Stable Anode Research Articles

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.

Electrolysis-enhanced coagulation process for highly emulsified oily wastewater treatment: Floc diameter, oil removal performance and mechanism

Electrocoagulation (EC) is one of the most effective processes for highly emulsified oily wastewater (HEOW) treatment. However, the demulsification efficiency depends on the amount of aluminum or iron ions released from the conventional sacrificial metal anode, leading to challenges such as rapid anode dissolution and short lifespan. To address these issues, this study presents a novel electrolysis-enhanced coagulation (EEC) process, replacing conventional Al electrodes with dimensionally stable titanium anodes coated with ruthenium-iridium oxide and supplementing the electrochemically released Al³+ with externally added AlCl3.This process was assessed using the Turbiscan LAB Expert to measure the variation in floc diameter under various electrolysis times, AlCl3 concentrations, and current densities. At a current density of 5 mA/cm2 and AlCl3 dosage of 50 mg/L, the mean floc diameter increased from 32.4 ± 1.7 µm to 630.3 ± 76.9 µm as the electrolysis time extended from 0 to 4 min. Under optimal conditions, the oil removal efficiency of 96.7%±0.2% and residual oil concentration in the effluent of 66.3 ± 3.5 mg/L were achieved. The energy consumption of this process was 0.17 kWh/m³, which was a relatively low value compared with conventional EC techniques. Moreover, as electrolysis time increased, a greater proportion of dissolved and suspended Al transformed into species incorporated within the floating oil. These findings demonstrate the potential of the EEC process to replace EC in treating HEOW, providing an effective and durable solution.

3D-stacked electrospun iron-doped nickel cobalt oxide nanofibers as integrated electrodes for anion exchange membrane water electrolysis

The commercialization of anion-exchange membrane water electrolysis (AEMWE) requires the development of highly active, stable, and cheap anode catalysts for the oxygen evolution reaction (OER). In this study, we proposed electrospun iron-doped NiCo2O4 (NCO) nanofibers on nickel foam (NF) and evaluated the performances of the resulting samples (FeX-NCO/NF; X = iron loading in NCO (0, 5, 10, and 15 at %)) as unitized anodes for the OER. Among the fabricated electrodes, Fe10-NCO/NF exhibited the lowest overpotential of 352 mV at a current density of 50 mA cm−2 in a half-cell test owing to its improved intrinsic activity. In an AEMWE single-cell test, Fe10-NCO/NF as anode showed high current density (932 mA cm-2 at 1.8 V) and long-term stability for 150 h The improved AEMWE performance of Fe10-NCO/NF was attributed to efficient mass transport enabled by superhydrophilic three-dimensional porous structure featuring stacked nanofibers.

Lithium anode stability enhanced by micro-potentials from spontaneous polarization in BaTiO3 films

Lithium metal is widely recognized as an ideal anode material due to its high specific capacity and low redox potential. However, challenges such as severe lithium dendrite growth have significantly impeded its practical applications. Herein, we introduce a BaTiO3 (BTO) ferroelectric thin film into the lithium anode. During the charge/discharge cycles, the BTO film generates a micro-potential in the direction opposite to the applied electric field, owing to its spontaneous polarization. The micro-potential effectively reduces the electric field gradient, thereby suppressing inhomogeneous nucleation and the growth of lithium dendrites. Consequently, the incorporation of the BTO ferroelectric thin film significantly enhances the cycling performance of the batteries. The half cells demonstrate stable operation after more than 100 cycles at high capacity of 4 mAh cm−2. Furthermore, the LiFePO4 (LFP) full cell delivers a specific capacity of 146.6 mAh g−1 after 300 cycles. This work demonstrates a promising strategy for the development of lithium batteries with improved longevity and enhanced capacity.

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.

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.

Porous V2CTx MXene as a High Stability Zinc Anode Protective Coating.

