The stability of high-energy-density lithium metal batteries depends on the uniformity of solid electrolyte interphase (SEI) on lithium metal anodes. Rationally improving SEI uniformity is hindered ...by poorly understanding the effect of structure and components of SEI on its uniformity. Herein, a bilayer structure of SEI formed by isosorbide dinitrate (ISDN) additives in localized high-concentration electrolytes was demonstrated to improve SEI uniformity. In the bilayer SEI, LiN
O
generated by ISDN occupies top layer and LiF dominates bottom layer next to anode. The uniformity of lithium deposition is remarkably improved with the bilayer SEI, mitigating the consumption rate of active lithium and electrolytes. The cycle life of lithium metal batteries with bilayer SEI is three times as that with common anion-derived SEI under practical conditions. A prototype lithium metal pouch cell of 430 Wh kg
undergoes 173 cycles. This work demonstrates the effect of a reasonable structure of SEI on reforming SEI uniformity.
Through the use of video technology, satellites can detect dynamic targets and analyze their motion characteristics. Target tracking can extract dynamic information about key ground targets for ...target monitoring and trajectory prediction by satellite video. Tracking algorithms are affected by target motion characteristics, such as velocity and direction, as well as background characteristics, such as illumination changes, occlusion, and background similarities with the target. However, these problems are seldom studied with satellite video cameras. Current algorithms are unsuitable for satellite video because of the poor texture and color features of the target in satellite video. Therefore, in this article, we enhance target tracking for satellite video technology using two aspects: 1) sample training strategy and 2) sample characterization. We establish a filter training mechanism for the target and background to improve the discrimination ability of the tracking algorithm. We then build a target feature model using a Gabor filter to enhance the contrast between the target and background. Moreover, we propose a tracking state evaluation index to avoid tracking drift. Tracking experiments using nine sets of Jilin-1 satellite videos show that the proposed approach can accurately locate a target under weak feature attributes. Therefore, this article contributes to more robust tracking using satellite video technology.
Oily water caused in the process of industry leads to not only the waste of resources, but also environmental pollution. Membrane separation, as a facile and efficient separation technology, has ...attracted widespread attention in the field of oil/water separation. The development of membrane materials with high separation performance is one of the key elements to improve separation efficiency. In this work, a superhydrophobic membrane composited with a trifluoromethyl‐containing covalent organic framework (COF) is prepared, which exhibits excellent performance on separations of oil/water mixtures and water‐in‐oil emulsions. For different composition of oil/water mixtures, the highest flux of oil is up to 32 000 L m−2 h−1 and oil/water separation efficiency is above 99%. Moreover, the high oil/water separation efficiency remains unchanged after successive cycles. This work provides a feasible scheme for the design of high‐efficiency oil/water separation membranes.
A superhydrophobic membrane composited with a trifluoromethyl‐containing COF is prepared. The membrane exhibits excellent performance on separations of oil/water mixtures and water‐in‐oil emulsions. For different composition of oil/water mixtures, the highest flux of oil is up to 32 000 L m−2 h−1 and oil/water separation efficiency is above 99%. Moreover, the high oil/water separation efficiency remains unchanged after successive cycles.
Lithium metal is used to achieve high‐energy‐density batteries due to its large theoretical capacity and low negative electrochemical potential. The introduction of quasi‐solid electrolytes ...simultaneously overcomes the safety problems induced by the liquid electrolytes and the high interfacial resistance issues confronted by all solid‐state electrolytes. In‐depth investigations involving interfacial behaviors in quasi‐solid lithium metal batteries are inadequate. Herein an ultrathin Li3OCl quasi‐solid‐state electrolyte layer (500 nm thickness) is used to cover a lithium anode. The polarization of the anode is remarkably reduced by introducing the Li3OCl quasi‐solid‐state electrolyte. In contrast to the decomposition of solvents in a standard electrolyte (EC‐DEC,1.0 m LiPF6), the established quasi‐solid‐state electrolyte interfaces can significantly inhibit the decomposition of solvents when the cut‐off voltage is 4.5 V.
The interfacial behavior of the quasi‐solid‐state electrolyte layer Li3OCl was investigated with a three‐electrode setup. An ultrathin Li3OCl layer can remarkably reduce the over‐potential of the lithium anode and inhibit solvent decomposition, significantly prolonging the service life of a high‐voltage (4.5 V) lithium metal battery.
The demand for highly efficient conversion and storage of renewable energy sources calls for advanced electrocatalytic technologies. 2D graphene has long been investigated as a versatile material ...platform with flexible structure and tunable surface properties for the design of efficient electrocatalysts. In recent years, new types of graphene derivatives and analogues keep emerging and showing great potential for highly active and selective electrocatalytic applications. In this review, recent progresses on emerging graphene derivatives and analogues for electrocatalysis are summarized. This review starts from the introduction of the material requirements for efficient electrocatalysis and the advantages of 2D graphene derivatives and analogues. Then new advances on graphene derivatives for electrocatalysis are introduced, including twisted graphene superlattices, molecular‐level single‐atom catalysts, and graphene‐supported dual‐atom catalysts or atomic clusters. The next section deals with the emerging research directions of graphene analogues for electrocatalysis, including 2D metal‐free materials, metallenes, 2D transition metal borides (MBenes), and new design strategies of them. Finally, an overview on the development status of this field is provided, and perspectives on the future development of efficient electrocatalytic technologies based on 2D materials are proposed.
Graphene derivatives including twisted graphene superlattices, molecular‐level single‐atom catalysts and graphene‐supported dual‐atom catalysts, as well as graphene analogues including metal‐free materials, metallenes, and transition metal borides are reviewed with an emphasis on the structure–performance relationship of 2D electrocatalysts.
