Suppression Of Side Reactions Research Articles

CO2-Assisted Oxidative Dehydrogenation of Propane to Propylene over Modified SiO2 Based Catalysts

The oxidative dehydrogenation of propane with CO2 (CO2-ODP) was investigated over different metal oxides MxOy (M: Ca, Sn, Cr, Ga) supported on a SiO2 surface. Catalysts were characterized employing nitrogen adsorption/desorption, X-ray diffraction (XRD), CO2 temperature programmed desorption (CO2-TPD) and pyridine adsorption/desorption experiments in order to identify their physicochemical properties and correlate them with their activity and selectivity for the CO2-ODP reaction. The effect of operating reaction conditions on catalytic performance was also examined, aiming to improve the propylene yield and suppress side reactions. Surface acidity and basicity were found to be affected by the nature of MxOy, which in turn affected the conversion of propane to propylene, which was in all cases higher compared to that of bare SiO2. Propane conversion, reaction rate and selectivities towards propylene and carbon monoxide were maximized for the Ga- and Cr-containing catalysts characterized by moderate surface basicity, which were also able to limit the undesired reactions leading to ethylene and methane byproducts. High surface acidity was found to be beneficial for the CO2-ODP reaction, which, however, should not be excessive to ensure high catalytic activity. The silica-supported Ga2O3 catalyst exhibited sufficient stability with time and better than that of the most active Cr2O3-SiO2 catalyst. Decreasing the weight gas hourly space velocity resulted in a significant improvement in both propane conversion and propylene yield as well as a suppression of undesired product formation. Increasing CO2 concentration in the feed did not practically affect propane conversion, while led to a decrease in propylene yield. The ratio of propylene to ethylene selectivity was optimized for CO2:C3H8 = 5:1 and space velocity of 6000 mL g−1 h−1, most possibly due to facilitation of the C–H bond cleavage against that of the C–C bond. Results of the present study provided evidence that the efficient conversion of propane to propylene is feasible over silica-based composite metal oxides, provided that catalyst characteristics have been optimized and reaction conditions have been properly selected.

Biopolymer‐Based Gel Electrolytes for Advanced Zinc Ion Batteries: Progress and Perspectives

AbstractIn recent years, aqueous zinc ion batteries (ZIBs) with ultra‐high safety and environmental friendliness have emerged as a promising candidates for energy storage and energy conversion devices. However, the severe side reactions and dendrites issues discourage the practical application of ZIBs. Recently, biopolymer‐based gel electrolytes have disclosed large potential in tackling these challenges of ZIBs, with numerous advancements reported. Their advantages lie in suppressing side reactions including hydrogen evolution and Zn metal anode corrosion, as well as inhibiting the growth of Zn dendrites. This review comprehensively examines the classification, structures and properties of biopolymer‐based gel electrolytes, with a focus on hydrogel electrolytes derived from various natural macromolecular biopolymers, along with a brief discussion on non‐hydrogel electrolytes using ionic liquids or organic solutions as solvents. Subsequently, the preparation of biopolymer‐based gel electrolytes with physical and chemical methods are summarized. Furthermore, the practical applications of biopolymer‐based gel electrolytes in ZIBs with diverse cathodes materials are introduced. Finally, it highlights the environmental benefits and excellent electrochemical performance of biopolymer‐based gel electrolytes, outlining their prospects for the next generation of ZIBs and proposing future perspectives.

Multidentate Chelating Ligands Enable High-Performance Zinc-Bromine Flow Batteries.

Zinc bromine flow battery (ZBFB) is a promising battery technology for stationary energy storage. However, challenges specific to zinc anodes must be resolved, including zinc dendritic growth, hydrogen evolution reaction, and the occurrence of "dead zinc". Traditional additives suppress side reactions and zinc dendrite formation by altering the solvation structure of Zn2+ and adsorbing onto the zinc surface through only a limited number of zincophilic sites, resulting in weak adsorption on zinc metal and potential inability to simultaneously optimize the solvation structure of zinc ions. Obviously, increasing the number of potential zincophilic sites in the additive can significantly enhance the interaction with zinc. Herein, we propose a strong chelate, ethylenediamine tetramethylene phosphonic acid (EDTMPA) as the additive, which boasts six potent zincophilic sites, not only promotes the formation of the water-deficient inner Helmholtz plane but also plays a crucial role in restructuring the solvation environment of Zn2+. As a result, the zinc symmetric flow battery with EDTMPA exhibited exceptional coulombic efficiency of 99.4% over 800 cycles, surpassing the previous studies by a significant margin. Furthermore, the assembled ZBFB has showcased a dendrite-free and enduring cycling over 400 cycles at 80 mA cm-2.