Aqueous Zn batteries exhibit significant research potential owing to their environmental friendliness and high energy density. Nevertheless, the formation of dendrites on the zinc anode and the sluggish diffusion kinetics of zinc ions adversely affect the cycle life of zinc ion batteries. In this study, we employ porous V2CTx (MVMX) as a protective layer for the zinc anode. The uniform porous structure of MVMX promotes active site exposure and facilitates the transport of zinc ions. Remarkably, the Zn@Ti half-cell demonstrated an average CE of 99.7% in 1500 cycles. Furthermore, the Zn-Zn symmetric battery exhibited stable cycling for 1600 h at current densities of 5 mA cm-2 and 1 mAh cm-2. Additionally, the MVMX@Zn||V2O5 full cell exhibited a capacity of 198 mAh g-1 and retained a capacity of 124.75 mAh g-1 after 5000 cycles at 1 A g-1, demonstrating the potential of employing alternative MXenes for fabricating stable zinc anodes.

Molecular Chain Rearrangement of Natural Cellulose-Based Artificial Interphase for Ultra-Stable Zn Metal Anodes.

The unstable electrolyte-anode interface, plagued by parasitic side reactions and uncontrollable dendrite growth, severely hampers the practical implementation of aqueous zinc-ion batteries. To address these challenges, we developed a regenerated cellulose-based artificial interphase with synergistically optimized structure and surface chemistry on the Zn anode (RC@Zn), using a facile molecular chain rearrangement strategy. This RC interphase features a drastically increased amorphous region and more exposed active hydroxyl groups, facilitating rapid Zn2+ diffusion and homogeneous Zn2+ interface distribution, thereby enabling dendrite-free Zn deposition. Additionally, the compact texture and abundant negatively charged surface of the RC interphase effectively shield water molecules and harmful anions, completely preventing H2 evolution and Zn corrosion. The superior mechanical strength and adhesion of the RC interphase also accommodate the substantial volume changes of Zn anodes even under deep cycling conditions. Consequently, the RC@Zn electrode demonstrates an outstanding cycling lifespan of over 8000 hours at a high current density of 10 mA cm-2. Significantly, the electrode maintains stable cycling even at a 90 % depth of discharge and ensures stable operation of full cells with a low negative/positive capacity ratio of 1.6. This study provides new solution to construct highly stable and deep cycling Zn metal anodes through interface engineering.

Reaction Mechanism of Oxytetracycline Degradation by Electrogenerated Reactive Chlorine: The Influence of Current Density and pH.

A binary dimensionally stable anode Ti/TiO2-RuO2 electrode was used to abate the antibiotic oxytetracycline (OTC) (C22H24N2O9) in chloride water. The anode was prepared using the Pechini method and subsequently characterized by X-ray diffraction, scanning electron microscopy-energy-dispersive X-ray spectroscopy (SEM-EDS), and cyclic voltammetry (CV). The optimum values of the operational parameters affecting removal efficiency were determined using a 2 × 3 factorial design by screening j (6.0, 10, and 20 A m-2) and pH (3, 6.5, and 10). The textural analysis revealed the formation of active oxides (RuO2 and TiO2 coating rutile-type P42/mnm, space group 136), with a cracked surface and good dispersion of metal components. A contour graph verified that the most suitable condition for contaminant degradation was 20 A m-2 at a circumneutral pH of 6.5, resulting in approximately 97% degradation after 20 min of electrolysis according to pseudo-first-order reaction kinetics and the loss of the antibiotic activity of OTC. In addition, the results of oxidant formation and CV indicate that the best electrochemical activation of the anode to form Cl2-active mainly depended on pH. Liquid chromatography-mass spectrometry (LC-MS) and density functional theory were employed to propose a reaction pathway for OTC degradation. Three byproducts with m/z 426, 256, and 226 were identified corresponding to the removal of amide and amine groups, which are susceptible sites to electrophilic attack by active chlorine species. The findings from this work stand out for prospective applications of anodic electrochemical oxidation to efficiently eliminate antibiotics with similar chemical structures in wastewater containing chlorides.

Separator functionalization realizing stable zinc anode through microporous metal-organic framework with special functional group

