Structural Evolution Process Research Articles

Water-Lubricated Aluminum Vanadate for Enhanced Rechargeable Magnesium Ion Storage.

Magnesium ion batteries (MIBs) have attracted much attention due to their low cost and high safety properties. However, the intense charge repulsion effect and sluggish diffusion dynamics of Mg2+ ions result in unsatisfactory electrochemical performance of conventional cathode materials in MIBs. This work reports water-lubricated aluminum vanadate (HAlVO) as high-performance cathode material for Mg2+ ions storage and investigates the capacity fade mechanism of water-free aluminum vanadate (AlVO). The charge density difference based on density functional theory calculation is performed to analyze the charge transfer process of water-lubricated/free aluminum vanadates (HAlVO/AlVO). The different charge transfer phenomena of two materials and the charge shielding effect of water molecule in HAlVO are revealed. Moreover, the single-phase structural evolution process and the Mg2+ ions storage mechanism of HAlVO are further investigated deeply by different in situ and ex situ characterization methods. This work proves that HAlVO is a potential candidate cathode material to satisfy the high-performance reversible Mg2+ ions storage, and the water-lubricated method is an effective strategy to improve the electrochemical performance of vanadium oxides cathode.

Glycerol steam reforming over hydrothermal synthetic Ni-Ca/attapulgite for green hydrogen generation

• Glycerol steam reforming over hydrothermal synthetic Ni-Ca/ATP was firstly studied. • Effect of Ca content and preparation method on Ni/ATP structure was investigated. • Hydrothermal synthesis ( hs ) enhanced the distribution of Ca and Ni species over ATP. • Ni-6Ca/ATP- hs had strong CO 2 adsorption and abundant Ni-CaO x interfaces. • Ni-6Ca/ATP- hs exhibited superior performance and sinter/coke durability for GSR. Glycerol steam reforming (GSR) is one of the promising technologies that can realize renewable hydrogen production and efficient utilization of crude glycerol. To illuminate the functions of Ca content (3%, 6%, 9%, and 12%, by mass) and preparation method for Ni/ATP catalyst structure and its catalytic behaviors, the Ni- x Ca/ATP ( x = 3%, 6%, 9%, and 12%, by mass) catalysts are prepared by co-impregnation ( ci ) and hydrothermal synthesis ( hs ) method and then tested in GSR. Characterization results of XRD, N 2 adsorption–desorption, H 2 -TPR, HRTEM, XPS, and NH 3 /CO 2 -TPD demonstrate that the combined effect between appropriate Ca additive (6%, by mass) and hs enhance catalyst reducibility, uniform distribution of Ca additive and nickel species over ATP, and adsorption for CO 2 . This attributes to hs method protects the ATP framework through suppressing the interaction of Ca with ATP and promotes the formation of Ni-CaO x interface sites. Therefore, Ni-6Ca/ATP- hs exhibits the highest conversion (86.77%) of glycerol to gas product and H 2 yield (76.17%) and selectivity (58.56%) during GSR. Furthermore, XRD, HRTEM, TG-DTG and Raman analyses confirm that Ni-6Ca/ATP- hs also reveals outstanding anti-sintering and coke resistance. In addition, the structural evolution process of Ni/ATP catalyst with Ca introduction and hs method is presented. Considering the high performance, simple preparation process and low cost, the as-prepared catalyst providing new opportunities for utilization of glycerol derived from biodiesel industry.

Deformation Styles and Multi-Stage Evolution History of a Large Intraplate Strike-Slip Fault System in a Paleozoic Superimposed Basin: A Case Study From the Tarim Basin, NW China

The complex deformation styles of large intraplate strike-slip fault systems in the multi-stage superimposed basin are hot topics worldwide. This article proposes structural models and evolution processes for such strike-slip fault systems in the Tarim Basin based on high-resolution 3D seismic data and deep wells. Our analyses reveal that strike-slip fault in the Tarim Basin formed with different structural styles in five tectonic layers from the Sinian to the Permian that accompanies the Sinian rift systems and uplift, the Lower–Middle Cambrian reversed faults and salt tectonics, the Ordovician fault-karst systems, the Silurian to the Carboniferous en-echelon transtensional faults, and the Permian volcanic structures. Influenced by the multi-tectonic layers and complex evolution history, the strike-slip faults performed as multi-layer flower structures and various fault types. The evolution history of paleo-uplifts also influenced the distribution characteristics of strike-slip faults, such as X, diamond, and V shapes in the Tabei uplift and T shapes in the Tazhong uplift. The strike-slip faults formed in late Cambrian stage were associated with unconformities, inverted structures, and growth strata in deep layers. The different tectonic evolution models of the Tabei and the Tazhong uplift were built, which shows pre-existing structures, the lithological combinations from the rift basin to the marine basin, and the change of regional tectonic stress from the Cambrian to Permian are controlling factors of the strike-slip fault systems. These models provide a new interpretation method for intraplate strike-slip fault systems worldwide.

