Driving range and fast charge capability of electric vehicles are heavily dependent on the 3D microstructure of lithium-ion batteries (LiBs) and substantial fundamental research is required to ...optimise electrode design for specific operating conditions. Here we have developed a full microstructure-resolved 3D model using a novel X-ray nano-computed tomography (CT) dual-scan superimposition technique that captures features of the carbon-binder domain. This elucidates how LiB performance is markedly affected by microstructural heterogeneities, particularly under high rate conditions. The elongated shape and wide size distribution of the active particles not only affect the lithium-ion transport but also lead to a heterogeneous current distribution and non-uniform lithiation between particles and along the through-thickness direction. Building on these insights, we propose and compare potential graded-microstructure designs for next-generation battery electrodes. To guide manufacturing of electrode architectures, in-situ X-ray CT is shown to reliably reveal the porosity and tortuosity changes with incremental calendering steps.
Although online consumer reviews (OCRs) have helped consumers to know about the strengths and weaknesses of different products and find the ones that best suit their needs, they introduce a challenge ...for businesses to analyze them because of their volume, variety, velocity and veracity. This research investigates the predictors of readership and helpfulness of OCR using a sentiment mining approach for big data analytics. Our findings show that reviews with higher levels of positive sentiment in the title receive more readerships. Sentimental reviews with neutral polarity in the text are also perceived to be more helpful. The length and longevity of a review positively influence both its readership and helpfulness. Because the current methods used for sorting OCR may bias both their readership and helpfulness, the approach used in this study can be adopted by online vendors to develop scalable automated systems for sorting and classification of big OCR data which will benefit both vendors and consumers.
•Investigating the effect of review sentiment on readership and helpfulness of OCR.•Providing a research model that predicts the performance of OCR.•Reviews with higher levels of positive sentiment in the title receive more readerships.•Reviews with neutral polarity in the text are perceived to be more helpful.•Length and longevity of a review positively influence both its readership and helpfulness.
Palladium-based alloy materials as cathodes for the reduction of oxygen are regarded as potential substitutes for platinum-based catalysts in fuel cells. In this work, we present a scientometric ...analysis and critically review the use of Pd alloys for the oxygen reduction reaction (ORR). Through scientometric analysis, publication information, research fronts and hotspots are identified. For the critical review, reaction mechanisms in different media are discussed, with the aid of volcano plots to show the general principles for catalyst modifications to maximise the ORR. Influencing factors, including alloying, structure, strain and ligands, particle size, crystal facets and dealloying are considered with a view to informing the theoretical feasibility to enhance the ORR activity. In addition, Pd-based alloys synthesized by different methods are presented and compared in terms of ORR activities. Future research directions are discussed and possible approaches to mass production for industrialization are also proposed.
This review provides an overview on Pd-based electrocatalysts for the oxygen reduction reaction (ORR) through the scientometric analysis and critical review methods. The main focus is on activity regulation and synthetic methods.
We use the class of commuting quantum computations known as IQP (instantaneous quantum polynomial time) to strengthen the conjecture that quantum computers are hard to simulate classically. We show ...that, if either of two plausible average-case hardness conjectures holds, then IQP computations are hard to simulate classically up to constant additive error. One conjecture relates to the hardness of estimating the complex-temperature partition function for random instances of the Ising model; the other concerns approximating the number of zeroes of random low-degree polynomials. We observe that both conjectures can be shown to be valid in the setting of worst-case complexity. We arrive at these conjectures by deriving spin-based generalizations of the boson sampling problem that avoid the so-called permanent anticoncentration conjecture.
Owing to the development of aqueous rechargeable zinc‐ion batteries (ZIBs), flexible ZIBs are deemed as potential candidates to power wearable electronics. ZIBs with solid‐state polymer electrolytes ...can not only maintain additional load‐bearing properties, but exhibit enhanced electrochemical properties by preventing dendrite formation and inhibiting cathode dissolution. Substantial efforts have been applied to polymer electrolytes by developing solid polymer electrolytes, hydrogel polymer electrolytes, and hybrid polymer electrolytes; however, the research of polymer electrolytes for ZIBs is still immature. Herein, the recent progress in polymer electrolytes is summarized by category for flexible ZIBs, especially hydrogel electrolytes, including their synthesis and characterization. Aiming to provide an insight from lab research to commercialization, the relevant challenges, device configurations, and life cycle analysis are consolidated. As flexible batteries, the majority of polymer electrolytes exploited so far only emphasizes the electrochemical performance but the mechanical behavior and interactions with the electrode materials have hardly been considered. Hence, strategies of combining softness and strength and the integration with electrodes are discussed for flexible ZIBs. A ranking index, combining both electrochemical and mechanical properties, is introduced. Future research directions are also covered to guide research toward the commercialization of flexible ZIBs.
An insight from lab research to commercialization for flexible zinc‐ion batteries is provided by comprehensively reviewing the development of polymer electrolytes, relevant challenges and strategies, and device configurations. Aiming to quantify the feasibility for commercialization, a ranking index is proposed combining both electrochemical and mechanical properties. Future research directions are also covered to guide research toward commercialization.