Aqueous zinc ion batteries (AZIBs) have been regarded as one of the most promising energy storage systems because of their security, high specific capacity and abundant zinc resources, etc. Despite the promising prospects of AZIBs, their practical application is still plagued by dendrite and side reactions on zinc surface. In this paper, glass fiber separators were modified by in-situ loading metal-organic framework MIL-125 (M-125) and its -NH2-functionalized material (NM-125). The designed separator pore structure was successfully adjusted and endowed with -NH2 functional groups, which can ultimately dramatically enhance the electrochemical performance of AZIBs under practical operation conditions. The functionalized NM-125 with smaller pore size and particle size enables NM-125-GF to prevent the transport of macromolecular anions in the electrolyte, guiding and promoting zinc ions to undergo an orderly migration. In addition, -NH2 of NM-125 can adsorb Zn2+ and detach them from the solvated structure, inhibiting the generation of anode-side reactions and optimizing battery performance. Notably, Zn||MnO2 full cell assembled with -NH2 functionalized separator also shows a high initial discharge specific capacity (160.2 mAh g-1) with a high capacity retention of ∼99.8% even after 700 cycles. The rational design of the functionalized separator provides a useful guideline for optimizing high-performance AZIBs.

Triple-Layered Noncombustible PEO-Based Solid Electrolyte for Highly Safe Lithium-Metal Batteries.

Lithium-metal batteries are currently recognized as promising next-generation technologies owing to their high energy density. Solid polymer electrolytes, particularly those based on polyethylene oxide (PEO), are lauded for their leakage resistance, safety, and flexible design. Despite the ongoing fire safety- and ionic conductivity-related concerns, a novel noncombustible solid polymer electrolytes with superior ionic conductivities are introduced here with additive decabromodiphenyl ethane and zeolite. To enhance the mechanical strength and ensure soft interactions at the electrode interface, a triple-layer structure with self-extinguishing properties and robust ionic conductivity is proposed. Notably, the softness at the electrode interface intensifies as the LiTFSI concentration increases; this higher concentration negatively impacts PEO crystallinity, enhancing the ionic conductivity owing to the presence of free Li+ and TFSI- ions. This novel electrolyte can achieve a conductivity of 1.5 mS cm-1 at 60°C, maintain anodic stability up to 4.8V, and exhibit flame retardancy. Furthermore, adding LiTFSI at 60% relative to PEO is shown to reduce LiF formation on the surface, enhancing anode stability. The [LiFePO4/triple-layered electrolyte/Li] lithium-metal batteries are capable of an initial capacity of 153 mAh g-1, sustained superior capacity retention of 87.9%, and high Coulombic efficiency (99.6%) over 1000 cycles at a 1C rate.

Achieving stable lithium metal anode via constructing lithiophilicity gradient and regulating Li3N-rich SEI

Three-dimensional (3D) current collectors are studied for the application of Li metal anodes in high-energy battery systems. However, they still suffer from the preferential accumulation of Li on the outermost surface, resulting from an inadequate regulation of the Li+ transport. Herein, we propose a deposition regulation strategy involving the creation of a 3D lithiophilicity gradient structure of MoN on Cu3N nanowire-grown Cu foam (MCNCF) to induce a “bottom-up” Li deposition. During the initial Li deposition, the reaction between Li and Cu3N leads to the formation of Li3N while the lithiophilic MoN located at the bottom promotes the downward Li+ migration, resulting in the generation of a Li3N gradient. Such a “bottom-up” Li3N distribution results in the formation of a stable and Li3N-rich solid electrolyte interphase layer, facilitating the Li⁺ transport and promoting a uniform Li nucleation. Computational simulations and experimental results corroborate the preferential deposition of Li on the bottom of the substrate, leading to a uniform Li nucleation and growth throughout the electrode. The MCNCF electrode offers a significantly improved reversibility of the Li deposition, achieving a lifespan of more than 1200 h at a current density of 1 mA cm−2 in symmetric Li||Li cells. Furthermore, full-cells incorporating MCNCF@Li as the negative electrode and LiFePO4 cathodes exhibit outstanding electrochemical performance with a capacity retention of over 99.5 % after 250 cycles at 1 C, which significantly surpasses the performance achieved with CF@Li or CCF@Li electrodes. This innovative design strategy for 3D metallic current collectors, featuring a lithiophilicity gradient, provides new perspectives for the development of stable Li metal anodes and, as a result, for the advancement of Li-metal batteries.