Gradient Distribution of Zincophilic Sites for Stable Aqueous Zinc-Based Flow Batteries with High Capacity.

Current collectors, as reaction sites, play a crucial role ininfluencing various electrochemical performances in emerging cost-effective zinc-based flow batteries (Zn-based FBs). 3D carbon felts (CF) are commonly used but lack effectiveness in improving Zn metal plating/stripping. Here, a current collector with gravity-induced gradient copper nanoparticles (CF-G-Cu NPs) is developed, integrating gradient conductivity and zincophilicity to regulate Zn deposition and suppress side reactions. The CF-G-Cu NPs electrode modulates Zn nucleation and growth via the zincophilic Cu/CuZn5 alloy has been confirmed by density functional theory (DFT) calculations. Finite element simulation demonstrates the gradient internal structure effectively optimizes the local electric/current field distribution to regulate the Zn2+ flux, improving bottom-up plating behavior for Zn metal and mitigating top-surface dendrite growth. As a result, Zn-based asymmetrical FBs with CF-G-Cu NPs electrodes achieve an areal capacity of 30 mAhcm-2 over 640h with Coulombic efficiency of 99.5% at 40mAcm-2. The integrated Zn-Iodide FBs exhibit a competitive long-term lifespan of 2910h (5800 cycles) with low energy efficiency decay of 0.062% per cycle and high cumulative capacity of 112800 mAhcm-2 at a high current density of 100mAcm-2. This gradient distribution strategy offers a simple mode for developing Zn-based FB systems.

Constructing Dual Schottky Junctions for High‐Performance Zinc Anode

AbstractAqueous zinc ion batteries provide new solutions for achieving environmentally friendly and safe energy storage devices. Unfortunately, the further application is hampered by the growth of zinc dendrites caused by uneven zinc deposition, hydrogen evolution and other side interfacial reactions at the zinc anode. Herein, a multifunctional Bi‐Bi2O3 hybrid artificial interface layer is constructed on the surface of the zinc anode using an in situ conversion reaction. Among them, the Bi‐Bi2O3 Schottky structure not only significantly accelerates the migration of Zn2+ through its built‐in electric field, but also effectively improves the hydrogen evolution barrier (ΔGH*), thereby suppressing side reactions. Moreover, the Schottky contact formed between the interface layer and the metal zinc interface also regulates the electronic distribution state on the zinc surface and optimizes the deposition process of Zn2+, ensuring a more uniform and orderly zinc deposition process. Based on the synergistic effect of dual Schottky junctions, symmetric batteries achieve stable cycling for 2000 h under the conditions of 1.0 mA cm−2 and 1.0 mAh cm−2. The full cell assembled with α‐MnO2 as the cathode maintains capacity of 112.7 mAh g−1 after 1000 cycles at 1 A g−1 with a capacity retention rate of 84%.

"Anchoring Capture" Effect Mimicking Proline in Hardy Deep-Sea Fish to Stabilize the Zinc Anode with Lower Operating Temperature.

The low plating/stripping efficiency of zinc anodes, dendrite growth, and high freezing points of aqueous solutions hinder the practical application of aqueous zinc-ion batteries. This paper proposes a zwitterionic permeable network solid-state electrolyte based on the "anchor-capture" effect to address these problems by incorporating proline (Pro, a biological antifreeze agent) into the electrolyte. Extensive validation tests, Quantum Chemistry (QC) calculations, Molecular Dynamics (MD) Simulations, and ab initio molecular dynamics simulations consistently indicate that the amino groups in proline adsorb onto the Zn metal surface, stabilizing the zinc anode-electrolyte interface, suppressing side reactions from water decomposition, and homogenizing zinc-ion flux. This electrolyte demonstrates excellent reversibility in Zn-Mn2O3 cells and Zn-Zn half-cells, achieving a high coulombic efficiency of over 99.4% across 2000 cycles in Zn-Mn2O3 full cells, and delivering a discharge-specific capacity of 175.2 mAhg-1 at -35°C and 1 Ag-1. Additionally, an appropriate concentration of proline lowers the electrolyte's freezing point to -45°C through the network's solid-state effect, ensuring the stable operation of the solid-state battery at -35°C. This innovative concept of network solid-state electrolytes injects new vitality into the development of multifunctional solid-state electrolytes.

