Symmetric Cell Research Articles

Nucleophilic Sn Seeding and Interface Engineering for Highly Stable Sodium Metal Batteries.

Sodium metal is a promising anode material for energy storage beyond lithium-ion batteries due to its abundance and low cost. However, the uncontrolled growth of dendrites and associated safety concerns have limited the practical application of sodium metal batteries (SMBs). By embedding nucleophilic tin seeds in a free-standing carbon film (FSF), here, an effective solution is developed to stabilize the sodium metal anode. The highly conductive and porous carbon matrix, intimately embedded with abundant Sn seeds (C@Sn), enables remarkably uniform sodium plating, and provides long-term stability for SMBs. Mechanistic studies confirm the formation of an Na─Sn alloy on interface which helps to lower the nucleation barrier for sodium plating. Hence, symmetric sodium cells equipped with C@Sn FSFs can sustain uninterrupted sodium plating and stripping for almost 2600h at a high areal capacity of 4mAhcm-2, achieving an average Coulombic efficiency (CE) of 99.88%. In addition, full cells prepared with commercial Na3V2(PO4)3 cathode and C@Sn-FSFs anode deliver remarkable cycling (90mAhg-1 beyond 1300 cycles at 1C) and excellent rate performance. This ingenious strategy of embedding Sn particles within a carbon matrix offers an overall compelling solution to enhance the longevity of sodium anodes.

A Multifunctional Na2Se/Zn-Mn Skeleton Enables Processable and Highly Reversible Sodium Metal Anode.

The recent high-energy density sodium (Na) metal batteries (SMBs) are restricted by their processability, lifetime, and safety. These issues can be addressed by controlling the reactions at the Na metal by modifying the Na metal anode (SMA) with the sodiophilic hosts. Herein, a multifunctional Na2Se/Zn-Mn skeleton is introduced for SMA and fabricate a processable Na@Na2Se/Zn-Mn composite using repeated cold rolling/folding approach through the spontaneous reaction between Na metal and ZnMnSe alloy. This unique intermetallic composite has Zn and Mn metal sites for uniform deposition of Na, while Na2Se generates a stable SEI for rapid Na+ ion transport. It offers outstanding sodiophilicity, high processability, excellent mechanical strength, and high ionic conductivity due to the synergistic effect of multi-component, enabling stable Na plating/stripping at high current densities and areal capacities. An optimized Na2Se/Zn-Mn skeleton enables Na||Na symmetric cells to attain a high critical current density of 5.0mA cm-2 at 5.0 mAh cm-2 with an extended lifespan of 9000h at 1.0mA cm-2 at 1.0 mAh cm-2. Remarkably, when configured into a full cell with a Na3V2(PO4)3 cathode, the SMB displays an extended lifespan of 2000 cycles at 10 C and an impressive high-rate capacity of ≈61.6 mAh g-¹ at 30 C.

Constructing High‐Performance Zn‐Iodine Batteries with CuI‐PVP Composite Layer Coated Zn Anodes

AbstractAqueous zinc‐iodine (Zn‐I2) batteries featuring abundant raw materials, inherent safety, excellent cost competitiveness and environmental benignity have been identified as one kind of important electrochemical energy storage devices. However, these batteries always suffer from inferior electrochemical performance, because of dendrite growth and corrosion/passivation of the anodes. Herein, a copper iodide‐polyvinylpyrrolidone (CuI‐PVP) composite layer is proposed to suppress the parasitic reactions and protect the Zn anodes. In this layer, the CuI can spontaneously react with metallic Zn and convert into Cu and Cu5Zn8 (2CuI+Zn→2Cu+ZnI2; 5Cu+8Zn→Cu5Zn8). The highly zincophilic Cu and Cu5Zn8, as heterogeneous seeds, can guide the uniform Zn nucleation and deposition, while alleviating corrosion of the Zn anodes. At the same time, the iodide species releasing from the composite layer can be oxidized and deposited on the cathodes, contributing additional capacity. As a result, the symmetric cell prepared with the CuI‐PVP@Zn anodes demonstrates a long cycling lifetime of 1400 hours at 1 mA cm−2 and 1 mAh cm−2. Under an even higher current density of 5 mA cm−2, the CuI‐PVP@Zn cell can still stably work for more than 660 hours. The practical application of this CuI‐PVP@Zn electrode has been further demonstrated in Zn‐I2 full batteries, which achieve 60 % higher specific capacity than the untreated ones (251.4 vs. 157.1 mAh g−1 after 2800 cycles).