Rational design of alginate-derived network binder for high-performance silicon-based anodes in Li-ion batteries

This study developed a novel alginate-derived network binder, SAH, to enhance the performance and stability of silicon-based anodes in lithium-ion batteries. Integrating acrylic acid and 2-hydroxyethyl acrylate with sodium alginate through a one-pot polymerization and in-situ cross-linking method, SAH effectively addresses the volumetric expansion challenges associated with silicon anodes. This innovative binder maintains the structural integrity of the silicon anode through its rigid acrylic acid component, while the flexible acrylic-2-hydroxyethyl ester serves as a dynamic buffer to enhance flexibility. Sodium alginate contributes its intrinsic beneficial properties and imparts a robust three-dimensional network structure through effective coupling, allowing the binder to accommodate silicon volume changes during battery operation. Consequently, lithium-ion batteries incorporating this binder exhibited improved stability and extended cycle life, achieving an impressive capacity retention rate of 87.3 % after 100 cycles at 0.5C. This study highlights the potential of biopolymeric materials in enhancing the functionality of silicon-based anodes, contributing to the ongoing development of high-performance energy storage technologies.

Modulating interfacial Zn2+ deposition mode towards stable Zn anode via bimetallic co-doped coating

Artificial coatings represent the promising means to address the interfacial issues of Zn anode, but it poses a significant challenge to their stability due to the fatigue and resulting cracking of coatings during repeated cycling. Here, a functional coating with the synergistic effect of bimetallic co-doping was developed, which changes the Zn2+ deposition mode to interlayer deposition in coating. The simultaneous doping of Cu2+ and In3+ reduces the pyrrolic N content and enhances the adsorption of Zn2+ in the active sites. Bimetallic co-doping results in an increase in specific surface area and a decrease in pore size, thus providing more active sites. As well as enhanced electrical conductivity, electrons can enter between the coatings, thus promoting redox reactions between the layers. Therefore, it endows surface coating with low polarization and stress buffering simultaneously, which avoids cracking and stripping of coatings during cycling. As a result, the cycle life of CuInZIF-8@Zn||CuInZIF-8@Zn symmetric cell exhibits more than 1200 h at 5 mA cm−2 and 5 mAh cm−2. The CuInZIF-8@Zn anode can match multiple types of cathodes and achieve excellent cycling stability; For instance, it can cycle stably for 3000 cycles when paired with vanadium-based cathode. This work provides a new perspective of artificial coatings towards highly stable Zn anode.

Breath inspired multifunctional low-cost inorganic colloidal electrolyte for stable zinc metal anode

The practical application of aqueous zinc-ion batteries (AZIBs) is primarily constrained by issues such as corrosion, zinc dendrite formation, and the hydrogen evolution reaction occurring at the zinc metal anode. To overcome these challenges, strategies for optimizing the electrolyte are crucial for enhancing the stability of the zinc anode. Inspired by the role of hemoglobin in blood cells, which facilitates oxygen transport during human respiration, an innovative inorganic colloidal electrolyte has been developed: calcium silicate-ZnSO4 (denoted as CS-ZSO). This electrolyte operates in weak acidic environment and releases calcium ions, which participate in homotopic substitution with zinc ions, while the solvation environment of hydrated zinc ions in the electrolyte is regulated. The reduced energy barrier for the transfer of zinc ions and the energy barrier for the desolvation of hydrated ions imply faster ion transfer kinetics and accelerated desolvation processes, thus favoring the mass transfer process. Furthermore, the silicate colloidal particles act as lubricants, improving the transfer of zinc ions. Together, these factors contribute to the more uniform concentration of zinc ions at the electrode/electrolyte interface, effectively inhibiting zinc dendrite formation and reducing by-product accumulation. The Zn//CS-ZSO//Zn symmetric cell demonstrates stable operation for over 5000 h at 1 mA cm−2, representing 29-fold improvement compared to the Zn//ZSO//Zn symmetric cell, which lasts only 170 h. Additionally, the Zn//CS-ZSO//Cu asymmetric cell shows stable average Coulombic efficiency (CE) exceeding 99.6% over 2400 cycles, significantly surpassing the performance of the ZSO electrolyte. This modification strategy for electrolytes not only addresses key limitations associated with zinc anodes but also provides valuable insights into stabilizing anodes for the advancement of high-performance aqueous zinc-ion energy storage systems.