Cobalt nanoclusters Deposit on Nitrogen-Doped graphene Sheets as bifunctional electrocatalysts for high performance lithium – Oxygen batteries

Rechargeable lithium-oxygen (Li-O2) batteries are being considered as the next-generation energy storage systems due to their higher theoretical energy density. However, the practical application of Li-O2 batteries is hindered by slow kinetics and the formation of side products during the oxygen reduction and evolution reactions on the cathode. These reactions lead to high overpotentials during charging and discharging. To address these challenges, we propose a simple ultrasonic method for synthesizing cobalt nanoclusters embedded in nitrogen-doped graphene nanosheets (GrZnCo) derived from metal-organic frameworks (MOFs). The resulting material, due to the retention of metallic cobalt structure, exhibits better electronic conductivity. Additionally, the GrZnCo catalyst shows vigorous catalytic activity, which can improve reaction kinetics and suppress side reactions, thus lowering the charging overpotential. We have investigated the impact of different catalyst compositions (GrZnCox; x = 1, 3, 5) by varying the amounts of cobalt and zinc. The optimum catalyst, GrZnCo3, contains high cobalt-N active components, graphitic-N, pyridinic-N, pyrrolic-N, and abundant defect structures, which enhance the electrochemical performance. The defect-rich GrZnCo3 catalyst enables Li-O2 batteries to achieve a high discharge capacity of 13500 mAh·g−1 at 50 mA·g−1 and a remarkable long-term cycling performance of over 400 cycles at 100 mA·g−1 with a limited capacity of 500 mAh·g−1. This work demonstrates an effective approach to fabricate cost-effective electrocatalysts for various energy storage systems.

Multidentate Chelating Ligands Enable High‐Performance Zinc‐Bromine Flow Batteries

Zinc bromine flow battery (ZBFB) is a promising battery technology for stationary energy storage. However, challenges specific to zinc anodes must be resolved, including zinc dendritic growth, hydrogen evolution reaction, and the occurrence of "dead zinc". Traditional additives suppress side reactions and zinc dendrite formation by altering the solvation structure of Zn2+ and adsorbing onto the zinc surface through only a limited number of zincophilic sites, resulting in weak adsorption on zinc metal and potential inability to simultaneously optimize the solvation structure of zinc ions. Obviously, increasing the number of potential zincophilic sites in the additive can significantly enhance the interaction with zinc. Herein, we propose a strong chelate, ethylenediamine tetramethylene phosphonic acid (EDTMPA) as the additive, which boasts six potent zincophilic sites, not only promotes the formation of the water‐deficient inner Helmholtz plane but also plays a crucial role in restructuring the solvation environment of Zn2+. As a result, the zinc symmetric flow battery with EDTMPA exhibited exceptional coulombic efficiency of 99.4% over 800 cycles, surpassing the previous studies by a significant margin. Furthermore, the assembled ZBFB has showcased a dendrite‐free and enduring cycling over 400 cycles at 80 mA cm−2.

Zincophilic Sites Enriched Hydrogen-bonded Organic Framework as Multifunctional Regulating Interfacial Layers for Stable Zinc Metal Batteries.

To construct an efficient regulating layer for Zn anodes that can simultaneously address the issues of dendritic growth and side reactions is highly demanded for stable zinc metal batteries (ZMBs). Herein, we fabricate a hydrogen-bonded organic framework (HOF) enriched with zincophilic sites as a multifunctional layer to regulate Zn anodes with controlled spatial ion flux and stable interfacial chemistry (MA-BTA@Zn). The framework with abundant H-bonds helps capture H2O and remove the solvated shells on [Zn(H2O)6]2+, leading to suppressed side reactions. The HOF layer also helps form electrolyte-philic surfaces and expose Zn (002) crystal planes which benefit for rapid conduction and uniform deposition of Zn2+, and weakened sides reactions. Additionally, the electrochemically active zincophilic sites (C=O, -NH2 and triazine groups) favor the targeted guidance and penetration of Zn2+ and provide advantageous sites for uniform Zn deposition. High Young's modulus of the HOF layer further contributes to a high interfacial flexibility and stability against Zn plating-associated stress. The MA-BTA@Zn symmetric cells thereby obtain a substantially extended battery life over 1000 h at 4 mA cm-2. The MA-BTA@Zn||Cu half-cell demonstrates a highly reversible Zn stripping/plating process over 1500 cycles with impressive average Coulombic efficiency (CE) of 99.5% at 10 mA cm-2.