Concurrent Regulation of Surface Topography and Interfacial Physicochemistry via Trace Chelation Acid Additives toward Durable Zn Anodes

AbstractElectrolyte additive engineering is a feasible protocol in improving Zn anode stability. Typical additive designs center on the regulation of Zn deposition; nevertheless, versatile additives are urgently requested to comprehensively manage the surface landscape, interface physicochemistry, and by‐product elimination. Here, a straightforward strategy is presented to meet such needs employing an environmentally‐friendly chelator, hydroxyethyl‐ethylenediaminetriacetate acid (HEDTA), as an additive for ZnSO4 electrolyte. Throughout theoretical computations and experimental investigations, it is demonstrated that protons released from the gradual ionization of HEDTA during rest periods aid in the mild engraving of the Zn surface. Both the amino and carboxyl groups of HEDTA⁻ can be protonated, which effectively buffers the interfacial pH value in the entire battery lifespan and eliminates the formation of by‐products. The HEDTA− anions can also adsorb onto the Zn surface, helping facilitate Zn2⁺ mass transfer and accelerate the desolvation process. Benefiting from the synchronous modulation of surface topography and interfacial physicochemistry, the assembled half cells affording HEDTA additive maintain a durable operation of up to 8821 cycles at 5.0 mA cm−2/1.0 mAh cm−2. Additionally, symmetric cells manifest stable cycling for over 4600 h at 0.5 mA cm−2/0.25 mAh cm−2.

Synergistic Long-Term Protection of Inorganic and Polymer Hybrid Coatings for Free-Dendrite Zinc Anodes.

Constructing an artificial solid electrolyte interface protective layer on the surface of the zinc anode is an effective strategy for addressing dendrite growth, passivation, and the hydrogen evolution reaction in aqueous zinc-ion batteries. This study introduces a robust interlayer composed of a polyvinyl butyral matrix decorated with SiO2 particles (PS). Adsorption of water by Si-OH on the surface of SiO2 leads to excellent hydrophilicity and accelerates the desolvation of ions. A highly stable and hydrophilic PS coating enhances ion migration and possesses ultralong protection ability, ensuring uniform ion deposition and a lower nucleation barrier. Anodes protected by the PS coating achieve long-term cycling stability of >4000 h at 2 mA cm-2 in symmetric cells. The assembled PS-Zn//NH4V4O10 full cells exhibit superior electrochemical performance, demonstrating their potential for practical applications in rechargeable zinc batteries.

Multifunctional Amphoteric Additive Alanine Enables High-Performance Wide-pH Zn Metal Anodes.

Interfacial pH fluctuation is one of the primary reasons for issues related to Zn metal anodes. Herein, polar amphoteric alanine, as a multifunctional electrolyte additive, is designed to regulate the electric double layer (EDL) and solvation structure. Alanine with self-adaptation capability to pH can stabilize electrolyte pH. Due to more negative adsorption energy, alanine preferentially adsorbs on the Zn surface and repels water molecules within the EDL. Alanine-enriched EDL effectively shields the surface tips, homogenizes interfacial electric field distribution, and promotes preferential deposition of horizontal flaky Zn. Alanine-enriched EDL limits the contact between water and the Zn anode. Alanine additive decreases the quantity of water molecules in the Zn2+ solvation sheath and disrupts H-bond networks in the electrolyte. Consequently, a dense and textured Zn deposition is achieved. Corrosion and side reactions are suppressed. Cycling stability of symmetrical cells attains 2700h at 3mAcm-2/1mAhcm-2 and 2050h at 5mAcm-2/1mAhcm-2. Average coulombic efficiency reaches 99.8% over 4500 cycles at 5mAcm-2/1mAhcm-2. Even within KOH alkaline electrolytes, alanine additive still improves the cycling lifespan of symmetrical cells to 100h at 0.5mAcm-2/0.5mAhcm-2.