Dynamic evolution simulation of ablation zone in water-jet assisted laser machining of Korean pine (Pinus koraiensis)

In order to solve the difficulties with the observation of the ablation zone and the many factors that affect the dynamic evolution process of the ablation zone, the structural morphology and dynamic evolution process of the ablation zone in the process of water-jet assisted laser machining Korean pine (Pinus koraiensis) were studied. Based on the DFLUX subprogram, a compound heat source model was established. Under the comprehensive consideration of heat conduction, heat convection, heat radiation, and thermal physical properties varying with temperature, the three-dimensional (3D) finite element model of the Korean pine was numerically simulated by water-jet assisted laser machining. Through numerical simulation analysis, the cross-sectional morphology of Korean pine kerf was found to be screw-shaped, and the experimental results were in good agreement with the simulation results. The dynamic evolution law of water-jet assisted laser machining of Korean pine was obtained. In addition, as the laser power increased and the cutting speed decreased, the morphology of the Korean pine kerf remained unchanged, but the structure size of the Korean pine kerf showed an increasing change.

Consecutive hybrid mechanism boosting Na+ storage performance of dual-confined SnSe2 in N, Se-doping double-walled hollow carbon spheres

Rationally designed hierarchical structures and heteroatomic doping of carbon are effective strategies to enhance the stability and electrical conductivity of materials. Herein, SnSe2 flakes were generated in the double-walled hollow carbon spheres (DWHCSs), in which N and Se atoms were doped in the carbon walls, to construct SnSe2@N, Se-DWHCSs by confined growth and in-situ derivatization. The N and Se-doped DWHCSs can effectively limit the size increase of SnSe2, promote ion diffusion kinetics, and buffer volume expansion, which can be proved by electron microscope observation and density functional theory calculation. Consequently, the SnSe2@N, Se-DWHCSs as an anode material for sodium ion batteries (SIBs) demonstrated a distinguished reversible capacity of 322.8 mAh g−1 at 5 A g−1 after 1000 cycles and a superior rate ability of 235.3 mAh g−1 at an ultrahigh rate of 15 A g−1. Furthermore, the structure evolution and electrochemical reaction processes of SnSe2@N, Se-DWHCSs in SIBs were analyzed by ex-situ methods, which confirmed the consecutive hybrid mechanism and the phase transition process.

Phase-Field Model of Hydride Blister Growth Kinetics on Zirconium Surface

The precipitation of zirconium hydride blisters on the surface of zirconium alloy cladding destroys the integrity of the material and leads to material failure, which has serious potential safety hazards. To study the corrosion kinetics of zirconium hydride blisters, we established a phase-field model coupled with anisotropic elastic, which can reflect the microstructure evolution process of zirconium hydride blisters. The model studies the natural growth of hydride blister and the structural evolution process after applying radial stress and discusses the corrosion characteristics, stress distribution, and displacement changes. Zirconium hydride blisters tend to be semi-ellipsoidal in natural growth. Applying radial outward stress will promote the growth of blisters and aggravate the harm of corrosion. The stress state changes with applying stress, which affects the elastic driving force, resulting in the change of blister morphology. This work is helpful to understand the corrosion kinetic mechanism of hydride blisters.

Structural evolution and thermal runaway of refractory W and Mo nanotips in the vacuum under high electric field from PIC-ED-MD simulations

We performed multiscale-multiphysics simulations for W, Mo and Cu nanotips under high electric field to investigate their structural evolution and thermal runaway process. The critical electric field values for the electric prebreakdown condition are predicted to be 311 MV m−1, 570 MV m−1 and 675 MV m−1 for Cu, Mo and W nanotips respectively (R 0 = 1 nm, H 0 = 100 nm). The boiling point of the metal is found to be a good predictor of the critical electric field strength for the initiation of thermal runaway. For metal nanotips made of refractory metals such as W and Mo, the structural thermal runaway process is determined by the rapid growth of small protrusions and their subsequent sharpening and thinning under the high electric stress on the apex region. On the other hand, the more intense atomic evaporation of Cu metal nanotips is caused by the ejection of large droplets generated by recrystallization and necking of the molten region at the apex of the nanotip. The differences in the observed structural evolutions of nanotips between refractory metals and the Cu during the thermal runaway event clearly show the strong influence of melting and boiling points on the electric prebreakdown process in nanoscale.