Zincophilic Sites Enriched Hydrogen‐Bonded Organic Framework as Multifunctional Regulating Interfacial Layers for Stable Zinc Metal Batteries

AbstractTo construct an efficient regulating layer for Zn anodes that can simultaneously address the issues of dendritic growth and side reactions is highly demanded for stable zinc metal batteries (ZMBs). Herein, we fabricate a hydrogen‐bonded organic framework (HOF) enriched with zincophilic sites as a multifunctional layer to regulate Zn anodes with controlled spatial ion flux and stable interfacial chemistry (MA‐BTA@Zn). The framework with abundant H‐bonds helps capture H2O and remove the solvated shells on [Zn(H2O)6]2+, leading to suppressed side reactions. The HOF layer also helps form electrolyte‐philic surfaces and expose Zn (002) crystal planes which benefit for rapid conduction and uniform deposition of Zn2+, and weakened sides reactions. Additionally, the electrochemically active zincophilic sites (C=O, −NH2 and triazine groups) favor the targeted guidance and penetration of Zn2+ and provide advantageous sites for uniform Zn deposition. High Young's modulus of the HOF layer further contributes to a high interfacial flexibility and stability against Zn plating‐associated stress. The MA‐BTA@Zn symmetric cells thereby obtain a substantially extended battery life over 1000 h at 4 mA cm−2. The MA‐BTA@Zn||Cu half‐cell demonstrates a highly reversible Zn stripping/plating process over 1500 cycles with impressive average Coulombic efficiency (CE) of 99.5 % at 10 mA cm−2.

Synthesis of Monodisperse and Discrete Ultra-High Nickel LiNi0.97Co0.02Mn0.01O2 Octahedral Single Crystals via Single Crystal Intermediates for Li-Ion Batteries.

Micrometer-sized single crystal cathodes have garnered significant interest as promising cathode materials for lithium-ion batteries due to their ability to reduce surface area exposure to electrolytes and suppress side reactions, thereby enhancing electrochemical performance. One of the challenging issues with single crystal cathode materials is synthesizing monodisperse and discrete single crystals rather than agglomerated quasi-single crystals. However, conventional solid-state synthesis of most single crystals results in severe agglomeration and cation mixing, as it requires high temperatures to promote particle growth to several micrometers. In this study, a novel morphology-conserving reaction strategy that employs octahedron single crystal intermediates is introduced to synthesize discrete, monodisperse LiNi0.97Co0.02Mn0.01O2 octahedron single crystals. This scalable and cost-effective approach involves using rock-salt Ni0.97Co0.02Mn0.01O1+x octahedrons as single crystal intermediates, which are transformed in unreactive unary lithium salt melts (LiCl and Li2SO4) from spherical Ni0.97Co0.02Mn0.01(OH)2 obtained via coprecipitation. These intermediates are then subjected to a stoichiometric amount of Li precursor in a conventional solid-state synthesis to produce layered LiNi0.97Co0.02Mn0.01O2. This process is a morphology-conserving lithiation reaction, leading to the formation of discrete and monodisperse LiNi0.97Co0.02Mn0.01O2 octahedron single crystals. The resultant LiNi0.97Co0.02Mn0.01O2 single crystals demonstrate superior electrochemical performance, including stable capacity retention over 150 cycles, which surpasses that of typical quasi-single crystals produced through conventional methods. This is attributed to negligible crack formation during cycling, in contrast to significant cracking observed in conventional quasi-single crystals. This implies that single-crystal forms are preferred over agglomerated quasi-single crystal forms for enhancing cycle performance. These findings provide valuable insights into the industrial synthesis of discrete and monodisperse ultrahigh-nickel oxide cathode materials.