Constructing a Multifunctional SEI Layer Enhancing Kinetics and Stabilizing Zinc Metal Anode

AbstractZn dendrite growth and parasitic reactions at the interface of zinc anode/electrolyte in aqueous zinc batteries severely hinder its lifespan in application. Herein, the zinc anode is effectively stabilized by introducing trace amounts of 4‐aminobutane‐1‐phosphate (ABPA) into the ZnSO4 electrolyte. The ABPA adsorbs onto the surface of zinc anode and then further decomposes to a high conductive organic/inorganic composite in situ SEI layer including amino, partial carbon chain, and zinc phosphate. In the SEI layer, the residual undecomposed carbon chain promotes the desolvation of Zn2+, the amino induces uniform Zn2+ plating and zinc phosphate facilitates the migration of Zn2+. Thus, this in situ SEI layer not only suppresses water‐related side reactions but also enhances the Zn2+ transport kinetics. As a result, Zn||Zn symmetric cell delivers an ultralong cycle life of over 13 000 cycles at 50 mA cm−2 and 1 mAh cm−2. A high average Coulombic efficiency of 99.72% is achieved in over 1000 cycles in Zn||Cu half‐cell. The Zn||I2 full cell delivers a high‐capacity retention of 91.42% after 40,000 cycles. Moreover, a 49 mAh Zn||I2 pouch cell maintains 80.28% capacity retention over 300 cycles and 61.22% after 1000 cycles.

Ultra‐Tough Dynamic Supramolecular Ion‐Conducting Elastomer Induced Uniform Li+ Transport and Stabilizes Interphase Ensures Dendrite‐Free Lithium Metal Anodes

AbstractArtificial polymer solid electrolyte interphases (SEIs) with microphase‐separated structures provide promising solutions to the inhomogeneity and cracking issues of natural SEIs in lithium metal batteries (LMBs). However, achieving homogeneous ionic conductivity, excellent mechanical properties, and superior interfacial stability remains challenging due to interference from hard‐phase domains in ion transport and solid‐solid interface issues with lithium metal. Herein, we present a dynamic supramolecular ion‐conducting poly (urethane‐urea) interphase (DSIPI) that achieves these three properties through modulating the hard‐phase domains and constructing a composite SEI in situ. The soft‐phase polytetrahydrofuran backbone, featuring loose Li+−O coordinating interactions, ensures uniform Li+ transport. Concurrently, sextuple hydrogen bonds in the hard phase dissipate strain energy through sequential bond cleavage, thereby imparting exceptional mechanical properties. Moreover, enriched bis (trifluoromethanesulfonyl) imide anion (TFSI−) in DSIPI promotes the in situ formation of a stable polymer‐inorganic composite SEI during cycling. Consequently, the DSIPI‐protected lithium anode (DSIPI@Li) enables symmetric cells with exceptional cyclability exceeding 4,000 hours at an ultra‐high current density of 20 mA cm−2, thereby demonstrating excellent cycling stability. Furthermore, DSIPI@Li facilitates stable operation of the pouch cells under the constraints of a high‐loading LiNi0.8Co0.1Mn0.1O2 cathode and low negative/positive capacity (N/P) ratio. This work presents a powerful strategy for designing artificial SEIs and high‐performance LMBs.

Sulfurized Composite Interphase Enables a Highly Reversible Zn Anode.

