Artificial Interphase Research Articles

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

AbstractThe 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.

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.

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

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

Optimising structural health monitoring systems: A 2D numerical investigation on impedance matching for FML with integrated sensors

AbstractFibre metal laminates (FML) represent an innovative class of advanced composite materials that integrate the mechanical properties of both metals and fibre‐reinforced composites (FRP). Combining the strength and ductility of metals with the lightweight and high stiffness of FRP and FMLs have emerged as new material compositions for applications in chemical, nuclear, automobile, and aerospace engineering disciplines. Structural health monitoring (SHM) using guided ultrasonic waves (GUW) is the state‐of‐the‐art for non‐destructive testing of thin‐walled structures. When applied to FML, SHM plays a crucial role in monitoring the integrity over time and detecting potential damage such as delamination, fibre breakage, or other structural anomalies. In SHM with GUW, a wave‐field is emitted by actuators. This wave‐field can be affected by damage in the structure, thereby changing its propagation characteristics. Sensors monitor the interaction between damage and GUW, which can be utilized to locate and classify the damage and ascertain the overall health state of the structure. In this study, an advanced integration of measurement hardware, that is, sensors and actuators, within the laminate structure is investigated. Sensor integration into FML allows for improved and more sophisticated monitoring capabilities in comparison to measuring techniques like laser vibrometers, which are limited to measuring displacements on the surface of the structure. However, the integration of sensors and actuators yields the technical difficulty of distorting the wave‐fields and may result in an over‐ or underestimation of the damage. Similar to damage, the distortion of the wave‐field is caused by the changes in acoustic impedance resulting from different material properties. In a previous study, incorporating a functionally graded artificial interphase through acoustic impedance matching between the sensor and host material showed notable and significant outcomes. The current contribution extends the prior graded artificial interphase for an isotropic homogeneous material to an FML structure. This paper presents a comprehensive numerical simulation study on a two‐dimensional model of FML with integrated sensors. The interphases are designed based on impedance matching, which improves signal transmission and reduces disturbing reflections. The conducted investigations hold for several interphase configurations for a wide frequency range. The optimised integration of sensors demonstrates promising results for enhancing the reliability and accuracy of SHM systems. This research serves as a foundation for further experimental validation and the development of advanced sensor‐integrated FML structures with improved monitoring capabilities.

Modulating Interfacial Zn2+ Desolvation and Transport Kinetics through Coordination Interaction toward Stable Anodes in Aqueous Zn-Ion Batteries.

Aqueous Zn-ion batteries (AZIBs) are promising candidates for grid-scale energy-storage applications, but uneven Zn2+ flux distribution and undesirable water-related interfacial side reactions seriously hinder their practical application. Herein, a strategy of regulating the coordination interaction between Zn2+ and artificial interphase layers (AILs) to modulate the interfacial Zn2+ desolvation/transport behaviors and relieve side reactions for building stable Zn anodes is proposed. By selectively choosing appropriate polymers with different functional groups, it is shown that compared with the strong interaction offered by aryl groups in polystyrene-based AILs, cyano groups in polyacrylonitrile (PAN)-based AILs provide a moderate coordination interaction with Zn2+, which not only accelerates interfacial Zn2+desolvation kinetics but also enables efficient Zn2+ transport within AILs. Moreover, the Zn2+ transport kinetics of PAN-based AILs can be further enhanced with the incorporation of an ionic conductor, zinc phosphate (ZP). Because of these advantages, the Zn anodes decorated with the hybrid AILs composed of PAN and ZP can steadily operate for >2000h at 0.2mA cm-2 and >350h at a high current density of 10mA cm-2. This work provides a valuable guideline for selective design of AILs at the molecular level for durable AZIBs.

Review on Artificial Interphases for Lithium Metal Anodes: From a Mechanical Perspective

AbstractLithium (Li) metal is a promising candidate for next‐generation high‐energy‐density rechargeable batteries. However, the solid electrolyte interphase (SEI) inevitably suffers from mechanical fracture owing to the large morphological change during Li cycling, leading to the uncontrollable growth of Li dendrites, low Coulombic efficiency, and short cycle life. The fabrication of an artificial interphase is an effective strategy for improving the performances of Li metal anodes. The ideal artificial interphase should provide sufficient mechanical robustness to suppress dendritic Li growth and accommodate large volume changes during Li deposition‐dissolution cycles. In this review, we focus on the fabrication of mechanically robust artificial interphases for stabilizing Li‐metal anodes, including the underlying mechanism of SEI fracture, quantitative requirements for mechanical properties, measurements of mechanical properties, and recent progress in the fabrication of mechanically stable artificial interphases.