Reversible anionic redox chemistry in layered Li4/7[□1/7Mn6/7]O2 enabled by stable Li–O-vacancy configuration

<h2>Summary</h2> The combination of anionic and cationic activities within Li-rich materials breaks through the traditional capacity limitation and achieves high-energy-density batteries. However, the utilization of anionic oxygen redox reactions always leads to detrimental lattice oxygen release, which accelerates structural distortion and electrochemical performance deterioration. In contrast to the typical Li–O–Li configuration in Li-rich layered oxides, not only can oxygen redox behaviors be triggered within layered Li_4/7[□_1/7Mn_6/7]O₂ (□: Mn vacancy) with Li–O-vacancy configuration, but lattice oxygen loss can be effectively suppressed. Upon Li⁺ (de)intercalations, Mn vacancy within the TM layer also enables reversible structural evolution and Li migration processes, further boosting high output capacity and long-term cycling stability. Besides, not only can the irreversible/reversible anionic/cationic redox reactions be clearly unraveled, but their capacity distributions can be roughly quantified upon cycling. Overall, our findings demonstrate that the introduction of Mn vacancy provides a promising configuration to achieve high-capacity cathode candidates for next-generation Li-ion batteries.

Interface engineering for boosting electrocatalytic performance of CoP-Co2P polymorphs for all-pH hydrogen evolution reaction and alkaline overall water splitting

Exploring cobalt phosphide catalysts with abundant active sites and outstanding intrinsic activity for active and robust hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) is highly desirable. Herein, by the fine-tuning thermal-reduction treatment of cobalt phosphonates with spherical shape, the novel carbon-wrapped CoP-Co2P polymorphs are rationally constructed. The unique hierarchical porous architecture and heterointerface of CoP-Co2P not only increase active sites but also ensure intrinsic activity. The resultant catalyst exhibits significantly boosted HER activity in a wide pH range, for instance, a current density of 10 mA cm−2 at the overpotential of 81 mV in 0.5 mol L−1 H2SO4, 109 mV in 1.0 mol L−1 KOH, and 227 mV in 1.0 mol L−1 phosphate buffer saline, and remarkable OER activity (1.53 V@10 mA cm−2 in 1.0 mol L−1 KOH), associated with the impressive stability for each reaction. Moreover, serving as the bifunctional electrocatalysts in a two-electrode electrolyzer for overall water splitting, a low cell voltage of 1.60 V can deliver a current density of 10 mA cm−2 in 1.0 mol L−1 KOH. The structural evolution process of the CoP-Co2P catalyst during electrolysis is thoroughly investigated. This work presents a new approach for designing and fabricating efficient and affordable metal phosphides for various electrochemical technologies.

Degrees of freedom for energy storage material

AbstractBuilding a bridge between properties and structures has always been the key focus of any materials research. Nowadays, energy storage materials, especially lithium‐ion batteries, are crucial both in daily life and for the research community. Therefore, there is an urgent need to discover the functionality origin of battery performances to improve and design better material systems. Functionality originates from local symmetry and field. Local symmetry can be described by four fundamental degrees of freedom: lattice, charge, orbital, and spin. On the basis of this, detailed descriptions of the battery's properties in terms of lattice, charge, orbital, and spin are presented from the perspective of frontier transmission electron microscopy in this review. Besides, frontier in situ methods are introduced to record the dynamic structural evolution process during the battery cycle. Future discussion from the perspectives of both materials and characterizations is provided at the end of this review.

Probing the Dynamic Structural Evolution of End-Functionalized Polybutadiene/Organo-Clay Nanocomposite Gels before and after Yielding by Nonlinear Rheology and 1H Double-Quantum NMR.

