Interfacial Reaction Kinetics Research Articles

Boosting K-ion kinetics by interfacial polarization induced by amorphous MoO3- for MoSe2/MoO3-@rGO composites

Ø The K-ion storage of MoSe 2 @rGO is enhanced by incorporating amorphous MoO 3- x with oxygen vacancies. Ø A built-in electric field benefits for electron-transfer and K-ion migration across the hetero-junction interface. Ø Larger dielectric polarization induced by MoO 3- x reduces charge transfer resistance and enhance K-ion migration across electric double-layer. Promoting interfacial reaction kinetics is highly desirable for achieving high-performances of anode material in alkali-ion batteries. Herein, flower-like MoSe 2 /MoO 3- x @rGO composites are fabricated by a facile solvothermal method involving a thermal-treatment at 800°C. When evaluated as an anode material for potassium ion batteries, MoSe 2 /MoO 3- x @rGO delivers 248.2 mA h g −1 after 50 cycles at 0.2 A g −1 with a capacity retention of 84.6% and 182.9 mA h g −1 after 150 cycles at 1.0 A g −1 with a capacity retention of almost 61.2%, superior to those of bare MoSe 2 or MoSe 2 @rGO composites. Analysis from electrochemical measurements, the amorphous MoO 3- x containing oxygen vacancies could not only effectively buffer the self-aggregation of MoSe 2 nanosheets but also provides lots of accessible active sites for potassium ion storage. Additionally, the open channels in the amorphous MoO 3- x phase lead to easier ion hopping and smaller diffusion barriers. Furthermore, the built-in electric field at the interface would be beneficial for electron transfer and K-ion migration across the hetero-junction interface. Moreover, larger dielectric polarization induced by the high relative permittivity of amorphous MoO 3- x would reduce charge transfer resistance and enhance K-ion migration across electric double-layer. Our work provides new insight into the enhanced performance of anode material coated by an amorphous layer with large relative permittivity.

Hollow nanorods MoS2@SnS heterojunction for sodium storage with enhanced cyclic stability

• 2D stannous sulfide nanosheets coated molybdenum disulfide nanotube constructed hierarchical nanostructure is obtained by using conventional template method. • The specific discharge capacity reaches up to 819 mA g −1 , and the initial coulombic efficiency is 81.8%. • The discharge capacity is maintained at 430.7 mAh g −1 with decay of only 7.2% after 300 cycles at 1000 mA g −1 . Coupling the composite electrodes formed by two different semiconductors is an effective way to enhance the charge transfer rate and interfacial reaction kinetics of electrodes. In this work, two-dimensional stannous sulfide nanosheets (SnS) coated molybdenum disulfide (MoS 2 ) nanotube constructed hierarchical nanostructure is obtained by using conventional template method, and the battery properties are studied in detail. The specific discharge capacity of the composite material reaches up to 819 mAh g −1 , and the initial coulombic efficiency (CE) is 81.8% at first cycle. The discharge capacity is maintained at 430.7 mAh g −1 with decay of only 7.2% after 300 cycles at 1000 mA g −1 . These impressive discharge properties may be related to the designed layered structure that accelerates the separation and transfer rate of ions and electrons at the electrode interface. The unique hierarchical structure can also provide abundant reaction binding sites, buffer the electrode volume change, and thus enhance the sodium storage performance.

All‐Solid‐State Li–S Batteries Enhanced by Interface Stabilization and Reaction Kinetics Promotion through 2D Transition Metal Sulfides

AbstractAll‐solid‐state lithium‐sulfur batteries (ASSLSBs) based on sulfide solid‐state electrolytes (SSEs) provide prospectively high energy density and safety. However, the low conductivity and sluggish reaction kinetic of sulfur cathode limit its commercialization. The use of carbon additives can improve the electrical conductivity but accelerates the decomposition of SSEs. Herein, a highly conductive carbon fiber decorated with hybrid 1T/2H MoS2 nanosheets is designed. The high chemical and electrochemical compatibility among MoS2 and sulfide SSE can greatly improve the stability of the cathode and therefore maintain pristine interfaces. The uniform distribution of electrical‐conductive metallic 1T MoS2 on carbon fiber benefits the electron transfer between carbon and sulfur. Meanwhile, the layered structure of MoS2 can be intercalated by a large amount of Li ions facilitating ionic and electronic conductivity. In consequence, the charge transfer and reaction kinetics are greatly enhanced, and the decomposition of SSEs is successfully relieved. As a result, the ASSLSB delivers an ultrahigh initial discharge and charge capacity of 1456 and 1470 mAh g−1 at 0.05 C individually with ultrahigh coulombic efficiency and maintains high capacity retention of 78% after 220 cycles. The batteries also obtain a remarkable rate performance of 1069 mAh g−1 at 1 C.