Construction of Fluoride‐Rich Interphase for Sustained Magnesiophilic Site Release Toward High‐Stability Chloride‐Free Magnesium Metal Batteries

AbstractRechargeable magnesium batteries (RMBs) have the potentials in terms of high energy density, resource abundancy and safety beyond current lithium‐ion batteries. However, the bare Mg metal electrode is prone to be passivated by solvents, suffering from the extremely high overpotential and short life during cycling. Herein, a facile chloride‐free solution pretreatment method for Mg anode is developed to construct the fluoride‐rich artificial interphase. Driven by the strong‐Lewis‐acidity trifluoromethanesulfonate anion, the interphase consisting of magnesiophilic and fluoride‐rich components are constructed by the substitution reaction of Mg metal with antimony trifluoride. The formed porous Sb‐based skeletons can uniform the electric‐field distribution and Mg ions flux at anode side, inducing the self‐adapting dendrite‐free Mg deposition even under large current density. The generated alloyable metal fluoride enables to lower the desolvation energy barrier for Mg ions and sustainedly release metallic antimony to compensate for the potentially invalid magnesiophilic sites during cycling. Therefore the symmetric cells with modified Mg anodes achieve the excellent cycling over 2000 h at 1 mA cm−2 and under a high areal capacity of 5 mAh cm−2. The full cells with CuS cathodes exhibit a superior high voltage stability (2.6 V vs Mg/Mg2+) and high coulombic efficiency close to 100%.

Multi‐Scale Functionally Designed ZnWO4 Artificial Interphase for Ultra‐Stable Aqueous Zn Metal Anodes Under High Current Rates

AbstractAqueous zinc ion batteries have received unprecedented attention owing to their superior safety and sustainability, yet their cycling stability especially at high current rates is greatly limited by the poor reversibility of Zn metal anodes, due to the delayed ion transport, severe water‐induced side reactions, and uncontrollable dendrites growth at electrolyte/electrode interface. Herein, a robust and multi‐scale functionally designed amorphous ZnWO4 (ZWO) artificial interphase that fully addresses the aforementioned issues, is proposed. The modified Zn anodes deliver remarkable stability, surpassing 3000 h of operation at a high current density of 20 mA cm−2 in symmetrical cells. Even under harsh conditions of 20 mA cm−2 and 10 mAh cm−2, the electrode demonstrates steady cycling for over 600 h with low overpotential. The excellent cycling stability and rate performance are mainly attributed to a range of collective functionalities of ZWO interphase, including short‐range and isotropic ion migration, superior ion‐screening capability, and a thermodynamically enhanced energy barrier for hydrogen evolution reaction (HER) during Zn plating. These findings highlight the significance of the multi‐scale functional interphase in overcoming key barriers associated with zinc anodes under high current density, offering a facile and insightful approach for achieving high‐performance Zn metal anodes.

Elucidating the role of polar functional groups in fluorinated polymer artificial interphase for stable lithium anodes

The properties of solid electrolyte interphase (SEI) are pivotal for stable lithium (Li) metal anodes. However, the process of formation and ion transport behavior of lithium fluoride (LiF) through the polar groups of organic fluorinated artificial SEI has not been clearly elucidated. Herein we demonstrate that the key role of polar functional groups in fluorinated polymer artificial SEI (FPASEI) is elucidated by using 2,2,2-trifluoroethylacrylate (TFEA) through radical polymerization. Density functional theory and ab initio molecular dynamics calculations demonstrate that the abundant CO polar groups in TFEA contribute a large number of electrons, thereby facilitating the degradation kinetics of CF bond cleavage in lithium bis(trifluoromethanesulfonyl)imide salt to yield LiF. Moreover, the presence of CF, COC, and CO groups in TFEA facilitate the migration of Li+ towards interchain regions through cation-dipole interaction, leading to dendrite-free Li deposition. The implementation of FPASEI in a Li||Li cell results in 500 h of Li plating/stripping cycling at 1 mA cm−2 and retains a capacity retention rate of 80 % after 265 cycles in Li||LiNi0.8Co0.1Mn0.1O2 cell. This study not only emphasizes the critical role of polar groups in artificial SEI but also presents a promising strategy for achieving stable Li metal batteries.