Understanding the structural evolution process after the yielding of networks in polymer nanocomposites can provide significant insights into the design and fabrication of high-performance nanocomposites. In this work, using hydroxyl-terminated 1,4-polybutadiene (HTPB)/organo-clay nanocomposite gel as a model, we explored the yielding and recovery process of a polymer network. Linear rheology results revealed the formation of a nanocomposite gel with a house-of-cards structure due to the fully exfoliated 6 to 8 wt% organo-clays. Within this range, nonlinear rheologic experiments were introduced to yield the gel network, and the corresponding recovery processes were monitored. It was found that the main driving force of network reconstruction was the polymer–clay interaction, and the rotation of clay sheets played an important role in arousing stress overshoots. By proton double-quantum (1H DQ) NMR spectroscopy, residual dipolar coupling and its distribution contributed by HTPB segments anchored on clay sheets were extracted to unveil the physical network information. During the yielding process of a house-of-cards network, e.g., 8 wt% organo-clay, nearly one-fourth of physical cross-linking was broken. Based on the rheology and 1H DQ NMR results, a tentative model was proposed to illustrate the yielding and recovery of the network in HTPB/organo-clay nanocomposite gel.

Insights into the enhanced Lithium-Ion storage performance of CoSx/Carbon polyhedron hybrid anode

In this work, the 3D cobalt sulfide/carbon polyhedral (CoSx/CP) hybrids (x = 1, 2) have been fancily prepared by employing the ZIF-67 as template. The as-prepared CoSx/CP inherit the structure of ZIF-67, realizing the polyhedral structure where the CoSx nanoparticles are well embedded. The battery performance measurements demonstrate that the CoS2 has played a significant role contributing to the lithium ions batteries (LIBs) performance of CoSx/CP. As a result, the capacity of the optimized CoSx/CP is 562 mAh g−1 after 300 cycles at 0.5 A g−1. When cycled at 10 A g−1, it delivers a reversible specific capacity of 131 mAh g−1. The electrochemical analysis points out that the optimized CoSx/CP possesses diverse electrochemical reactions and the lowest charge transfer resistance. Moreover, the insertion mechanism and structural evolution process of CoSx/CP are examined by the in-situ XRD. Beyond that, the unique nanoarchitecture of CoSx/CP guarantees the high specific surface area which enables the large electrode–electrolyte contract area, fast ions diffusion/electron transfer and robust structural stability. Meanwhile, the carbon skeleton is deductive to confine the huge volume expansion of CoSx as well.

Temperature effects on water retention behaviour and structural evolution of GMZ bentonite pellet mixtures

Mixtures of high-density, multi-sized bentonite pellets are considered as a promising buffer/backfill material for deep geological disposal of high-level radioactive waste (HLW). During the operation of a HLW repository, the pellet mixtures will be subjected to ground water infiltrated from surrounding rock and elevated temperatures induced by nuclide decay heat, leading to a complex hydro-mechanical behaviour. In this paper, water retention tests with suction controlled by vapour equilibrium and osmotic techniques, as well as structural observations by mercury intrusion porosimetry (MIP) were performed on three kinds of specimens of Gaomiaozi (GMZ) bentonite at different temperatures (20, 40, 60 and 80 °C), including constant-volume pellet mixtures (PM) and compacted blocks (CB) with an identical dry density (1.45 Mg/m3) and free-swelling single pellets with the same initial dry density (1.95 Mg/m3) as those involved in the PM specimen. For the three kinds of specimens, the water retention capacity decreased with increasing temperature. From a perspective of thermal dynamics theory, it is concluded that in high suction range (> 10 MPa), increasing temperature inhibited the water adsorption and promoted the water desorption process consequently leading to a decreasing water retention capacity. According to the capillary law (Young – Laplace equation), in the low suction range (< 10 MPa), increasing temperature reduces the capillary water content in terms of decreasing the surface tension, contact angle and density of the capillary water, as well as expanding the entrapped pore air. Meanwhile, the MIP test results illustrate that during hydration, most of the large pores (2000–360,000 nm) were gradually converted into medium pores (100–2000 nm) while the change of small pores (6.4–100 nm) and inaccessible pores (< 6.4 nm and > 360,000 nm) were limited. Compared to the effect of suction, the temperature influence on this structural evolution process was relatively slight. Therefore, the temperature-dependent water retention behaviour was mainly caused by temperature-induced changes of water-clay interactions as well as physical properties of adsorbed and capillary water during hydration, rather than the limited changes of pore structure of the specimen.