Achieving high-energy-density magnesium/sulfur battery via a passivation-free Mg-Li alloy anode

Magnesium/sulfur batteries have emerged as one of the considerable choices for next-generation batteries. However, its low voltage platform caused by the passivation of magnesium anode limits its actual energy density. Herein, a magnesium-lithium alloy is screened out as a passivation-free anode, which hinders the passivation reaction on the anode through the substitution reaction between lithium in the alloy and the magnesium ions in the electrolyte. The alloy anode exhibits an improved interfacial reaction kinetics, and the impedance is reduced by 5 orders of magnitude compared to that of magnesium anode. With passivation-free Mg-Li alloy anode, the magnesium/sulfur battery achieves an enhanced discharge voltage platform of 1.5 V and an energy density of 1829 Wh kg−1. This study provides a novel design of passivation-free magnesium alloy anode for high-energy-density magnesium/sulfur batteries.

Enhanced immobilization and accelerated conversion of polysulfides by functionalized separator for advanced lithium sulfur batteries

Lithium-sulfur (Li–S) batteries have attracted much attention due to high energy density and low cost. However, some vital issues, especially the notorious shuttle effect of polysulfides has greatly hindered the practical development of Li–S batteries. Reasonable design of electrocatalysts to improve the electrochemical performance of Li–S batteries by enhancing the chemical immobilization and catalytic conversion of polysulfides is considered as a promising solution. Herein, an integrated structure consisting of reduced graphene oxide (RGO) nanosheets modified with Co9S8 nanoparticles is reported, which is expected to be used as a mediator for Li–S batteries to improve the anchoring and catalyzing of polysulfides. The Co9S8 nanoparticles not only have excellent chemisorption capability to capture polysulfides, but also can be used as catalysts to accelerate the conversion of polysulfides. Highly conductive RGO nanosheets can provide appropriate ion/electron diffusion path length, facilitate interfacial reaction kinetics and physically limit polysulfide diffusion. Accordingly, the as-assembled Li–S battery has excellent cycling stability with a low capacity decay rate of 0.041% per cycle over 1000 cycles at 3 A g−1. Importantly, it enables the device to operate over a wide temperature range, with an area specific capacity of 6.4 mAh cm−2 at a sulfur load of 5.8 mg cm−2.

Construction of Bio-inspired Film with Engineered Hydrophobicity to Boost Interfacial Reaction Kinetics of Aqueous Zinc-Ion Batteries.

Aqueous zinc-ion batteries typically suffer from sluggish interfacial reaction kinetics and drastic cathode dissolution owing to the desolvation process of hydrated Zn2+ and continual adsorption/desorption behavior of water molecules, respectively. To address these obstacles, a bio-inspired approach, which exploits the moderate metabolic energy of cell systems and the amphiphilic nature of plasma membranes, is employed to construct a bio-inspired hydrophobic conductive poly(3,4-ethylenedioxythiophene) film decorating α-MnO2 cathode. Like plasma membranes, the bio-inspired film can "selectively" boost Zn2+ migration with a lower energy barrier and maintain the integrity of the entire cathode. Electrochemical reaction kinetics analysis and theoretical calculations reveal that the bio-inspired film can significantly improve the electrical conductivity of the electrode, endow the cathode-electrolyte interface with engineered hydrophobicity, and enhance the desolvation behavior of hydrated Zn2+ . This results in an enhanced ion diffusion rate and minimized cathode dissolution, thereby boosting the overall interfacial reaction kinetics and cathode stability. Owing to these intriguing merits, the composite cathode can demonstrate remarkable cycling stability and rate performance in comparison with the pristine MnO2 cathode. Based on the bio-inspired design philosophy, this work can provide a novel insight for future research on promoting the interfacial reaction kinetics and electrode stability for various battery systems.