Design Lithium Exchanged Zeolite Based Multifunctional Electrode Additive for Ultra‐High Loading Electrode Toward High Energy Density Lithium Metal Battery

AbstractThe practicalization of a high energy density battery requires the electrode to achieve decent performance under ultra‐high active material loading. However, as the electrode thickness increases, there is a notable restriction in ionic transport in the electrodes, limiting the diffusion kinetics of Li+ and the utilization rate of active substances. In this study, lithium‐ion‐exchanged zeolite X (Li‐X zeolite) is synthesized via Li+ exchange strategy to enhance Li+ diffusion kinetics. When incorporated Li–X zeolite into the ultra‐high loading cathodes, it possesses i) high electron conductivity with a uniform network by reducing tortuosity, ii) decent ion conductivity attributes to modulated Li+ diffusivity of Li‐X and iii) high elasticity to prevent particle‐level cracking and electrode‐level disintegration. Moreover, Li–X zeolite at the solid/liquid interface facilitates the formation of a stable cathode electrolyte interface, which effectively suppresses side reactions and mitigates the dissolution of transition cations. Therefore, an ultra‐high loading (66 mg cm−2) cathode is fabricated via dry electrode technology, demonstrating a remarkable areal capacity of 12.7 mAh cm−2 and a high energy density of 464 Wh kg−1 in a lithium metal battery. The well‐designed electrode structure with multifunctional Li–X zeolite as an additive in thick cathodes holds promise to enhance the battery's rate capability, cycling stability, and overall energy density.

Biphasic Production of 5-hydroxymethylfurfural (HMF) in a Recyclable Deep Eutectic Solvent-based System Catalyzed by H4SiW12O40.

The reaction with in situ extraction to yield 5-hydroxymethylfurfural (HMF) from d-fructose (Fru) was investigated using a biphasic system based on a self-consuming deep eutectic solvent (DES) as reaction phase. The significance of choline chloride (ChCl), a cost-effective and safe quaternary ammonium salt, was evident in enhancing HMF yield through fructose dehydration and concurrently suppressing side reactions. The DES system demonstrated fast reactions with high selecivities and recyclability across five cycles. The observed decline in H4SiW12O40 activity, primarily due to proton leaching, was successfully restored with the addition of HCl. Furthermore, ChCl exhibited ease of recrystallization in the presence of acetonitrile. This research proposes an environmentally friendlier approach for HMF production through a reusable-biphasic process. The presented reaction system suppresses completely the formation of levulinic and formic acid leading to HMF yields of up to 84 % of selectivities of up to 88 % after 30 minutes at 80 °C. The system was recycled over 16 runs and after an initial slight loss of activity the system in the run 0-5, run 6-15 has shown a constant HMF output as in the first recycling run.

A small amount of sodium difluoro(oxalate)borate additive induces anion-derived interphases for sodium-ion batteries

In sodium-ion batteries, the properties of the electrode-electrolyte interphases (EEIs) layer formed on the electrode surface, dominate the Na+ de-solvation process and Na+ (de)intercalation behavior, thereby influencing the battery performance. Currently, both high-concentration electrolytes and localized high-concentration electrolytes facilitate the formation of anion-derived and inorganic-rich interfacial chemistry, leading to excellent electrochemical performance. However, the expensive lithium salt and/or fluorinated diluent imposes a major concern. Herein, a small amount additive of 0.5 wt% sodium difluoro(oxalate)borate (NaDFOB) with the electron-rich property is introduced into 1 mol L–1 NaClO4/propylene carbonate electrolyte to construct a robust inorganic-rich EEIs via an anion preferential adsorption-decomposition mechanism. Theoretical calculations and experimental results reveal that the DFOB– anion has a lower adsorption energy than the other components, which will be preferentially adsorbed in the inner Helmholtz plane (IHP) with the closer proximity to two electrode surfaces and thus being firstly decomposed to form inorganic-rich interphases, thereby effectively suppressing side reactions. Consequently, both Na-ion half-cells and full-cells using this electrolyte deliver excellent cycling performance. This strategy that regulates the interphase chemistry on the electrode surface through an anion preferential adsorption-decomposition strategy, provides a promising avenue for developing long-term cycling sodium-ion batteries.