The stability and reversibility of Zn anode can be greatly improved by in-situ construction of solid electrolyte interphase (SEI) on Zn surface via a low-cost design strategy of ZnSO4 electrolyte. However, the role of hydrogen bond acceptor -SO3 accompanying ZnS formation during SEI reconstruction is overlooked. In this work, we have explored and revealed the new role of -SO3 and ZnS in the in-situ formed sulfide composite SEI (SCSEI) on Zn anode electrochemistry in ZnSO4 aqueous electrolytes. Structure characterization and DFT demonstrate that the introduction of -SO3 can not only reduce the dehydration energy of [Zn(H2O)6]2+, but also enhance the stability of the ZnS/Zn interface and homogenize the ZnS/Zn interface electric field, thereby significantly improving the dynamic kinetics and uniform deposition of Zn2+. Owing to the synergistic effect of ZnS and -SO3, a high cycling stability of 1500 h with a cumulative-plated capacity of 7.5 Ah cm-2 at 10 mA cm-2 has been achieved within the symmetrical cell. Furthermore, the full cell with NH4V4O10 cathode exhibits outstanding cyclic stability, exceeding 2000 cycles at 5 A g-1 and maintaining a Coulombic efficiency of 100%. These new insights into anionic synergistic strategy could significantly enhance the practical application of zinc-ion batteries.

Sulfurized Composite Interphase Enables a Highly Reversible Zn Anode

The stability and reversibility of Zn anode can be greatly improved by in‐situ construction of solid electrolyte interphase (SEI) on Zn surface via a low‐cost design strategy of ZnSO4 electrolyte. However, the role of hydrogen bond acceptor ‐SO3 accompanying ZnS formation during SEI reconstruction is overlooked. In this work, we have explored and revealed the new role of ‐SO3 and ZnS in the in‐situ formed sulfide composite SEI (SCSEI) on Zn anode electrochemistry in ZnSO4 aqueous electrolytes. Structure characterization and DFT demonstrate that the introduction of ‐SO3 can not only reduce the dehydration energy of [Zn(H2O)6]2+, but also enhance the stability of the ZnS/Zn interface and homogenize the ZnS/Zn interface electric field, thereby significantly improving the dynamic kinetics and uniform deposition of Zn2+. Owing to the synergistic effect of ZnS and ‐SO3, a high cycling stability of 1500 h with a cumulative‐plated capacity of 7.5 Ah cm‐2 at 10 mA cm‐2 has been achieved within the symmetrical cell. Furthermore, the full cell with NH4V4O10 cathode exhibits outstanding cyclic stability, exceeding 2000 cycles at 5 A g‐1 and maintaining a Coulombic efficiency of 100%. These new insights into anionic synergistic strategy could significantly enhance the practical application of zinc‐ion batteries.

Ultra-Tough Dynamic Supramolecular Ion-Conducting Elastomer Induced Uniform Li+ Transport and Stabilizes Interphase Ensures Dendrite-Free Lithium Metal Anodes.

Artificial polymer solid electrolyte interphases (SEIs) with microphase-separated structures provide promising solutions to the inhomogeneity and cracking issues of natural SEIs in lithium metal batteries (LMBs). However, achieving homogeneous ionic conductivity, excellent mechanical properties, and superior interfacial stability remains challenging due to interference from hard-phase domains in ion transport and solid-solid interface issues with lithium metal. Herein, we present a dynamic supramolecular ion-conducting poly (urethane-urea) interphase (DSIPI) that achieves these three properties through modulating the hard-phase domains and constructing a composite SEI in situ. The soft-phase polytetrahydrofuran backbone, featuring loose Li+-O coordinating interactions, ensures uniform Li+ transport. Concurrently, sextuple hydrogen bonds in the hard phase dissipate strain energy through sequential bond cleavage, thereby imparting exceptional mechanical properties. Moreover, enriched bis (trifluoromethanesulfonyl) imide anion (TFSI-) in DSIPI promotes the in situ formation of a stable polymer-inorganic composite SEI during cycling. Consequently, the DSIPI-protected lithium anode (DSIPI@Li) enables symmetric cells with exceptional cyclability exceeding 4,000 hours at an ultra-high current density of 20 mA cm-2, thereby demonstrating excellent cycling stability. Furthermore, DSIPI@Li facilitates stable operation of the pouch cells under the constraints of a high-loading LiNi0.8Co0.1Mn0.1O2 cathode and low negative/positive capacity (N/P) ratio. This work presents a powerful strategy for designing artificial SEIs and high-performance LMBs.