Electrocatalytic organic compound oxidation reactions (OCORs) have been intensively studied for energy and environmentally benign applications. However, relatively little effort has been devoted to ...developing a fundamental understanding of OCORs, including the detailed competition with side reactions and activity limitations, thus inhibiting the rational design of high-performance electrocatalysts. Herein, by taking the NiWO
4
-catalysed urea oxidation reaction (UOR) in aqueous media as an example, the competition between the OCOR and the oxygen evolution reaction (OER) within a wide potential range is examined. It is shown that the root of the competition can be ascribed to insufficient surface concentration of dynamic Ni
3+
, an active site shared by both the UOR and OER. A similar phenomenon is observed in other OCOR electrocatalysts and systems. To address the issue, a "controllable reconstruction of pseudo-crystalline bimetal oxides" design strategy is proposed to maximise the dynamic Ni
3+
population and manipulate the competition between the UOR and the OER. The optimised electrocatalyst delivers best-in-class performance and an ∼10-fold increase in current density at 1.6 V
versus
the reversible hydrogen electrode for alkaline urea electrolysis compared to those of the pristine materials.
A detrimental competition between the urea oxidation reaction (UOR) and oxygen evolution reaction is identified. Strategies are proposed to alleviate such competition and boost the performance of the UOR and other organic compound oxidation reactions.
The performance of lithium ion electrodes is hindered by unfavorable chemical heterogeneities that pre-exist or develop during operation. Time-resolved spatial descriptions are needed to understand ...the link between such heterogeneities and a cell's performance. Here, operando high-resolution X-ray diffraction-computed tomography is used to spatially and temporally quantify crystallographic heterogeneities within and between particles throughout both fresh and degraded Li
Mn
O
electrodes. This imaging technique facilitates identification of stoichiometric differences between particles and stoichiometric gradients and phase heterogeneities within particles. Through radial quantification of phase fractions, the response of distinct particles to lithiation is found to vary; most particles contain localized regions that transition to rock salt LiMnO
within the first cycle. Other particles contain monoclinic Li
MnO
near the surface and almost pure spinel Li
Mn
O
near the core. Following 150 cycles, concentrations of LiMnO
and Li
MnO
significantly increase and widely vary between particles.
...mental health services should be scaled up as an essential component of universal health coverage and should be fully integrated into the global response to other health priorities, including ...non-communicable diseases, maternal and child health, and HIV/AIDS. ...barriers and threats to mental health need to be addressed; these include the lack of awareness of the value of mental health in social and economic development, the lack of attention to mental health promotion and protection across sectors, the severe demand-side constraints for mental health care caused by stigma and discrimination, and the increasing threats to mental health due to global challenges such as climate change and growing inequality. ...mental health needs to be protected by public policies and developmental efforts; these intersectoral actions should be undertaken by each country's leaders to engage a wide range of stakeholders within and beyond health, including sectors in education, workplaces, social welfare, gender empowerment, child and youth services, criminal justice and development, and humanitarian assistance. ...investments in research and innovation should grow and harness novel approaches from diverse disciplines such as genomics, neuroscience, health services research, clinical sciences, and social sciences, both for implementation research on scaling up mental health interventions and for discovery research to advance understanding of causes and mechanisms of mental disorders and develop effective interventions to prevent and treat them.
Biometrics authentication for electronic payment is generally viewed as a quicker, convenient and a more secure means to identify and authenticate users for online payment. This view is mostly ...anecdotal and conceptual is nature. The aim of the paper is to shed light on the comparison of perceptions and beliefs of different authentication methods for electronic payment (i.e., credit card, credit card with PIN, and fingerprint biometrics authentication) in an e-commerce context. As theoretical foundation, the valence framework is used in understanding and explaining the individual's evaluation of benefit and risk concerning the payment methods. We propose a research model with hypotheses that evaluate and compare the individual's perceptions of the payment authentication methods, trust of the online store, and the willingness to continue using the website account associated with the payment authentication method. An experiment is used to test the hypotheses. The results show that biometrics authentication significantly influences the individual's security concern, perceived usefulness, and trust of online store. Theoretically, through the study's context – biometrics versus credit card authentication – evidence is provided for the importance of the individual's perceptions, concerns, and beliefs in the use of biometrics for electronic payments. Managerial implications include shedding light on the perceptions and concerns of secure authentication and the need for implementing biometrics authentication for electronic payments.
•Propose a model to compare a fingerprint-based biometrics authentication method with traditional authentication methods for e-payment•Empirically validate the proposed model using a data collected from an experiment-based survey•Show that biometrics authentication method significantly influences the individual’s security concern, perceived usefulness, and trust of online store.•Present managerial implications including the need for implementing biometrics authentication for electronic payments
As concerns about personal information privacy (PIP) continue to grow, an increasing number of studies have empirically investigated the phenomenon. However, researchers are not well informed about ...the shift of PIP research trends with time. In particular, there is a lack of understanding of what constructs have been studied in what contexts. As a result, researchers may design their study without sufficient guidance. This problem can lead to unproductive efforts in advancing PIP research. Therefore, it is important and timely to review prior PIP research to enhance our understanding of how it has evolved. We are particularly interested in understanding the chronological changes in contexts and research constructs studied. We use a chronological stage model of PIP research we develop, a set of contextual variables identified from prior literature, and the four-party PIP model suggested by Conger et al. (2013) as theoretical foundations to conduct a chronological literature review of empirical PIP concern studies. We find several PIP research trends during the last two decades, such as the quantity of PIP research has drastically increased; the variety of contexts and research constructs being studied has increased substantially; and many constructs have been studied only once while only a few have been repeatedly studied. We also find that the focus of PIP research has shifted from general/unspecified contexts to specific ones. We discuss the contributions of the study and recommendations for future research directions. We propose a fifth party as an emergent player in the ecosystem of PIP and call for future research that investigates it.
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