur, LiFePO_4, and NMC811 cathodes, the CP-LiGe/Li anodes delivered 200 cycles with 82%, 93%, and 90% capacity retention, respectively. The discovery of the highly stable, lithiophilic NW decorated CP hosts is a promising route toward stable cycling LMBs and provides a new design motif for hosted Li metal anodes.     

Medium-Entropy-Alloy FeCoNi Enables Lithium–Sulfur Batteries with Superb Low-Temperature Performance

Lithium-sulfur battery suffers from sluggish kinetics at low temperatures, resulting in serious polarization and reduced capacity. Here, this work introduces medium-entropy-alloy FeCoNi as catalysts and carbon nanofibers (CNFs) as hosts. FeCoNi nanoparticles are in suit synthesized in cotton-derived CNFs. FeCoNi with atomic-level mixing of each element can effectively modulate lithium polysulfides (LiPSs), multiple components making them promising to catalyze more LiPSs species. The higher configurational entropy endows FeCoNi@CNFs with extraordinary electrochemical activity, corrosion resistance, and mechanical properties. The fractal structure of CNFs provides a large specific surface area, leaving room for volume expansion and Li₂S accumulation, facilitating electrolyte wetting. The unique 3D conductive network structure can suppress the shuttle effect by physicochemical adsorption of LiPSs. This work systematically evaluates the performance of the obtained Li₂S₆/FeCoNi@CNFs electrode. The initial discharge capacity of Li₂S₆/FeCoNi@CNFs reaches 1670.8 mAh g⁻¹ at 0.1 C under -20 °C. After 100 cycles at 0.2 C, the capacity decreases from 1462.3 to 1250.1 mAh g⁻¹. Notably, even under -40 °C at 0.1 C, the initial discharge capacity of Li₂S₆/FeCoNi@CNFs still reaches 1202.8 mAh g⁻¹. After 100 cycles at 0.2 C, the capacity retention rate is 50%. This work has important implications for the development of low-temperature Li-S batteries.     

Modulating Ionic Transport and Interface Chemistry via Surface-Modified Silica Carrier in Nano Colloid Electrolyte for Stable Cycling of Li-Metal Batteries

Tailoring the Li⁺ microenvironment is crucial for achieving fast ionic transfer and a mechanically reinforced solid–electrolyte interphase (SEI), which administers the stable cycling of Li-metal batteries (LMBs). Apart from traditional salt/solvent compositional tuning, this study presents the simultaneous modulation of Li⁺ transport and SEI chemistry using a citric acid (CA)-modified silica-based colloidal electrolyte (C-SCE). CA-tethered silica (CA-SiO₂) can render more active sites for attracting complex anions, leading to further dissociation of Li⁺ from the anions, resulting in a high Li⁺ transference number (≈0.75). Intermolecular hydrogen bonds between solvent molecules and CA-SiO₂ and their migration also act as nano-carrier for delivering additives and anions toward the Li surface, reinforcing the SEI via the co-implantation of SiO₂ and fluorinated components. Notably, C-SCE demonstrated Li dendrite suppression and improved cycling stability of LMBs compared with the CA-free SiO₂ colloidal electrolyte, hinting that the surface properties of the nanoparticles have a huge impact on the dendrite-inhibiting role of nano colloidal electrolytes.     

Converting Nafion into Li+-Conductive Nanoporous Materials

Sulfonated polymers have long been used as proton-conducting materials in fuel cells, and their ionic transport features are highly attractive for electrolytes in lithium-ion/metal batteries (LIBs/LMBs). However, most studies are still based on a preconceived notion of using them directly as polymeric ionic carriers, which precludes exploring them as nanoporous media to construct efficient lithium ions (Li⁺) transport network. Here, effective Li⁺-conducting channels realized by swelling nanofibrous Nafion is demonstrated, which is a classical sulfonated polymer in fuel cells. The sulfonic acid groups, interact with LIBs liquid electrolytes to form porous ionic matrix of Nafion and assist partial desolvation of Li⁺-solvates to further enhance Li⁺ transport. Li-symmetric cells and Li-metal full cells (Li₄Ti₅O₁₂ or high-voltage LiNi_0.6Co_0.2Mn_0.2O₂ as a cathode) with such membrane show excellent cycling performance and stabilized Li-metal anode. The finding provides a strategy to convert the vast sulfonated polymer family into efficient Li⁺ electrolyte, promoting the development of high-energy–density LMBs.     