A Novel Anion Receptor Additive for −40 °C Sodium Metal Batteries by Anion/Cation Solvation Engineering

AbstractSodium metal batteries, known for their high theoretical specific capacity, abundant reserves, and promising low‐temperature performance, have garnered significant attention. However, the large ionic radius of Na+ and sluggish transport kinetics across the interfacial structure hinder their practical application. Previous reviews have rarely regulated electrolyte performance from the perspective of anions, as important components of the electrolyte, the regulation mechanism is not well understood. Herein, a novel anion receptor additive, 4‐aminophenylboronic acid pinacol ester (ABAPE), is proposed to weaken the coupling between anions and cations and accelerate Na+ transport kinetics. The results of theoretical calculations and X‐ray photoelectron spectroscopy with deep Ar‐ion etching demonstrate that the introduction of this additive alters the solvation structure of Na+, reduces the desolvation barrier and forms a stable and dense electrode‐electrolyte interface. Moreover, ABAPE forms hydrogen bonds (−NH ⋅ ⋅ ⋅ O/F) with H2O/HF, effectively preventing the hydrolysis of NaPF6 and stabilizing acidic species. Consequently, the Na||Na symmetric cell exhibits excellent long‐cycle performance of 500 h at 1 mA cm−2 and 0.5 mAh cm−2. The Na||Na3V2(PO4)3 (NVP) cell with the addition of ABAPE maintains a capacity retention of 84.29 % at 1 C after 1200 cycles and presents no capacity decay over 150 cycles at −40 °C.

Dendrite‐Free Zinc Anode for Zinc‐Based Batteries by Pre‐Deposition of a Cu–Zn Alloy Layer on Copper Surface via an In Situ Electrochemical Oxidation–Reduction Reaction

ABSTRACTThe prevention of uncontrollable growth of zinc dendrites on the zinc electrodes is one of the key challenges, hindering the widespread commercialization of zinc‐based energy storage technologies. Herein, we report a facile method to mitigate dendrite growth on a copper surface by an initial in situ coating of a Cu–Zn alloy layer, before zinc deposition. During further zinc deposition, the initially formed Cu–Zn alloy layer provides uniform nucleating sites and promotes homogeneous zinc deposition. A symmetrical cell, assembled using a Cu–Zn/Cu electrode could be stably cycled for over 1000 cycles in ZnSO4 solution, at a current density of 30 mA/cm2 and a coulombic efficiency of 99.9%. A zinc–air cell, assembled using Zn@Cu–Zn/Cu as the anode and rGO/Co3O4 composite as the cathode, exhibited a very stable performance at a high current density of 50 mA/cm2 and coulombic efficiency of ~93%, for over 400 cycles. After cycling experiments, the X‐ray photoelectron spectroscopy and the X‐ray diffraction analysis confirmed the formation of the Cu–Zn alloy layer. Hence, the present method provides an easy route for fabricating a dendrite‐free zinc electrode, for a wide range of zinc anode‐based batteries.

Highly Reversible Sodium Metal Batteries Enabled by Extraordinary Alloying Reaction of Single‐Atom Antimony

AbstractThe unique coordination configuration of single‐atom materials (SAMs) allows precise reaction control at atomic‐level and a potential of unusual electrochemical reaction. Nevertheless, it is a big challenge to prepare main group element with high loading content. Here, multifield‐regulated synthesis (MRS) technology is utilized to rapidly produce single‐atom antimony (Sb) metal with a high loading of 15 wt.%. Ab initio molecular dynamics simulations reveal the significantly enhanced reaction kinetics of Sb and nitrogen‐doped graphene by multi‐physics field coupling. Compared with common metallic Sb nanoparticles, atomically dispersed Sb displays remarkably improved electrochemical reaction kinetics and stable structure due to the negligible variation of stresses and volume expansion during the pseudocapacitive alloying‐dealloying process. Such extraordinary alloying reaction in well‐dispersed Sb atoms enabling homogeneous ion flow can serve as active nucleation sites for regulating even Na metal nucleation and growth. As a result, copper foil coated with only ≈3 µm thickness of such material exhibits a high Coulombic efficiency of up to 99.99%, an ultra‐low overpotential of 3 mV, and a long lifetime exceeding 2500 h in symmetrical cells. Furthermore, an anode‐free MRS‐SbSA||Na3V2(PO4)3 battery is constructed, which demonstrates exceptionally high energy density (≈362 Wh Kg−1), outstanding rate capability and good cycling stability.