Hydrophobization Engineering of the Air–Cathode Catalyst for Improved Oxygen Diffusion towards Efficient Zinc–Air Batteries

AbstractPoor oxygen diffusion at multiphase interfaces in an air cathode suppresses the energy densities of zinc–air batteries (ZABs). Developing effective strategies to tackle the issue is of great significance for overcoming the performance bottleneck. Herein, inspired by the bionics of diving flies, a polytetrafluoroethylene layer was coated on the surfaces of Co3O4 nanosheets (NSs) grown on carbon cloth (CC) to create a hydrophobic surface to enable the formation of more three‐phase reaction interfaces and promoted oxygen diffusion, rendering the hydrophobic‐Co3O4 NSs/CC electrode a higher limiting current density (214 mA cm−2 at 0.3 V) than that (10 mA cm−2) of untreated‐Co3O4 NSs/CC electrode. Consequently, the assembled ZAB employing hydrophobic‐Co3O4 NSs/CC cathode acquired a higher power density (171 mW cm−2) than that (102 mW cm−2) utilizing untreated‐Co3O4 NSs/CC cathode, proving the enhanced interfacial reaction kinetics on air cathode benefiting from the hydrophobization engineering.

Hydrophobization Engineering of the Air-Cathode Catalyst for Improved Oxygen Diffusion towards Efficient Zinc-Air Batteries.

Poor oxygen diffusion at multiphase interfaces in an air cathode suppresses the energy densities of zinc-air batteries (ZABs). Developing effective strategies to tackle the issue is of great significance for overcoming the performance bottleneck. Herein, inspired by the bionics of diving flies, a polytetrafluoroethylene layer was coated on the surfaces of Co3 O4 nanosheets (NSs) grown on carbon cloth (CC) to create a hydrophobic surface to enable the formation of more three-phase reaction interfaces and promoted oxygen diffusion, rendering the hydrophobic-Co3 O4 NSs/CC electrode a higher limiting current density (214 mA cm-2 at 0.3 V) than that (10 mA cm-2 ) of untreated-Co3 O4 NSs/CC electrode. Consequently, the assembled ZAB employing hydrophobic-Co3 O4 NSs/CC cathode acquired a higher power density (171 mW cm-2 ) than that (102 mW cm-2 ) utilizing untreated-Co3 O4 NSs/CC cathode, proving the enhanced interfacial reaction kinetics on air cathode benefiting from the hydrophobization engineering.

Microgroove-patterned Zn metal anode enables ultra-stable and low-overpotential Zn deposition for long-cycling aqueous batteries

The application of zinc (Zn) metal in aqueous Zn metal batteries (ZMBs) has been hindered by the susceptibility of Zn anodes to dendritic electrodeposition due to its inhomogeneous surface structures. Herein, we design uniform microgroove patterns on practically accessible Zn foil anodes using a simple and scalable acid etching strategy. The unique surface structure guides homogeneous Zn deposition, accelerates interfacial reaction kinetics, and inhibits electrolyte corrosion. The resulting Zn anodes afford an excellent plating/stripping stability of 2920 h at an ultralow overpotential of 19.5 mV under 1 mA cm−2/1 mAh cm−2 cycling, with both the cycle life and overpotential ranking among the best records reported thus far. Moreover, the synergetic mechanisms for morphology-induced enhancement were rigorously elucidated. The present strategy contributes a reliable performance baseline for future studies, and can be readily combined with other emerging tactics such as surface coating to accelerate further performance upgrades towards practical ZMBs.

Rapid Electrochemical Activation of V2O3@C Cathode for High‐Performance Zinc‐Ion Batteries in Water‐in‐Salt Electrolyte

Aqueous Zn-ion batteries (ZIBs), with the advantages of low cost, high safety, and high capacity, have great potential for application in grid energy storage and wearable flexible devices. However, their commercial application is still restricted by their inferior long-term cycling stability, Zn dendrite formation, and the decomposition of aqueous electrolyte. In this study, a Zn|Zn(CF3 SO3 )2 +LiTFSI|V2 O3 @C cell is constructed to address the above issues. The V2 O3 @C electrode can be fully oxidized into amorphous V2 O5 @C simultaneously with Zn2+ and H2 O co-insertion. The cell delivers a high specific capacity of more than 240 mAh g-1 at 3 A g-1 , with extraordinary coulombic efficiency and capacity retention. The excellent electrochemical performances are attributed to synergistic effects between the V2 O3 @C electrode and the water-in-salt electrolyte with enhanced stability and improved interface reaction kinetics. Systematic improvements of this architecture indicate much promise for application.