In Situ Designing a Gradient Li+ Capture and Quasi-Spontaneous Diffusion Anode Protection Layer toward Long-Life Li−O2 Batteries

Lithium metal is the only anode material that can enable the Li−O₂ battery to realize its high theoretical energy density (≈3500 Wh kg⁻¹). However, the inherent uncontrolled dendrite growth and serious corrosion limitations of lithium metal anodes make it experience fast degradation and impede the practical application of Li−O₂ batteries. Herein, a multifunctional complementary LiF/F-doped carbon gradient protection layer on a lithium metal anode by one-step in situ reaction of molten Li with poly(tetrafluoroethylene) (PTFE) is developed. The abundant strong polar C-F bonds in the upper carbon can not only act as Li⁺ capture site to pre-uniform Li⁺ flux but also regulate the electron configuration of LiF to make Li⁺ quasi-spontaneously diffuse from carbon to LiF surface, avoiding the strong Li⁺-adhesion-induced Li aggregation. For LiF, it can behave as fast Li⁺ conductor and homogenize the nucleation sites on lithium, as well as ensure firm connection with lithium. As a result, this well-designed protection layer endows the Li metal anode with dendrite-free plating/stripping and anticorrosion behavior both in ether-based and carbonate ester-based electrolytes. Even applied protected Li anodes in Li−O₂ batteries, its superiority can still be maintained, making the cell achieve stable cycling performance (180 cycles).     

Stabilizing ultrahigh-nickel layered oxide cathodes for high-voltage lithium metal batteries

Rechargeable lithium (Li) metal batteries (LMBs) with ultrahigh-nickel (Ni) layered oxide cathodes offer a great opportunity for applications in electrical vehicles. However, increasing Ni content inherently arouses a tradeoff between specific capacity and electrochemical cyclability due to the aggressive side reactions with electrolyte contributed by the highly reactive Ni species. Here, a protective and stable cathode/electrolyte interphase featuring enriched and evenly-distributed LiF is in situ formed on ultrahigh-Ni cathode LiNi_0.94Co_0.06O₂ (NC) with an advanced ether-based localized high-concentration electrolyte (LHCE), which concurrently shows good compatibility with Li metal anode. Subsequently, the NC cathode can deliver high capacity retentions of 81.4% after 500 cycles at 25 °C and 91.6% after 100 cycles at 60 °C in the voltage range of 2.8–4.4 V in Li||NC cells at 1C cycling rate (1.5 mA cm⁻²). Meanwhile, the conductive electrode/electrolyte interphases formed in LHCE enable a high reversible capacity of about 209 mAh g⁻¹ at 3C charging rate. This work provides an effective approach and important insight from the perspective of in situ ultrahigh-Ni cathode/electrolyte interphase protection for high energy–density, long-lasting LMBs.     

High-Energy Aqueous Magnesium Ion Batteries with Capacity-Compensation Evolved from Dynamic Copper Ion Redox

The low specific capacity and low voltage plateau are significant challenges in the advancement of practical magnesium ion batteries (MIBs). Here, a superior aqueous electrolyte combining with a copper foam interlayer between anode and separator is proposed to address these drawbacks. Notably, with the dynamic redox of copper ions, the weakened solvation of Mg²⁺ cations in the electrolyte and the enhanced electronic conductivity of anode, which may offer effective capacity-compensation to the 3,4,9,10-perylenetetracarboxylic diimide (PTCDI)-Mg conversion reactions during the long-term cycles. As a result, the unique MIBs using expanded graphite cathode coupled with PTCDI anode demonstrate exceptional performance with an ultra-high capacity (205 mAh g⁻¹, 243 Wh kg⁻¹ at 5 A g⁻¹) as well as excellent cycling stability after 600 cycles and rate capability (138 mAh g⁻¹, 81 Wh kg⁻¹ at 10 A g⁻¹).     

Tape-Casting Li0.34La0.56TiO3 Ceramic Electrolyte Films Permit High Energy Density of Lithium-Metal Batteries

Ceramic oxide electrolytes are outstanding due to their excellent thermostability, wide electrochemical stable windows, superior Li-ion conductivity, and high elastic modulus compared to other electrolytes. To achieve high energy density, all-solid-state batteries require thin solid-state electrolytes that are dozens of micrometers thick due to the high density of ceramic electrolytes. Perovskite-type Li_0.34La_0.56TiO₃ (LLTO) freestanding ceramic electrolyte film with a thickness of 25 µm is prepared by tape-casting. Compared to a thick electrolyte (>200 µm) obtained by cold-pressing, the total Li ionic conductivity of this LLTO film improves from 9.6 × 10⁻⁶ to 2.0 × 10⁻⁵ S cm⁻¹. In addition, the LLTO film with a thickness of 25 µm exhibits a flexural strength of 264 MPa. An all-solid-state Li-metal battery assembled with a 41 µm thick LLTO exhibits an initial discharge capacity of 145 mAh g⁻¹ and a high capacity retention ratio of 86.2% after 50 cycles. Reducing the thickness of oxide ceramic electrolytes is crucial to reduce the resistance of electrolytes and improve the energy density of Li-metal batteries.     