Ternary Mg alloy-based artificial interphase enables high-performance rechargeable magnesium batteries

Rechargeable magnesium batteries (RMBs) provide potential advantages over lithium-ion batteries in terms of high volumetric capacity, natural abundance, and high safety. However, the rational design of high-performance magnesium-based metal anodes compatible with conventional electrolytes is a big challenge for the viability of RMBs. In this work, an in-situ formed ternary alloy-based artificial interphase layer on Mg foil as an anode was successfully prepared through a facile and universal electrodeposition strategy. The Mg-Sn-Bi@Mg anode provides high charge transfer dynamics for Mg deposition and constructs a reduced energy barrier for Mg2+ ions desolvation. Thanks to the unique Mg deposition behaviors, the Mg-Sn-Bi@Mg alloy anode demonstrates a low overpotential of 39.4 mV and a long cycle life of >2000 h. The transfer kinetics for RMBs can be largely improved due to the unique alloying reactions. Density functional theory (DFT) calculations demonstrate that the designed ternary alloy-based artificial interphase layer enables faster Mg2+ ion migration than the bare Mg electrode. Full cells with Mo6S8 cathode also show ultra-stable cycling performance over 2400 cycles at 1C in a conventional all-phenyl complex (APC) electrolyte. This facile interface modification strategy sheds light on the development of advanced RMBs and also provides a promising direction for the design of high-performance Mg-based alloy anodes for high-performance RMBs and beyond.

Realizing the dendrite-free sulfide-based all-solid-state Li metal battery by surface design

Although the ultrahigh ionic conductivity of sulfide-type solid electrolytes is comparable to that of liquid electrolytes, the low critical current density (CCD) limits the practical application of solid-state lithium (Li) metal batteries. The insufficient Li0 self-diffusion in solid Li leads to the voids that form at the interface at a large stripping current density, which results in interface contact loss and the increase of local current density. Herein, an artificial hybrid interphase layer dominated by Li3Sb and LiF was constructed on the Li surface to explore the Li plating/stripping behavior at the Li/Li6PS5Cl interface. The Li3Sb alloy provides a fast Li0 diffusion channel to avoid the interfacial voids formation and current focusing, while the electrically insulated LiF acts an electron blocking shield at the Li/Li6PS5Cl interface. Consequently, the symmetric cells reveal a significantly increased CCD of 1.8 mA cm−2 and a stable Li plating/stripping for 1472 h with a high current density of 2 mA cm−2 at 50 °C. Moreover, the all-solid-state Li-SPAN cell with Li3Sb/LiF interphase exhibits good capacity retention of 83.2 % after 120 cycles at 0.5 C, and it also delivers a superior rate performance of 400 mAh g−1 at 5C. The construction of lithium-alloy interphase is a promising alternative to solid-state lithium battery applications.

3D Ternary Alloy Artificial Interphase Toward Ultra‐Stable and Dendrite‐Free Aqueous Zinc Batteries

AbstractRechargeable aqueous zinc‐ion batteries (AZIBs) are one of the most promising post‐lithium battery technologies due to their low cost, high safety, and environmental friendliness. However, their practical development is hindered by the issues of Zn metal anodes, including dendrite growth, passivation, hydrogen evolution and other side reactions. Herein, to circumvent these issues, a facile and universal alloy electrodeposition strategy is proposed to construct a 3D structured ternary Zn alloy artificial interphase layer on Zn foil as an anode for high‐performance AZIBs. The density functional theory (DFT) theoretical calculations, in situ optical visualization and spectroscopic results validate that the zincophilic Zn─Sn─Bi@Zn ternary alloy anode with lower migration energy barrier and weak hydrogen adsorption sites can promote the uniform Zn deposition and suppress hydrogen evolution reactions. The Zn─Sn─Bi@Zn//NH4V4O10 full cell demonstrates a high specific capacity 110.4 mAh g−1 even after 10 000 cycles at 5.0 A g−1. Notably, the full cell with a high NH4V4O10 cathode loading mass of ≈20.0 mg cm−2 maintains cyclic stability for 400 cycles. This work proposes an innovative Zn‐based ternary alloy anode methodology as a design strategy for advanced AZIBs and beyond.