Damage investigations of the rebar under the coupling effect of fatigue and stray electric field induced corrosion

The damage mechanism of RC infrastructures due to the coupling effect of corrosion-fatigue has not yet been fully revealed. This paper devoted to investigating the damage characteristics of rebars under the coupling effect of stray electric field induced corrosion and axial force-controlled fatigue. Firstly, the detail of simulated concrete pore solution species was determined by thermodynamic calculations. Subsequently, the interfacial reaction kinetics was extracted via the electrochemical methods and fitting approaches. Ultimately, we exhibited the damage deformation process and the macro-morphology of fracture surfaces of rebars. In addition, an ia-rmax-Nf projection surface for evaluating the corrosion-fatigue life of rebars was proposed.

Interfacial Phenomena and Reaction Kinetics between High Al Molten Steel and CaO-SiO2-Type Flux

To understand the reaction mechanism between high Mn-high Al steel and slag, the reaction experiment of Fe-Mn-Al melts with CaO-SiO2-type flux was carried out in MgO crucible at 1873 K. The evolution of the morphology of interface was inspected firstly, and then the global reaction kinetics was modeled in consideration of the effect of dynamic interfacial phenomena. The results show that in the reaction of Fe-5 mass % Al alloy with high SiO2 or low SiO2 protective slag, the strong chemical affinity between the metal and flux leads to strong spontaneous emulsification and attenuated with the progression of the reaction. Combined with the change of interfacial area caused by emulsification, it is found that the global reaction kinetics can be described satisfactorily by the mass transfer model of Al in liquid steel, and the determined mass transfer coefficient was about k[Al]=4.46×10−5 m/s. However, the emulsification phenomenon in the reaction of Fe-13%Mn-5%Al alloy with low SiO2 slag did not disappear with the reaction, which can be attributed to the decreasing of the interfacial tension with Mn addition and the accumulation of C on the interface. This reaction process can be modeled by assuming the mass transfer of SiO2 in the slag as the rate-controlling step with the estimated transfer coefficient of k(SiO2)=5.12×10−6 m/s.

Tunable metal contacts at layered black-arsenic/metal interface forming during metal deposition for device fabrication

Understanding the kinetics of interfacial reaction in the deposition of metal contacts on 2D materials is important for determining the level of contact tenability and the nature of the contact itself. Here, we find that some metals, when deposited onto layered black-arsenic films using e-beam evaporation, form a-few-nm thick distinct intermetallic layer and significantly change the nature of the metal contact. In the case of nickel, the intermetallic layer is Ni11As8, whereas in the cases of chromium and titanium they are CrAs and a-Ti3As, respectively, with their unique structural and electronic properties. We also find that temperature, which affects interatomic diffusion and interfacial reaction kinetics, can be used to control the thickness and crystallinity of the interfacial layer. In the field effect transistors with black-arsenic channel, due to the specifics of its formation, this interfacial layer introduces a second and more efficient edge-type charge transfer pathway from the metal into the black-arsenic. Such tunable interfacial metal contacts could provide new pathways for engineering highly efficient devices and device architectures.

Direct Visualization of Dynamic Mobility of Li2O2 in Li-O2 Batteries: A Differential Interference Microscopy Study.

The reversibility and the discharge/charge performance in nonaqueous lithium-oxygen (Li-O2) batteries are critically dependent on the kinetics of interfacial reactions. However, the interfacial reaction dynamic behaviors, especially the quantitative analysis, are still far from deep understanding. Using the method of laser confocal microscopy combined with differential interference contrast microscopy (LCM-DIM), we monitored the Li-O2 interfacial reaction and in situ traced the Li2O2 migration processes promoted by the solution catalyst. Different dynamic behaviors exist when regulating the concentration of the redox mediator. Quantitative analysis of the discharged Li2O2 particles shows high mobility at the early discharge stage and decayed motion in the subsequent process, indicating the solution-mediated pathway participating Li2O2 formation in the low-concentration redox mediator addition, while particles/aggregates confined into the amorphous film demonstrate simultaneous solution and surface route-mediated pathway participation in the high-concentration case. These distinctive observations of Li2O2 formation and decomposition processes present the advantage of LCM-DIM to fundamentally understand the dynamic evolution in Li-O2 batteries.