Spontaneous Desaturation of the Solvation Sheath for High-Performance Anti-Freezing Zinc-Ion Gel-Electrolyte

In recent years, gel-electrolyte becomes pivotal in preventing hydrogen evolution, reducing dendrite growth, and protecting the zinc metal anode for zinc-ion batteries. Herein, a polyvinyl alcohol-based water–organic hybrid gel electrolyte with Agar and dimethyl sulfoxide is designed to construct the spontaneous desaturation of the solvation sheath for reducing hydrogen evolution and dendrite growth at room temperature and even low temperature. According to experimental characterization and theoretical calculations, the well binding between multihydroxy polymer and H₂O is achieved in the hybrid desaturated gel-electrolyte to regulate the inner and outer sheath. The ionic conductivity of hybrid gel-electrolyte reaches 7.4 mS cm⁻¹ even at −20 °C with only 0.5 m zinc trifluoromethanesulfonate (Zn(OTf)₂). The Zn symmetric cells cycle over 1200 h under 26 and −20 °C with improved mechanical properties and electrochemical performance. The asymmetric Zn || Cu cell with hybrid gel electrolyte reaches ≈99.02% efficiency after 250 cycles. The capacity of full cell is maintained at around 74 mAh g⁻¹ with almost unchanged retention rate from 50 to 300 cycles at −20 °C. This work provides an effective strategy for desaturated solvation to reach anti-freezing and high-density Zn energy storage devices.     

Mass-Producible,Quasi-Zero-Strain,Lattice-Water-Rich Inorganic Open-Frameworks for Ultrafast-Charging and Long-Cycling Zinc-Ion Batteries

Low-cost and high-safety aqueous Zn-ion batteries are an exceptionally compelling technology for grid-scale energy storage. However, their development has been plagued by the lack of stable cathode materials allowing fast Zn²⁺-ion insertion and scalable synthesis. Here, a lattice-water-rich, inorganic-open-framework (IOF) phosphovanadate cathode, which is mass-producible and delivers high capacity (228 mAh g⁻¹) and energy density (193.8 Wh kg⁻¹ or 513 Wh L⁻¹), is reported. The abundant lattice waters functioning as a “charge shield” enable a low Zn²⁺-migration energy barrier, (0.66 eV) even close to that of Li⁺ within LiFePO₄. This fast intrinsic ion-diffusion kinetics, together with nanostructure effect, allow the achievements of ultrafast charging (71% state of charge in 1.9 min) and an ultrahigh power density (7200 W kg⁻¹ at 107 Wh kg⁻¹). Equally important, the IOF exhibits a quasi-zero-strain feature (<1% lattice change upon (de)zincation), which ensures ultrahigh cycling durability (3000 cycles) and Coulombic efficiencies of 100%. The cell-level energy and power densities reach ≈90 Wh kg⁻¹ and ≈3320 W kg⁻¹, far surpassing commercial lead–acid, Ni–Cd, and Ni–MH batteries. Lattice-water-rich IOFs may open up new opportunities for exploring stable and fast-charging Zn-ion batteries.     

In Situ Construction of a LiF-Enriched Interface for Stable All-Solid-State Batteries and its Origin Revealed by Cryo-TEM

The application of solid polymer electrolytes (SPEs) is still inherently limited by the unstable lithium (Li)/electrolyte interface, despite the advantages of security, flexibility, and workability of SPEs. Herein, the Li/electrolyte interface is modified by introducing Li₂S additive to harvest stable all-solid-state lithium metal batteries (LMBs). Cryo-transmission electron microscopy (cryo-TEM) results demonstrate a mosaic interface between poly(ethylene oxide) (PEO) electrolytes and Li metal anodes, in which abundant crystalline grains of Li, Li₂O, LiOH, and Li₂CO₃ are randomly distributed. Besides, cryo-TEM visualization, combined with molecular dynamics simulations, reveals that the introduction of Li₂S accelerates the decomposition of N(CF₃SO₂)₂⁻ and consequently promotes the formation of abundant LiF nanocrystals in the Li/PEO interface. The generated LiF is further verified to inhibit the breakage of C O bonds in the polymer chains and prevents the continuous interface reaction between Li and PEO. Therefore, the all-solid-state LMBs with the LiF-enriched interface exhibit improved cycling capability and stability in a cell configuration with an ultralong lifespan over 1800 h. This work is believed to open up a new avenue for rational design of high-performance all-solid-state LMBs.