To pursue a higher energy density (>300 Wh kg−1 at the cell level) and a lower cost (<$125 kWh−1 expected at 2022) of Li‐ion batteries for making electric vehicles (EVs) long range and ...cost‐competitive with internal combustion engine vehicles, developing Ni‐rich/Co‐poor layered cathode (LiNi1−x−yCoxMnyO2, x+y ≤ 0.2) is currently one of the most promising strategies because high Ni content is beneficial to high capacity (>200 mAh g−1) while low Co content is favorable to minimize battery cost. Unfortunately, Ni‐rich cathodes suffer from limited structure stability and electrode/electrolyte interface stability in the charged state, leading to electrode degradation and poor cycling performance. To address these problems, various strategies have been employed such as doping, structural optimization design (e.g., core–shell structure, concentration‐gradient structure, etc.), and surface coating. In this review, five key aspects of Ni‐rich/Co‐poor layered cathode materials are explored: energy density, fast charge capability, service life including cycling life and calendar life, cost and element resources, and safety. This enables a comprehensive analysis of current research advances and challenges from the perspective of both academy and industry to help facilitate practical applications for EVs in the future.
Current research advances and challenges in the field of Ni‐rich NCM cathodes for electric vehicles both in academy and industry, along with future perspectives are discussed. Ni‐rich NCM cathodes for automotive applications in five key aspects including energy density, fast charge capability, service life, cost and element resources, and safety are analyzed comprehensively.
Nonintrusive load monitoring refers to inferring what appliances are operating in a household at a given time solely from fluctuations on the main power feeder. It is one approach to demand-side ...management strategies in the smart grid, and most current research employs machine learning to make those inferences. However, the learning algorithms used usually require knowledge of the set of appliances active at each sample instant in addition to the main feeder fluctuations. This data is not ordinarily available in field usage. As a compromise, we examine semi-supervised learning algorithms, which only need a small sample of observed power signals annotated with active appliances (e.g., from an initial "registration" period). As multiple independent appliances may operate concurrently, we furthermore employ multilabel classification in our solution. Three new graph-based semi-supervised multilabel load monitoring algorithms are proposed and evaluated on five public datasets. We find that the best algorithm can outperform state-of-the-art results on these datasets.
The government and the market are the two main means for resource allocation, and both play important roles in economic development and environmental protection. Based on the theoretical mechanism ...analysis, this study empirically investigated the relationship between government intervention, market development, and China's provincial pollution emission efficiency by using the static panel OLS, system generalized method of moments (SYS-GMM), and panel threshold effect model during the period 2000–2017. The results show that the impact of government intervention on China's provincial pollution emission efficiency shows a non-linear U-shaped curve relationship, and there is a positive correlation between market development and provincial pollution emission efficiency in China. Government intervention and market development are complementary, rather than a substitute for each other, in promoting China's provincial pollution emission efficiency. When government intervention is set as the threshold variable, the impact of government intervention on China's provincial pollution emission efficiency shows the feature of “promotes first, then inhibits.” However, when market development is set as the threshold variable, government intervention is only conducive to the improvement of China's provincial pollution emission efficiency at a moderate marketization level. Lastly, some policy implications related to the government and the market in enhancing China's provincial pollution emission efficiency are presented.
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•The relationship between government intervention, market development and pollution emission efficiency is investigated from both theoretical and empirical perspectives.•Government intervention and market development are complementary in promoting China’s provincial pollution emission efficiency.•Panel threshold effect model is employed to explore the joint impact of government intervention, market development on China’s provincial pollution emission efficiency.
Molecular sieving membranes with sufficient and uniform nanochannels that break the permeability-selectivity trade-off are desirable for energy-efficient gas separation, and the arising ...two-dimensional (2D) materials provide new routes for membrane development. However, for 2D lamellar membranes, disordered interlayer nanochannels for mass transport are usually formed between randomly stacked neighboring nanosheets, which is obstructive for highly efficient separation. Therefore, manufacturing lamellar membranes with highly ordered nanochannel structures for fast and precise molecular sieving is still challenging. Here, we report on lamellar stacked MXene membranes with aligned and regular subnanometer channels, taking advantage of the abundant surface-terminating groups on the MXene nanosheets, which exhibit excellent gas separation performance with H
permeability >2200 Barrer and H
/CO
selectivity >160, superior to the state-of-the-art membranes. The results of molecular dynamics simulations quantitatively support the experiments, confirming the subnanometer interlayer spacing between the neighboring MXene nanosheets as molecular sieving channels for gas separation.
Constructing 3D carbon structures built from carbon nanotubes (CNTs) and graphene has been considered as an effective approach to achieve superior properties in energy conversion and storage because ...of the synergistic combination of the advantages of each building block. Herein, a facile solid‐state growth strategy is reported for the first time to fabricate highly nitrogen doped CNT–graphene 3D nanostructures without the necessity to use chemical vapor deposition. As cathode hosts for lithium–sulfur batteries, the hybrid architectures exhibit reversible capacities of 1314 and 922 mAh g−1 at 0.2 and 1 C, respectively, and a capacity retention of 97% after 200 cycles at a high rate of 2 C, revealing their great potential for energy storage application.
Using a facile and green solid‐state growth strategy, 3D, well‐interconnected, highly nitrogen‐doped carbon nanotube–graphene hybrid structures are designed and fabricated by using Ni foam as growth substrate and catalyst, glucose as carbon sources, and dicyandiamide as nitrogen sources. When used as cathode hosts for Li–S batteries, the obtained product shows superior lithium‐storage capability.