We demonstrate a novel preparative strategy for the well-controlled MnCo2O4.5@MnO2 hierarchical nanostructures. Both δ-MnO2 nanosheets and α-MnO2 nanorods can uniformly decorate the surface of ...MnCo2O4.5 nanowires to form core–shell heterostructures. Detailed electrochemical characterization reveals that MnCo2O4.5@δ-MnO2 pattern exhibits not only high specific capacitance of 357.5 F g−1 at a scan rate of 0.5 A g−1, but also good cycle stability (97% capacitance retention after 1000 cycles at a scan rate of 5 A g−1), which make it have a promising application as a supercapacitor electrode material.
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•Manganese cobalt oxide@manganese dioxides hierarchical nanostructures.•Morphology and crystallinity-controlled synthesis.•High specific capacitance of MnCo2O4.5@δ-MnO2: 357.5 F g−1 at current density of 0.5 A g−1.•Good cycle stability: 97% capacitance retention after 1000 cycles at a scan rate of 5 A g−1.
•Geometrical interpretation of analysis-oriented models for FRP-confined concrete.•Methodology for calibrating analysis-oriented models.•Justification of design-oriented models.
An important ...application of fibre-reinforced polymer (FRP) composites in structural engineering is to confine concrete. In contrast to actively confined concrete, the stress-strain curve of FRP-confined concrete can have a second ascending branch when sufficient confinement is applied. Numerous analytical models have been proposed to predict the axial stress–strain behaviour of FRP-confined concrete. These models can be classified into two categories: (a) analysis-oriented models and (b) design-oriented models. In this paper, a 3-dimensional geometrical approach is proposed to interpret the general theory of analysis-oriented models based on three general equations. This approach provides an intuitive perspective to understand the analysis-oriented models and the mechanism of FRP-confined concrete. With this approach, a systematic methodology for calibrating analysis-oriented models is demonstrated, and the parameters in design-oriented models are justified. This methodology can also be applied to build analysis-oriented models for other concrete-type materials.
Lithium–sulfur (Li–S) battery system is endowed with tremendous energy density, resulting from the complex sulfur electrochemistry involving multielectron redox reactions and phase transformations. ...Originated from the slow redox kinetics of polysulfide intermediates, the flood of polysulfides in the batteries during cycling induced low sulfur utilization, severe polarization, low energy efficiency, deteriorated polysulfide shuttle, and short cycling life. Herein, sulfiphilic cobalt disulfide (CoS2) was incorporated into carbon/sulfur cathodes, introducing strong interaction between lithium polysulfides and CoS2 under working conditions. The interfaces between CoS2 and electrolyte served as strong adsorption and activation sites for polar polysulfides and therefore accelerated redox reactions of polysulfides. The high polysulfide reactivity not only guaranteed effective polarization mitigation and promoted energy efficiency by 10% but also promised high discharge capacity and stable cycling performance during 2000 cycles. A slow capacity decay rate of 0.034%/cycle at 2.0 C and a high initial capacity of 1368 mAh g–1 at 0.5 C were achieved. Since the propelling redox reaction is not limited to Li–S system, we foresee the reported strategy herein can be applied in other high-power devices through the systems with controllable redox reactions.
•The AdaBoost algorithm is adopted to predict the compressive strength of concrete.•1030 sets of data is collected to train the model and reaches an accuracy of 98%.•Different algorithms are compared ...to show the superior of the proposed model.•Key factors and in the AdaBoost and influence of input variables are investigated.
In this paper, an intelligent approach based on the machine learning technique is proposed for predicting the compressive strength of concrete. This approach employs the adaptive boosting algorithm to construct a strong learner by integrating several weak learners, which can find the mapping between the input data and output data. The weak learner whose predicting error is small will have a larger weight in the entire system, thus the overall accuracy of the strong learner will be enhanced. A total of 1030 sets of concrete compressive strength tests is collected to train and test the learners, in which the concrete mixture components (e.g., coarse/fine aggregates, cement, water, additive, etc.) and the curing time are set as the input data while the compressive strength value is set as the output data. The proposed approach is validated through a 10-fold cross validation method, and reaches an average accuracy of over 95% in sense of determination coefficient. In addition, a new dataset of 103 samples for concrete compressive strength is also adopted to demonstrate the generalization power of the proposed mode. The proposed approach is also compared to some other individual machine learning techniques that are already applied in this field, e.g., artificial neural network (ANN) and support vector machine (SVM), and shows superior advantages over these methods. Finally, the influence of some key factors in the adaptive boosting approach is also investigated, e.g., the amount of training data, the choice of weak learner, and the influence of the sensitivity and number of the input parameters. It is shown that using 80% of the total data for training can obtain acceptable prediction results and decision tree is the best choice for the weak learner in the boosting framework. Also, the importances of different input variables are obtained based on the sensitivity analysis results.
Electrochemical energy storage systems play an increasingly important role in our daily lives. The detection/estimation of the state of electrochemical cells is therefore a prerequisite for the ...development of safe, high‐performance batteries. Reference electrodes (REs) are an effective tool for monitoring the status of batteries and are of critical significance in this field. However, the practical construction of a durable RE for long‐term research and industrial applications is still challenging. In this article, the fundamental principles of a three‐electrode system featuring the presence of REs are elucidated. The design parameters of REs in lithium batteries, including active materials, manufacturing, geometry, and placement, are comprehensively summarized, and the typical applications of REs in practical lithium‐ion batteries to facilitate working/failure mechanism analysis and methods to monitor Li plating are analyzed. Finally, the challenges and future trends of the exploitation and deployment of REs in lithium batteries are presented.
This article outlines the design and usage specifications of reference electrodes for lithium batteries, from the fundamental principles to the corresponding application examples in batteries, and offers great value to the community, increasing our knowledge of the coupled information in batteries.