Pore evolution of microporous magnesia aggregates with the introduction of nano-sized MgO

Microporous refractories applied in the working-lining of metallurgical furnaces have been rapidly developed in recent years owing to the outstanding mechanical properties, thermal insulation performance and slag resistance, the pore structure of which plays a critical role in the variation of service performance. Meanwhile, the microporous magnesia aggregates were prepared in our previous research with the introduction of nano-sized particles to overcome the shortcomings of high thermal conductivity, poor thermal shock resistance and slag penetration resistance, however, the pore evolution during sintering still remains to be investigated. Hence, in this study, the pore evolution of microporous magnesia aggregates is explored specifically and the effect of nano-sized MgO on pore structure and sintering is simultaneously discussed. The sintering model of microporous magnesia was built for analyzing the pore structure evolution process. The results revealed that a micro-nano double-scale sintering model developed by the introduction of nano-sized MgO dramatically promoted the sintering kinetic force and boundary migration velocity. The sintering pressure discrepancy and free energy change per unit mole of specimens were respectively increased by ∼43 times and ∼48 times, which effectively improved the closed porosity and pore distribution homogeneity, while reduced the pore size. Meanwhile, the high sintering diving force lead to the significant improvement of direct bonding degree and grain size of microporous magnesia. With the addition of 3 wt% nano-sized MgO, the optimal sintering properties with closed porosity of 6.4%, bulk density of 3.23 g/cm3 and median equivalent pores diameters of 4.07 μm were achieved. The exploration of pore evolution in microporous magnesia aggregates contributed to the fabrication and industrialization development of microporous refractories.

From structure evolution of palygorskite to functional material: A review

Palygorskite (PAL) is a modulated rod-like phyllosilicate with abundant reserves in nature, which has the characteristics of a 2:1 layered-chain crystal structure, one-dimensional nanorod crystal morphology, regularly arranged tunnels/channels, and rich surface active sites. In the long-term research process, various modification strategies have been conducted to adjust the order of the structure, regulate the pore structure, change the stacking pattern, and further optimize the morphological characteristics and surface properties of PAL to improve its application performance and expand its application range. Currently, it has been possible to manipulate the basic tetrahedron-octahedron of PAL and even self-assemble available components to promote the rearrangement or reconstruction of the PAL structure to transform into new mineral functional materials. Structural evolution provides a new approach for better application of PAL in wider fields. This article comprehensively reviews the different ways to induce the structural evolution of PAL to fabricate functional materials and emphasizes the sustainable development paths for the transformation and utilization of low-grade PAL clay with a variety of complex associated minerals. It is expected that the summary of the structural evolution process of PAL can help to understand the structure at a deeper level and develop novel functional materials in a wider dimension, ultimately facilitating the value-added, comprehensive, and ecological development of PAL clay resources. • Recent progress of PAL structure evolution to functional materials is reviewed. • Process and mechanism of PAL structure evolution is discussed. • Transformation and utilization paths of low-grade PAL clay are emphasized. • Several suggestions are proposed for the development of PAL resource.

Correlating the initial gas evolution and structural changes to cycling performance of Co-free Li-rich layered oxide cathode

Alternatives to Lithium-rich layered oxides xLi2MnO3∙(1−x)LiNi1−y−zCoyMnzO2 (LR-NCMs) are needed, despite them being promising high-capacity cathode materials for next generation of high-energy batteries, because these materials contain toxic Co in their structure and their practical applications are restricted by prominent capacity and voltage fade, caused by structural transformation upon long-term cycling. To address these issues, a search for a low-cost, Co-free Li-rich cathode materials with a better surface structural stability than LR-NCMs is ongoing. One of such compounds is Li1.16Ni0.19Fe0.18Mn0.46O2 (LNFM). Our as-synthesized LNFM cathode not only delivers a high specific capacity of 229 mAh g−1 with the capacity retention of 83% in half-cell and 81% in a full-cells but also a stable average discharge voltage, even when cycled at C/5 rate to upper cutoff potential of 4.8 V vs Li+/Li in additive-free electrolyte. Both operando and post mortem characterization was used to understand the structural changes, gas evolution and oxygen redox processes of LNFM material, as well as to understand cathode−electrolyte interfacial reactions and their correlation to the improved electrochemical performance. The gained understanding will help designing new high-capacity Co-free cathode materials, meeting the performance requirements for future high-energy density batteries.