Replenish the Electron-Deficient State of Carbonyl Carbon Atoms to Achieve Stable Li-S Battery.

Carbonate-based electrolytes are widely used in Li-ion batteries (LIBs) due to their safe, stable properties and wide operating temperature range. However, the nucleophilic attack at carbonyl carbon atoms by polysulfide anions and the low solubility of lithium nitrate (LiNO3<0.1m) in carbonate-based electrolytes seriously hinder the application of lithium-sulfur (Li-S) batteries in carbonate-based electrolytes. Herein, the electrophilicity of carbonyl carbon atoms is gradually reduced through solvent molecules redesign, eliminated the attack of polysulfide anions on carbonyl carbon atoms, and also changed the intermolecular interactions in the electrolyte, improving the solubility of LiNO3 (>1.0m) and forming stable LiNxOy-containing SEI on the surface of the lithium metal. The assembled Li-S battery with these designed solvent molecules delivers an initial discharge capacity of 1251.7mAhg-1 at 0.1C. In addition, the lithium-sulfur battery assembled with the designed solvent molecule has a discharge capacity of 631mAhg-1 after 420 cycles at 0.2 C, with a capacity retention of ≈60%. Moreover, the Li||Li symmetrical cell shows stable cycle performance over 1200h at 0.5mAcm-2 and 0.5mAhcm-2.

Achieving Dendrite-Free Lithium Metal Batteries by Constructing a Dense Lithiophilic Cu1.8Se/CuO Heterojunction Tip.

Lithium (Li)metal batteries (LMBs) have garnered widespread attention due to their high specific capacity. However, the growth of lithium dendrite severely limits their practical applications. Herein, a novel strategy is proposed to regulate the overall potential strength and lithium ions (Li+) concentration on the surface of the current collector by utilizing densely distributed tip effects. This concept is exemplified through the construction of lithiophilic Cu1.8Se/CuO heterojunction needle array on the Cu foil, ultimately achieving dendrite-free lithium deposition. Based on the simulation in COMSOL multiphysics and experimental research, this design is demonstrated to enrich Li+ on the current collector surface, delay the formation of space charge regions, and mitigate the growth of lithium dendrites. Additionally, a built-in electric field (BIEF) triggered by the heterointerface between Cu1.8Se and CuO further alleviates the Li+ concentration gradient on the electrode surface, achieving uniform bottom-up deposition of Li within the array structure. Consequently, the symmetrical cell exhibits an ultra-long cycle life of 2400h (1mAcm-2, 1mAhcm-2) with an extremely low overpotential of 13mV. Furthermore, full batteries using LiFePO4 as the cathode exhibit superior cycle stability and rate performance. This study presents a promising approach for designing dendrite-free current collectors in LMBs.

Biomineralization Inspired the Construction of Dense Spherical Stacks for Dendrite-Free Zinc Anodes.

Aqueous zinc-ion batteries (AZIBs) are considered to be one of the most promising energy storage systems due to their high degree of safety and low cost. However, the deposition of the uncontrolled zinc dendritic morphology on the surface of the Zn anode seriously reduces the cycle life of AZIBs. Herein, inspired by natural biomineralization, a uniform spherical zinc deposition is achieved via the addition of a biological macromolecule to the electrolyte. The proposed biological macromolecule makes Zn2+ undergo dense spherical deposition by regulating the relative growth rate of high-index planes of metal zinc, effectively avoiding the destruction from irregular zinc dendrites. The symmetric cell with the addition of such a biological macromolecule can be stably cycled for >3200 h at 1 mA cm-2 for 1 mAh cm-2. This work sheds light on expanding morphological regulation of metal deposition to spherical shapes for stable metal anodes in addition to a single-crystal plane control strategy.

Difluorobenzene as an Antisolvent for Fluorinated Electrolyte to Achieve Unparalleled Cycle Life of Lithium Metal Battery.