Core-Shell ZIF-67@ZIF-8-derived multi-dimensional cobalt-nitrogen doped hierarchical carbon nanomaterial for efficient oxygen reduction reaction

Fuel cells have emerged as a charming candidate for next-generation energy conversion devices. However, it is highly desired but challenging to engineer advanced non-precious oxygen reduction catalysts with highly actives and stability due to the sluggish kinetics of oxygen reduction reaction (ORR) on fuel cell cathode. Herein, a novel hybrid architecture with Co nanoparticles embedded in N-doped carbon nanotubes and hollow nanocarbon polyhedron (Co@N-CNT-HC) was constructed from core-shell ZIF-67@ZIF-8 via a facile epitaxial growth-pyrolysis process. With the Co@N-CNT-HC as the catalyst, a remarkable ORR performance is achieved in terms of a high half-wave potential of 0.84 V, a large limiting current density of 4.70 mA/cm2, and excellent long-term durability ( 97.8% current retention after 8 h) in alkaline medium, which outperform commercial Pt/C catalyst. Further dynamic calculations indicated that ORR follows a four-electron reaction mechanism. The enhancement activity of Co@N-CNT-HC is mainly due to the effective integration of 0D Co nanoparticles, 1D carbon nanotubes and 3D hollow nanocarbon, which synergistically strengthen the interfacial reaction kinetics of oxygen and accelerate mass/charge transfer. The strategy reported in this work provides a new insight to synthesis of low-cost and well-designed carbon hybrid electrocatalyst for ORR.

Interfacial engineering of transition-metal sulfides heterostructures with built-in electric-field effects for enhanced oxygen evolution reaction

• The MoS 2 /NiS 2 and WS 2 /NiS 2 heterostructures are synthesized by a facile solid-state synthesis strategy. • The obtained heterostructures spontaneously construct a built-in electric field at the heterointerface. • The MoS 2 /NiS 2 and WS 2 /NiS 2 heterostructures exhibit superior OER performance. Developing highly efficient, durable, and non-noble electrocatalysts for the sluggish anodic oxygen evolution reaction (OER) is the pivotal for meeting the practical demand in water splitting. However, the current transition-metal electrocatalysts still suffer from low activity and durability on account of poor interfacial reaction kinetics. In this work, a facile solid-state synthesis strategy is developed to construct transition-metal sulfides heterostructures (denoted as MS 2 /NiS 2 , M = Mo or W) for boosting OER electrocatalysis. As a result, MoS 2 /NiS 2 and WS 2 /NiS 2 show lower overpotentials of 300 mV and 320 mV to achieve the current density of 10 mA·cm −2 , and smaller Tafel slopes of 60 mV·dec −1 and 83 mV·dec −1 in 1 mol·L −1 KOH, respectively, in comparison with the single MoS 2 , WS 2 , NiS 2 , as well as even the benchmark RuO 2 . The experiments reveal that the designed heterostructures have strong electronic interactions and spontaneously develop a built-in electric field at the heterointerface with uneven charge distribution based on the difference of band structures, which promote interfacial charge transfer, improve absorptivity of OH − , and modulate the energy level more comparable to the OER. Thus, the designed transition-metal sulfides heterostructures exhibit a remarkably high electrocatalytic activity for OER. This study provides a simple strategy to manipulate the heterostructure interface via an energy level engineering method for OER and can be extended to fabricate other heterostructures for various energy-related applications.