The recent discoveries of transition‐metal dichalcogenides (TMDs) as novel 2D electronic materials hold great promise to a rich variety of artificial van der Waals (vdWs) heterojunctions and ...superlattices. Moreover, most of the monolayer TMDs become intrinsically piezoelectric due to the lack of structural centrosymmetry, which offers them a new degree of freedom to interact with external mechanical stimuli. Here, fabrication of flexible vdWs p–n diode by vertically stacking monolayer n‐MoS2 and a few‐layer p‐WSe2 is achieved. Electrical measurement of the junction reveals excellent current rectification behavior with an ideality factor of 1.68 and photovoltaic response is realized. Performance modulation of the photodiode via piezo‐phototronic effect is also demonstrated. The optimized photoresponsivity increases by 86% when introducing a −0.62% compressive strain along MoS2 armchair direction, which originates from realigned energy‐band profile at MoS2/WSe2 interface under strain‐induced piezoelectric polarization charges. This new coupling mode among piezoelectricity, semiconducting, and optical properties in 2D materials provides a new route to strain‐tunable vdWs heterojunctions and may enable the development of novel ultrathin optoelectronics.
Tunability over the MoS2/WSe2 vdWs interface property is achieved through mechanical strain. The strain‐induced energy band tilting promotes separation and extraction of photoexcited carriers across interface and enhances the photodiode performance dramatically. This study provides a new route to a tunable van der Waals interface rather than by electrostatic gating, which may enable the development of novel flexible optoelectronics.
Three six‐coordinate DyIII single‐molecule magnets (SMMs) Dy(OtBu)2(L)4+ with local D4h symmetry are obtained by optimizing the equatorial ligands. One of the compounds with L=4‐phenylpyridine shows ...an energy barrier (Ueff) of 2075(11) K, which is the third largest Ueff, and the first Ueff>2000 K for SMMs with axial‐type symmetry so far. Ab initio analysis indicates that the exceptional uniaxial magnetic anisotropy is deeply related to the axially compressed octahedral geometry. This work provides a new insight into the local D4h symmetry for high‐performance SMMs.
Building single‐molecule magnets: A compressed octahedral dysprosium(III) single‐molecule magnet with local D4h symmetry exhibits an energy barrier over 2000 K.
Plant-pathogen interactions induce a signal transmission series that stimulates the plant's host defense system against pathogens and this, in turn, leads to disease resistance responses. Plant ...innate immunity mainly includes two lines of the defense system, called pathogen-associated molecular pattern-triggered immunity (PTI) and effector-triggered immunity (ETI). There is extensive signal exchange and recognition in the process of triggering the plant immune signaling network. Plant messenger signaling molecules, such as calcium ions, reactive oxygen species, and nitric oxide, and plant hormone signaling molecules, such as salicylic acid, jasmonic acid, and ethylene, play key roles in inducing plant defense responses. In addition, heterotrimeric G proteins, the mitogen-activated protein kinase cascade, and non-coding RNAs (ncRNAs) play important roles in regulating disease resistance and the defense signal transduction network. This paper summarizes the status and progress in plant disease resistance and disease resistance signal transduction pathway research in recent years; discusses the complexities of, and interactions among, defense signal pathways; and forecasts future research prospects to provide new ideas for the prevention and control of plant diseases.
Improving the green total-factor productivity (GTFP) is a key measure to coordinate industrial development and environmental protection in China. This study adopts the biennial Malmquist–Luenberger ...(BML) productivity index to estimate the GTFP change of China's 34 industrial subsectors covering the period 2005–2015. Subsequently, fixed-effect panel quantile regression is applied to analyze the heterogeneous effects of eight selected influencing factors on China's industrial GTFP change. The results show that China's overall industrial GTFP exhibited an increasing trend during the study period and varied greatly in different sub-sectors. Moreover, technological innovation rather than efficiency promotion was the main contributor to the improvement of industrial GTFP in China. The impact of the scale structure (SS) was significantly positive across the quantiles and maintained a slightly downward trend. The impact of the property rights structure (PTS) was significantly negative and showed an increasing trend across the quantiles. The impact of the energy intensity (EI) slightly increased and was significantly negative at most quantiles. The energy consumption structure (ECS) exhibited an increasing trend and had a significantly negative effect at the middle quantiles. Technological innovation (TI) exerted a significantly positive effect and displayed a downward trend across the quantiles, and it was the most important factor to drive industrial GTFP growth. The “pollution halo” hypothesis and the Porter hypothesis were both verified with a certain range from the analysis of foreign direct investment (FDI) and environmental regulation (ER), as well as the interaction between ER and TI. Our results stress the importance of the heterogeneous effects of these influencing factors on different quantile subsectors when formulating the related measures and policies.
The above figure intuitively illustrates the relationship between the eight influencing factors and industrial green total factor productivity change in China according to the estimation results of the fixed-effect panel quantile regression approach, which visually shows the heterogeneous effects of all influencing factors on China's industrial green total factor productivity. Display omitted
•The biennial Malmquist-Luenberger (BML) index is used to estimate China’s industrial GTFP growth.•The panel quantile regression is employed to investigate the influencing factors of China’s industrial GTFP growth.•Technological progress rather than efficiency promotion is the main contributor to China’s industrial GTFP growth.•The effects of all influencing factors on China’s industrial GTP growth are heterogeneous at different quantiles.
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