Electrolytes play a crucial role in enhancing the cycling stability and overall lifespan of lithium metal batteries (LMBs). However, conventional electrolytes achieve ununiform and low ionic conductivity solid electrolyte interphase (SEI), leading to uncontrolled lithium dendrite growth and dead lithium formation, rendering them inadequate for meeting the performance of high energy density LMBs. Herein, a 1,2-difluorobenzene (1,2-dFBn) is introduced as antisolvent in fluorinated electrolyte which is composed of fluoroethylene carbonate (FEC) and lithium bis(trifluoromethanesulfonyl)imide (LiTFSI). The low energy level of the lowest unoccupied molecular orbital (LUMO) and the high fluorine-donating ability of 1,2-dFBn jointly modify the solvation structure and electrode/electrolyte interphase chemistry. As a result, this simple electrolyte formulation enables the Li||Li symmetric cells exhibit remarkable stability, enduring 700 h of continuous cycling under 2 mA cm-2 and Li||Cu cell achieve an impressive average Coulombic efficiency (CE) of 99.76%. Moreover, the full cell assembled with electrochemically deposited lithium capacity of 5 mAh cm-2 and LiFePO4 (LFP) as cathode achieves exceptional performance, maintaining a discharge specific capacity of 134.9 mAh g-1 while retaining 95.1% capacity at 2C after 1000 cycles. This study offers a plausible ratio design for fluorinated electrolyte, which achieving high CE and long-life LMBs.

Engineering in situ heterometallic layer for robust Zn electrochemistry in extreme Zn(BF4)2 electrolyte environment

The performance of zinc metal batteries is critically affected by the electrolyte environment originating from various zinc salt formulations. Zn(BF4)2, in particular, offers a notable cost advantage and its fluoride-containing groups facilitate the formation of a beneficial ZnF2 interfacial layer, thereby making it a promising candidate for application. Nonetheless, the strong acidity of the Zn(BF4)2-based electrolyte exacerbates the dendrite formation and promotes parasitic reactions, leading to rapid battery failure. Herein, M(BF4)n (M: Cu, Sn, In) salts were adopted as additives in Zn(BF4)2 electrolyte to in situ construct the heterometallic layers. Through comparison, the In(BF4)3-derived ZnIn interface demonstrates superior corrosion-resistance capability and the strongest zinc affinity, protecting the anode from acidic erosion and accelerating the Zn2+ transportation kinetics. The symmetric cell with the optimized electrolyte exhibits a long lifespan of 2500 cycles while the full cell involving the polyaniline cathode also presents a high capacity retention of 81.3 % after 1500 cycles, outperforming the cell with the original Zn(BF4)2 electrolyte. The strategy of generating an interface layer within the battery through electrolyte additives can be readily applied to other metal battery technologies.

Sn Penetrated Zincophilic Interface Design in Porous Zn Substrate for High Performance Zn-Ion Battery.

Rechargeable zinc-ion batteries are considered an ideal energy storage system due to their low cost and nonflammable aqueous electrolyte. However, dendrite growth, hydrogen evolution reaction, and self-corrosion of zinc anode brought about serious safety risks including short circuits and electrode expansion. Therefore, a modified host-design strategy with a 3D porous structure and bulk-phase penetrated zincophilic interface is proposed to boost the stability and lifetime of the Zn anode. The porous Zn substrate is constructed by universal HCl etching and the uniform and tight Sn-penetrated zincophilic interface is formed by effective electron beam evaporation (EBE). The porous substrate can uniform zinc ion flux and the Sn coating could effectively improve zinc ion deposition behavior, thus inhibiting the risk of dendrites growth and side reaction. As a result, the 3D Zn substrate with Sn interface (3D Zn@Sn) exhibits prolonged galvanostatic cycling performance up to 4500h with a low polarization of ≈25mV (1mAcm-2, 1mAhcm-2) in the symmetric cell. The full cell assembled with KVOH@Ti could maintain a high specific capacity of 148.6mAhg-1 after 500 galvanostatic cycles (10Ag-1). This work proposed an improved electrode design to realize the high performance of zinc ion batteries.