Synthesis of well-defined poly(p-alkoxystyrene) by anionic polymerization in the presence of di-n-butylmagnesium

This study demonstrates the necessity of introducing di-n-butylmagnesium (n-Bu2Mg) additives to synthesize precisely controlled polymers through anionic polymerization of p-alkoxystyrene monomers at −40 °C. Without additives, 4-tert-butoxystyrene (BSt) and 4-(1-ethoxy ethoxy) styrene (EESt) are polymerized using sec-butyllithium (s-BuLi) in tetrahydrofuran (THF) solvent, yielding a molecular weight distribution (MWD) of 1.36. However, the MWD is strictly controlled to 1.05–1.06 after adding n-Bu2Mg in more than 30 times the amount of s-BuLi, resulting in an accurately designed molecular weight. Therefore, n-Bu2Mg effectively suppresses side reactions that could occur at the polymerization temperature of −40 °C in the Schlenk reactor. Interestingly, the polymerization reaction of styrene monomer proceeds when n-Bu2Mg is mixed in THF solvent at −40 °C for an extended period, even without s-BuLi. This result suggests that, despite being a weak anionic initiator, n-Bu2Mg can initiate polymerization due to the lower electron density of the styrene double bond compared to BSt or EESt. Based on these results, a precise copolymer with a narrow molecular weight distribution can be synthesized by initiating polymerization with s-BuLi within 20 s of adding n-Bu2Mg to the mixed monomers of styrene and EESt.

Localized High-Concentration Electrolyte in Li-Mediated Nitrogen Reduction for Ammonia Synthesis.

The lithium-mediated nitrogen reduction reaction (Li-NRR) is a promising green alternative to the Haber-Bosch process for ammonia synthesis. The solid electrolyte interphase (SEI) is crucial for high efficiency and stability, as it regulates reactant diffusion and suppresses side reactions. The SEI properties are greatly influenced by the Li+ ion solvation structure, which is controllable through electrolyte engineering. Although anion-derived SEI enhances selectivity and stability, it has typically been engineered using high-concentration electrolytes (HCEs), which face mass transfer, viscosity, and cost issues. In this study, a localized high-concentration electrolyte (LHCE) in the Li-NRR is first introduced, enabling the formation of anion-derived SEI in a low-concentration electrolyte (LCE) by enhancing the Li-anion coordination using an antisolvent. Among various antisolvents, 1,1,2,2-tetrafluoroethyl-2,2,3,3-tetrafluoropropyl ether (TTE) achieves the highest ammonia Faradaic efficiency (73.6 ± 2.5%), more than double that of the LCE (34.3 ± 2.8%) and exceeding the HCE (56.0 ± 2.8%). Systematic calculations and experimental analyses show that the LHCE exhibits anion-rich solvation structures and formsthin, inorganic SEI. Moreover, the LHCE has advantages of low viscosity and high N2 solubility, which facilitate mass transport. This study suggests the application of LHCE as an effective electrolyte engineering strategy to enhance the Li-NRR efficiency.

Constructing Cyclic Hydrogen Bonding to Suppress Side Reactions and Dendrite Formation on Zinc Anodes.

The high electrochemical reactivity of H2O molecules and zinc metal results in severe side reactions and dendrite formation on zinc anodes. Here we demonstrate that these issues can be addressed by using N-hydroxymethylacetamide (NHA) as additives in 2 M ZnSO4 electrolytes. The addition of NHA molecules, acting as both a hydrogen bond donor and acceptor, enables the formation of cyclic hydrogen bonding with H2O molecules. This interaction disrupts the existing hydrogen bonding networks between H2O molecules, hindering proton transport, and containing H2O molecules within the cyclic hydrogen bonding structure to prevent deprotonation. Additionally, NHA molecules show a preference for adsorption on the (101) crystal surface of zinc metal. This preferential adsorption reduces the surface energy of the (101) plane, facilitating the homogeneous Zn deposition along the (101) direction. Thus, the NHA enables Zn||Zn symmetric cell with a cycle lifespan of 1100 hours at 5 mA cm-2 and Zn||Cu asymmetric cell with a high Coulombic efficiency over 99.5 %. Moreover, the NHA-modified Zn||AC zinc ion hybrid capacitor is capable of sustaining 15000 cycles at 2 A g-1. This electrolyte additive engineering presents a promising strategy to enhance the performance and broaden the application potential of zinc metal-based energy storage devices.

Formulating Self-Repairing Solid Electrolyte Interface via Dynamic Electric Double Layer for Practical Zinc Ion Batteries.