In-situ polymerized electrolyte from a bifunctional additive for Li+ bulk phase migration and high-flux interface transport in lithium metal batteries

As a promising candidate of next-generation high-energy storage system, lithium metal batteries (LMBs) are still hindered by safety problems mainly derived from the leakage of liquid electrolytes and growth of lithium dendrite. Hence, electrolyte design and modification of electrode interphase become a feasible strategy for future exploitation of LMBs. Critically, bulk phase migration and high-flux interface transport of Li+ present inspiration. Herein, we introduce a bifunctional initiator, antimony trifluoride (SbF3), to in-situ form poly-DOL electrolyte (PDOL, 4 mg SbF3 10DOL-1DME) and build an anode interphase containing LiF and Li3Sb alloy hybrid, of which the system has high ion conductivity (1.404 mS cm−1), required Li+ migration path and intellectualized artificial interphase film. With the guidance of fast charge transport channel and in the effort of interface functionalization, Li+ obtains fast transition channels and high-flux interfacial flow, the batteries with SbF3 display superior cycling stability. It provides an accessible method to manufacture eligible quasi-solid LMBs for improved safety application.

Boosting the Interfacial Stability of the Li6PS5Cl Electrolyte with a Li Anode via In Situ Formation of a LiF-Rich SEI Layer and a Ductile Sulfide Composite Solid Electrolyte.

Due to its good mechanical properties and high ionic conductivity, the sulfide-type solid electrolyte (SE) can potentially realize all-solid-state batteries (ASSBs). Nevertheless, challenges, including limited electrochemical stability, insufficient solid-solid contact with the electrode, and reactivity with lithium, must be addressed. These challenges contribute to dendrite growth and electrolyte reduction. Herein, a straightforward and solvent-free method was devised to generate a robust artificial interphase between lithium metal and a SE. It is achieved through the incorporation of a composite electrolyte composed of Li6PS5Cl (LPSC), polyethylene glycol (PEG), and lithium bis(fluorosulfonyl)imide (LiFSI), resulting in the in situ creation of a LiF-rich interfacial layer. This interphase effectively mitigates electrolyte reduction and promotes lithium-ion diffusion. Interestingly, including PEG as an additive increases mechanical strength by enhancing adhesion between sulfide particles and improves the physical contact between the LPSC SE and the lithium anode by enhancing the ductility of the LPSC SE. Moreover, it acts as a protective barrier, preventing direct contact between the SE and the Li anode, thereby inhibiting electrolyte decomposition and reducing the electronic conductivity of the composite SE, thus mitigating the dendrite growth. The Li|Li symmetric cells demonstrated remarkable cycling stability, maintaining consistent performance for over 3000 h at a current density of 0.1 mA cm-2, and the critical current density of the composite solid electrolyte (CSE) reaches 4.75 mA cm-2. Moreover, the all-solid-state lithium metal battery (ASSLMB) cell with the CSEs exhibits remarkable cycling stability and rate performance. This study highlights the synergistic combination of the in-situ-generated artificial SE interphase layer and CSEs, enabling high-performance ASSLMBs.

Rational design of F, N-rich artificial interphase via chemical prelithiation initiation strategy enabling high coulombic efficiency and stable micro-sized SiO anodes