Decoupled Measurement and Modeling of Interface Reaction Kinetics of Ion-Intercalation Battery Electrodes

Ultrahigh rate performance of active particles used in lithium-ion battery electrodes has been revealed by single-particle measurements, which indicates a huge potential for developing high-power batteries. However, the charging/discharging behaviors of single particles at ultrahigh C-rates can no longer be described by the traditional electrochemical kinetics in such ion-intercalation active materials. In the meantime, regular kinetic measuring methods meet a challenge due to the coupling of interface reaction and solid-state diffusion processes of active particles. Here, we decouple the reaction and diffusion kinetics via time-resolved potential measurements with an interval of 1 ms, revealing that the classical Butler-Volmer equation deviates from the actual relation between current density, overpotential, and Li+ concentration. An interface ion-intercalation model is developed which considers the excess driving force of Li+ (de)intercalation in the charge transfer reaction for ion-intercalation materials. Simulations demonstrate that the proposed model enables accurate prediction of charging/discharging at both single-particle and electrode scales for various active materials. The kinetic limitation processes from single particles to composite electrodes are systematically revealed, promoting rational designs of high-power batteries.

Electro-catazone treatment of ozone-resistant drug ibuprofen: Interfacial reaction kinetics, influencing mechanisms, and degradation sites

Electro-heterogeneous catalytic ozonation (E-catazone) is a promising advanced oxidation process using a unique TiO2 nanoflower (TiO2-NF)-coated porous Ti anode. This study investigated interfacial reaction kinetics and the influencing mechanism of E-catazone degrading ozone-resistant drug ibuprofen. An elementary reactions library of the E-catazone process was established. The kinetic rate of key interfacial reactions under different operation parameters was quantitatively resolved. It was found that parameters such as current, initial pH, O3 concentration, and flowrate mainly affect •OH formation and ibuprofen removal via influencing three key interfacial reactions including anodic TiO2-NF surface hydroxylation, subsequent TiO2-NF‒OH/O3 heterogeneous catalysis, and cathodic generation of H2O2. In addition, the degradation pathways and sites of ibuprofen were also predicted via theoretical chemistry calculation, showing that •OH attacked C(12), C(11), or C(6) atom of the benzene ring in the ibuprofen via a radical adduct formation pathway. The results of this study will guide the application of the E-catazone process in the efficient removal of ozone-resistant drugs.

Achieving High-Performance 3D K+ -Pre-intercalated Ti3 C2 Tx MXene for Potassium-Ion Hybrid Capacitors via Regulating Electrolyte Solvation Structure.

The development of high-performance anode materials for potassium-based energy storage devices with long-term cyclability requires combined innovations from rational material design to electrolyte optimization. A three-dimensional K+ -pre-intercalated Ti3 C2 Tx MXene with enlarged interlayer distance was constructed for efficient electrochemical potassium-ion storage. We found that the optimized solvation structure of the concentrated ether-based electrolyte leads to the formation of a thin and inorganic-rich solid electrolyte interphase (SEI) on the K+ -pre-intercalated Ti3 C2 Tx electrode, which is beneficial for interfacial stability and reaction kinetics. As a proof of concept, 3D K+ -Ti3 C2 Tx //activated carbon (AC) potassium-ion hybrid capacitors (PIHCs) were assembled, which exhibited promising electrochemical performances. These results highlight the significant roles of both rational structure design and electrolyte optimization for highly reactive MXene-based anode materials in energy storage devices.

Achieving High‐Performance 3D K+‐Pre‐intercalated Ti3C2Tx MXene for Potassium‐Ion Hybrid Capacitors via Regulating Electrolyte Solvation Structure

AbstractThe development of high‐performance anode materials for potassium‐based energy storage devices with long‐term cyclability requires combined innovations from rational material design to electrolyte optimization. A three‐dimensional K+‐pre‐intercalated Ti3C2Tx MXene with enlarged interlayer distance was constructed for efficient electrochemical potassium‐ion storage. We found that the optimized solvation structure of the concentrated ether‐based electrolyte leads to the formation of a thin and inorganic‐rich solid electrolyte interphase (SEI) on the K+‐pre‐intercalated Ti3C2Tx electrode, which is beneficial for interfacial stability and reaction kinetics. As a proof of concept, 3D K+‐Ti3C2Tx//activated carbon (AC) potassium‐ion hybrid capacitors (PIHCs) were assembled, which exhibited promising electrochemical performances. These results highlight the significant roles of both rational structure design and electrolyte optimization for highly reactive MXene‐based anode materials in energy storage devices.