Zinc ion batteries (ZIBs) encounter interface issues stemming from the water-rich electrical double layer (EDL) and unstable solid-electrolyte interphase (SEI). Herein, we propose the dynamic EDL and self-repairing hybrid SEI for practical ZIBs via incorporating the horizontally-oriented dual-site additive. The rearrangement of distribution and molecular configuration of additive constructs the robust dynamic EDL under different interface charges. And, a self-repairing organic-inorganic hybrid SEI is constructed via the electrochemical decomposition of additive. The dynamic EDL and self-repairing SEI accelerate interfacial kinetics, regulate deposition and suppress side reactions in the both stripping and plating during long-term cycles, which affords high reversibility for 500 h at 42.7 % depth of discharge or 50 mA ⋅ cm-1. Remarkably, Zn//NVO full cells deliver the impressive cycling stability for 10000 cycles with 100 % capacity retention at 3 A ⋅ g-1 and for over 3000 cycles even at lean electrolyte (7.5 μL ⋅ mAh-1) and high loading (15.26 mg ⋅ cm-2). Moreover, effectiveness of this strategy is further demonstrated in the low-temperature full cell (-30 °C).

Bi-Functional Interfacial Modification Enables Highly-Exposed Zn(002) Crystal Facet Towards Durable Zn Metal Batteries.

Zn-ion batteries (ZIBs) have garnered growing interest in large-scale energy storage devices for the high safety, high theoretical capacity and low electrochemical potential. Nevertheless, their widespread applications are significantly impeded by dendrite formation, hydrogen evolution and corrosion reactions of Zn anodes. Herein, a bi-functional polyacrylic acid (PAA) modified-Zn anode (Zn-PAA) is designed to concurrently inhibit Zn dendrite formation and alleviate side reactions for durable ZIBs. The bi-functional PAA coating not only selectively acid-etches the active Zn crystal facets to guide the planar deposition along the highly-exposed Zn(002) crystal facet, but also facilitate uniform Zn deposition through coordination between the polymer functional groups and Zn2+. Meanwhile, the electrically-insulated PAA protective layer effectively separates Zn anodes from the electrolyte and modulates the solvation structure of Zn2+.6H2O, significantly suppressing side reactions. Consequently, the assembled Zn-PAA//Zn-PAA symmetrical cell delivers an outstanding cycling stability of 1600 h at 1 mA cm-2 and 1 mAh cm-2. The assembled KVO//Zn-PAA full cell shows exceptional cycling stability over 1500 cycles at 2.0 A g-1 with a high Coulombic efficiency approaching 100 %. The facile bi-functional surface modification strategy, which enables to finely tune the crystal facet texture and ion distribution manner, opens up a groundbreaking path towards safe and durable ZIBs.

Study on an Interpenetrating Artificial SEI for Lithium Metal Anode Modification and Fast Charging Characterization.

Artificial SEI is one of the effective strategies to improve lithium dendrites and suppress side reactions. However, the role of SEI components and distribution on the modification of the lithium metal anode remains unclear. Therefore, in this study, the oxygen-sulfur (O-S) component and its distribution in SEI were modulated by designing experiments, and then the mechanism of its action was deeply investigated. The study is based on an in-depth analysis of the properties of lithium sulfide (Li2S) and lithium oxide (Li2O) as SEI layer materials and effectively combines them in an ether electrolyte environment to form an innovative SEI structure. The experimental results show that the optimal SEI modulation condition is O120-S10. O120-S10 significantly improves the kinetic performance of electrochemical reactions, reduces the film resistance, and achieves cycling stability of up to 2100 h during high-capacity lithium deposition/stripping at 5 mAh cm-2. When used in conjunction with a ternary cathode material (NCM811), the O120-S10 demonstrates excellent performance under high rate charge/discharge conditions at 10C. After 1500 cycle tests, the battery's specific capacity was maintained at 90 mAh g-1 and the Coulombic efficiency reached 98.52%. Through X-ray photoelectron spectroscopy (XPS) analysis, the vertical structure and ratio distribution of components in SEI were revealed in detail, and the optimal component ratios of Li2S 46.48%, Li2O 46.02%, and Li2CO3 7.50% were determined. The mechanism of action is to achieve a 1 + 1 > 2 superlinear synergistic effect and fast charging performance by combining the ability of Li2O's low lithium ion diffusion barrier with Li2S's ability to inhibit the growth of lithium dendrites.