Reduced Na–S bond adsorption of WSSe enabling fast reaction kinetics in the sodium-ion battery

WS2, a two-dimensional layered material, is promising as sodium-ion batteries (SIBs) anode due to its large interlamellar spacing and high sodium storage capacity. However, its low electronic conductivity and high Na+ adsorption energy hinder reaction kinetics. Here we demonstrate that substituting Se for part of the S in WS2 reduces interlayer Na+ adsorption and increases electronic conductivity. Based on this finding, lamellar WSSe, grown in situ on peanut shell-derived carbon (PSDC/WSSe), is elaborately designed as a highly stable SIB anode with a fast kinetic. PSDC/WSSe with carbon matrix and Se substitution simultaneously provides fast electron transport channels and lowered Na+ transport barriers (0.22 eV). The PSDC/WSSe anode offers a considerable reversible sodium storage capacity (288.0 mAh g−1 after 1000 cycles at 1.0 A g−1) and a fast kinetic reaction. A SIB full-cell using a PSDC/WSSe anode and Na3V2(PO4)3 cathode achieves a 215.4 Wh kg−1 high energy density, and successfully powers LEDs. This work offers new strategies to lower sodium ion transportation barrier in two-dimensional layered materials.

Minimizing solvated water via synergistic effect of salt anion and cosolvent enables stable Zn metal anodes in low-cost acetate electrolyte

Minimizing solvated water via synergistic effect of salt anion and cosolvent enables stable Zn metal anodes in low-cost acetate electrolyte

Porous amorphous high entropy oxide coated dimensionally stable anode for oxygen evolution reaction in acidic media

Porous amorphous high entropy oxide coated dimensionally stable anode for oxygen evolution reaction in acidic media

Toward waterproof magnesium metal anodes by uncovering water-induced passivation and drawing water-tolerant interphases.

Magnesium (Mg) metal is a promising anode candidate for high-energy and cost-effective multivalent metal batteries, but suffers from severe surface passivation in conventional electrolytes, especially aqueous solutions. Here, we uncover that MgH2, in addition to the well-known MgO and Mg(OH)2, can be formed during the passivation of Mg by water. The formation mechanism and spatial distribution of MgH2, and its detrimental effect on interfacial dynamics and stability of Mg anode are revealed by comprehensive experimental and theoretical investigations. Furthermore, a graphite-based hydrophobic and Mg2+-permeable water-tolerant interphase is drawn using a pencil on the surface of Mg anodes, allowing them to cycle stably in symmetric (> 900 h) and full cells (> 500 cycles) even after contact with water. The mechanistic understanding of MgH2-involved Mg passivation and the design of pencil-drawn waterproof Mg anodes may inspire the further development of Mg metal batteries with high water resistance.

Li+ Ion-Dipole Interaction-Enabled a Dynamic Supramolecular Elastomer Interface Layer for Dendrite-Free Lithium Metal Anodes.

The unstable lithium (Li)/electrolyte interface, causing inferior cycling efficiency and unrestrained dendrite growth, has severely hampered the practical deployment of Li metal batteries (LMBs), particularly in carbonate electrolytes. Herein, we present a robust approach capitalizing on a dynamic supramolecular elastomer (DSE) interface layer, which is capable of being reduced with Li metal to spontaneously form strong Li+ ion-dipole interaction, thereby enhancing interfacial stability in carbonate electrolytes. The soft phase in the DSE structure enables fast Li+ transport via loosely coordinated Li+-O interaction, while the hard phase, rich in electronegative lithiophilic sites, drives the generation of fast-ion-conducting solid electrolyte interface components, including Li3N and Li2S. Furthermore, the dynamically resilient DSE network composed of soft and hard phases protects Li anodes from electrolyte corrosion and accommodates volume changes during cycling. All features of the DSE layer synergistically facilitate uniform Li+ deposition and suppress Li dendrite propagation, ensuring a stable and dendrite-free Li anode. Consequently, the symmetric Li||Li cell incorporating the DSE layer achieves cycling stability exceeding 6000 h under 1 mA cm-2 and 1 mA h cm-2 conditions. Furthermore, full cell pairing DSE/Li anode with LiFePO4 (LFP) or high-voltage LiNi0.8Mn0.1Co0.1O2 (NMC811) cathodes exhibits high-efficiency Li deposition and cycling stability, even under constrained conditions of limited Li (40 μm) and ultrahigh loading NMC811 cathode (21.5 mg cm-2). This study underscores the effectiveness of the ion-dipole interaction-enabled DSE network in developing stable, high-energy-density LMBs.