Tuning core-shell structural architecture for high-performance Li-Mn-O layered oxides

Being free of cobalt and nickel, Li-Mn-O layered oxides are considered as one of the most promising candidate cathodes due to the low cost and high specific capacity. The relatively poor thermal stability of Li-Mn-O layered oxides can lead to battery safety issues, and thus needs to be improved for practical applications. Herein, we systemically investigated the heat-induced structural/chemical evolution of a Li-Mn-O material, revealing a two-step phase transition process through concurrent Li and O loss, heterogeneously occurring in the bulk and at the surface of the primary particles. Based on the understanding of structural change, two new Li-Mn-O materials with different core-shell microstructures, one with a spinel shell and another with an orthorhombic shell, were synthesized. Experimentally, the one with the spinel shell achieved an ultrahigh decomposition temperature of ~300 °C, which is vital for battery safety. This material also exhibited greatly enhanced cycling stability and rate capability due to the protection role of the spinel shell. This work paves new routes to produce high-performance cathode materials with various heterostructure architectures through the tunning temperature-sensitive structure evolution process.

Scenario Expression Method for Regional Geological Structures

Knowing the GIS expression of geological phenomena is an important basis for the combination of geology and GIS. Regional geological structures include folds, faults, strata, rocks, and other typical geological phenomena and are the focus of geological GIS research. However, existing research on the GIS expression of regional geological structure focuses on the expression of the spatial and attribute characteristics of geological structures, and our knowledge of the expression of the semantic, relationship, and evolution processes of geological structures is not comprehensive. In this paper, a regional geological structure scene expression model with the semantic terms positional accuracy, geometric shape, relationship type, attribute type, and time-type attributes and operations is proposed. A regional geological structure scenario markup language (RGSSML) and a method for mapping it with graphics are designed to store and graphically express regional geological structure information. According to the geological time scale, a temporal reference coordinate system is defined to dynamically express the evolution of regional geological structures. Based on the dynamic division of the time dimension of regional geological structures, the expression method of “time dimension + space structure” for the regional geological structure evolution process is designed based on the temporal model. Finally, the feasibility and effectiveness of the regional geological structure scene expression method proposed in this paper is verified using the Ningzhen Mountain (Nanjing section) as an example. The research results show that the regional geological structure scene expression method designed in this paper has the following characteristics: (1) It can comprehensively express the spatial characteristics, attribute characteristics, semantics, relationships, and evolution processes of regional geological structures; (2) it can be used to realize formalized expression and unified storage of regional geological information; and (3) it can be used to realize dynamic expression of the regional geological structure evolution process. Moreover, it has significant advantages for the expression of regional geological structure semantics, relationships, and evolution processes. This study improves our knowledge of the GIS expression of regional geological structures and is expected to further promote the combination and development of geology and GIS.

Improving performance of zinc-manganese battery via efficient deposition/dissolution chemistry

Aqueous zinc-manganese batteries with rapid development are faced with many issues, such as insufficient capacity and low energy density. Here, the efficient dissolution/deposition chemistry interfered by anionic groups of electrolyte was proposed, which achieves a dramatic improvement of the specific capacity at low current density in Zn-MnO2 system. It was demonstrated that the reaction mechanism is dissolution-deposition mechanism coupled with Zn2+/H+-insertion/extraction. Meanwhile, the capacity provided by dissolution/deposition process was evaluated by semi-quantitative. These findings also open up new horizons for artificially manipulating the structural evolution and electrochemical process of Mn-based cathodes, and pave a way in designing advanced zinc-manganese batteries.

Operando Monitoring and Deciphering the Structural Evolution in Oxygen Evolution Electrocatalysis

AbstractThe oxygen evolution reaction (OER) acts as the bottleneck of some crucial energy conversion and storage technologies involving water electrolysis, CO2 electrolysis, and metal‐air batteries, among others. The challenging sluggish reaction kinetics of the OER can be overcome via developing highly efficient electrocatalysts, which experience a dynamic structural evolution process during the reaction. However, the reaction mechanism of the structural transformation of electrocatalysts during the OER and the structure‐activity correlation in understanding the real active sites remain elusive. Fortunately, operando characterizations offer a platform to study the structural evolution processes and the reaction mechanisms of OER electrocatalysts. In this review, using several in situ/operando techniques some recent advances are elaborated with emphases on tracking the structural evolution processes of electrocatalysts, recording the reaction intermediates during electrocatalysis, and building a link between the structure and activity/stability of electrocatalysts. Moreover, theoretical considerations are also discussed to assist operando characterization understanding. Finally, some perspectives are provided which are expected to be helpful to tackle the current challenges in operando monitoring and unraveling the reaction mechanisms of OER electrocatalysts.