Silicon monoxide (SiO) is regarded as a potential candidate for anode materials of lithium-ion batteries (LIBs). Unfortunately, the application of SiO is limited by poor initial Coulombic efficiency (ICE) and unsteady solid electrolyte interface (SEI), which induce low energy, short cycling life, and poor rate properties. To address these drawbacks of SiO, we achieve in-situ construction of robust and fast-ion conducting F, N-rich SEI layer on prelithiated micro-sized SiO (P-μSiO) via the simple and continuous treatment of μSiO in mild lithium 4, 4′-dimethylbiphenyl solution and nonflammable hexafluorocyclotriphosphazene solution. Chemical prelithiation eliminates irreversible capacity through pre-forming inactive lithium silicates. Meanwhile, the symbiotic F, N-rich SEI with good mechanical stability and fast Li+ permeability is conductive to relieve volume expansion of μSiO and boost the Li+ diffusion kinetics. Consequently, the P-μSiO realizes an impressive electrochemical performance with an elevated ICE of 99.57% and a capacity retention of 90.67% after 350 cycles. Additionally, the full cell with P-μSiO anode and commercial LiFePO4 cathode displays an ICE of 92.03% and a high reversible capacity of 144.97 mA h g−1. This work offers a general construction strategy of robust and ionically conductive SEI for advanced LIBs.

Inhibition of Vanadium Cathodes Dissolution in Aqueous Zn-Ion Batteries.

Aqueous zinc-ion batteries (AZIBs) have experienced a rapid surge in popularity, as evident from the extensive research with over 30 000 articles published in the past 5 years. Previous studies on AZIBs have showcased impressive long-cycle stability at high current densities, achieving thousands or tens of thousands of cycles. However, the practical stability of AZIBs at low current densities (<1C) is restricted to merely 50-100 cycles due to intensified cathode dissolution. This genuine limitation poses a considerable challenge to their transition from the laboratory to the industry. In this study, leveraging density functional theory (DFT) calculations, an artificial interphase that achieves both hydrophobicity and restriction of the outward penetration of dissolved vanadium cations, thereby shifting the reaction equilibrium and suppressing the vanadium dissolution following Le Chatelier's principle, is described. The approach has resulted in one of the best cycling stabilities to date, with no noticeable capacity fading after more than 200 cycles (≈720h) at 200mA g-1 (0.47C). These findings represent a significant advance in the design of ultrastable cathodes for aqueous batteries and accelerate the industrialization of aqueous zinc-ion batteries.

An artificial cathode-electrolyte interphase with flame retardant capability enabled by an organophosphorus compound for lithium metal batteries

An artificial cathode-electrolyte interphase (A-CEI) that can enhance the interfacial stability between the electrode and the electrolyte with fire suppression capability enabled by an organophosphorus compound.

An artificial cathode-electrolyte interphase enabling one-step sulfur transition in polyethylene oxide-based solid-state lithium–sulfur batteries

An artificial CEI is developed for PEO-based solid-state Li–S batteries, which inhibits the cohesion and dissolution of polysulfides in PEO and enables a one-step solid-state transition of sulfur.

Three-dimensional covalent organic framework-based artificial interphase layer endows lithium metal anodes with high stability.

To gain a deeper understanding and address the scientific challenges of lithium dendrite growth, a robust solid-state electrolyte interface (SEI) with good mechanical properties and rapid ion conduction is crucial for the advancement of lithium metal batteries. Artificial SEI layers based on organic polymers, such as covalent organic frameworks (COF), have garnered widespread attention due to their flexible structural design and tunable functionality. In this work, a COF with 3D spatial geometric symmetry and a fully covalent dia topology was synthesized and used as artificial SEI layers. A combination of comprehensive DFT calculations and ex situ/in situ characterizations have unraveled the impact of interpenetrated chain segments and anchoring lithiophilic groups on the microscopic dynamics related to Li ion desolvation, charge transfer, migration pathways, and deposition morphology. The ultralow polarization voltage of 46 mV for 9400 hours with a symmetric Li|Li cell at a harsh current density of 10 mA cm-2, as well as the high Li+ utilization, low polarization voltage, and prolonged lifespan for 3D-COF-modified Li|S and Li|LFP full cells, unambiguously corroborate the interphase reliability. This work also aims to shed new light on the use of multi-dimensional porous polymer SEI layers to revive highly stable Li metal batteries.

Integration of confinement crosslinking and in situ grafting for constructing artificial interphases toward stabilized zinc anodes

A novel strategy integrating confinement crosslinking and in situ grafting was developed to construct artificial solid electrolyte interface with effectively promoted heterogeneous compatibility and interfacial stability, achieving durable Zn anodes.