A critical challenge for the practical use of the layered O3-type binary nickel manganese oxides for sodium-ion batteries is the poor structural stability during extended cycling. The approaches of ...constructing O3/P2 hybrid composites can partially improve the cycling stability, but general approaches sacrifice the advantages of high capacity and low cost of the O3-type cathodes due to excessive sodium deficiency and lithium substitution. Here, we rationally design a serial of novel O3-majority hybrid Na0.9-xNi0.45Mn0.55O2 (x = 0.02, 0.04 and 0.08) cathodes, which exhibit high capacities while maintaining exceptional long-term stability. Particularly, the optimized O3/P2 Na0.88Ni0.45Mn0.55O2 composite delivers 106.7 mA h·g−1 with 71.1% capacity retention after 250 cycles at 1 C (1C = 150 mA g−1), the cyclability is 32% higher than that of the O3Na0.9Ni0.45Mn0.55O2 cathode; and it also delivers a initial discharge capacity of 75.9 mA h·g−1, maintaining 72.4% capacity retention after 1000 cycles at 10 C. More importantly, the post-cycling analyses demonstrate O3/P2 hybrid phases successfully suppress the structural degradation of Na0.9Ni0.45Mn0.55O2 during battery operation. This study provides new perspectives in designing high performance cathodes for sodium-ion batteries.
•This work reports a novel O3-majority hybrid Na0.88Ni0.45Mn0.55O2 cathode.•O3 phase and P2 phase grow with an intergrowth interfaces.•The O3/P2 hybrid Na0.88Ni0.45Mn0.55O2 shows superior electrochemical performance.•The major O3 phase guarantees a high specific capacity.•The O3/P2 hybrid phases suppress structural and electrochemical degradation.
The development of the layered cathode material for sodium ion batteries are hindered by synthesis approaches. The sol-gel method is a promising way to prepare the cathodes due to the advantage of ...mixing the raw product at atomic or molecular level, while the selection criteria for complexing agents are still unclear. Herein, the Na0.9Ni0.45Mn0.55O2 cathode is successfully prepared via sol-gel method, by using sucrose, glucose, citric acid, and ethylene diamine tetra-acetic acid as the chelating agent, respectively. The effects of different chelating agents on the morphologies, structural and electrochemical properties are studied in detail. Electrochemical properties prove that the sample using citric acid shows the best electrochemical performance, delivering a capacity of 96 mAh g−1 and 48% retention after 300 cycles at 1C, and 59.6 mAh g−1 of capacity at 10 C rate, which are significantly higher than those of the other samples. XRD and HRTEM are conducted for the cycled electrodes, which demonstrate that the structure of the optimized sample maintains better phase stability and interfacial stability. This work is of considerable significance in understanding the selection criteria for the synthesis of layered cathode chelators for sodium-ion batteries by the sol-gel method.
•Layered Na0.9Ni0.45Mn0.55O2 is prepared via sol-gel method.•The effect of the chelating agents on the Na0.9Ni0.45Mn0.55O2 are discussed.•Citric acid assisted Na0.9Ni0.45Mn0.55O2 shows superior electrochemical properties.•Citric acid assisted Na0.9Ni0.45Mn0.55O2 exhibits well dynamic behavior.•Citric acid can fix more sodium and thus obtaining a stable structure.
Ni-rich cathode materials, one of the most promising cathodes for high-energy lithium-ion batteries, are still suffered from interfacial instability and bulk degradation. Herein, Zr-doped and ...Li6Zr2O7-coated LiNi0.8Co0.1Mn0.1O2 cathode, and Zr-doped Li6Zr2O7–LiNi0.8Co0.1Mn0.1O2 composite are successfully prepared via a smart one-step calcination process. The attained dual-modified architecture allows the optimized sample exhibiting enhanced rate performance while maintaining long-term stability at room temperature (82.13% after 200 cycles at 1 C rate) and even at elevated temperature. Further studies reveal that the delayed temperature-driven phase transition and the suppressed interfacial degradation can be addressed with the synergetic effects provided by the Zr-doping and Li6Zr2O7-coating. The Zr doping could improve bulk stability by reducing cation disorder. The conductive Li6Zr2O7 surface coating enhances the interfacial stability of the cathode materials while improving the electrochemical kinetics. This smart modification strategy renders Zr modification a viable modification method to enhance the electrochemical performance and structural properties of Ni-rich cathode materials.
Lithium ion batteries have been powering our daily life from portable electronic devices to electric vehicles 1–3. The lack of cathode materials with high reversible capacities and high thermal stability is still a restriction for the development of high-energy LIBs. Among the adopting options as an alternative to traditional LiCoO2 material, the layered Ni-rich ternary materials LiNixCoyMn1-x-yO2 (x≥0.5) are considered as promising candidates because of their increased energy densities and reduced cost 4–7. Specially, LiNi0.8Co0.1Mn0.1O2 (NCM) has been attracting much attention by virtue of high specific capacity of delivering more than 200 mAh•g−1 of discharge capacity 8–11.
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SUMMARY
In plants so‐called plasma membrane intrinsic proteins (PIPs) are major water channels governing plant water status. Membrane trafficking contributes to functional regulation of major PIPs ...and is crucial for abiotic stress resilience. Arabidopsis PIP2;1 is rapidly internalised from the plasma membrane in response to high salinity to regulate osmotic water transport, but knowledge of the underlying mechanisms is fragmentary. Here we show that PIP2;1 occurs in complex with SYNTAXIN OF PLANTS 132 (SYP132) together with the plasma membrane H+‐ATPase AHA1 as evidenced through in vivo and in vitro analysis. SYP132 is a multifaceted vesicle trafficking protein, known to interact with AHA1 and promote endocytosis to impact growth and pathogen defence. Tracking native proteins in immunoblot analysis, we found that salinity stress enhances SYP132 interactions with PIP2;1 and PIP2;2 isoforms to promote redistribution of the water channels away from the plasma membrane. Concurrently, AHA1 binding within the SYP132‐complex was significantly reduced under salinity stress and increased the density of AHA1 proteins at the plasma membrane in leaf tissue. Manipulating SYP132 function in Arabidopsis thaliana enhanced resilience to salinity stress and analysis in heterologous systems suggested that the SNARE influences PIP2;1 osmotic water permeability. We propose therefore that SYP132 coordinates AHA1 and PIP2;1 abundance at the plasma membrane and influences leaf hydraulics to regulate plant responses to abiotic stress signals.
Significance Statement
We uncover a new role for the plasma membrane trafficking SNARE SYP132 in the regulation of PIP2;1 density and function in response to salinity and osmotic stress. Remarkably these pathways appear to intersect with coordinate regulation of AHA1 that is governed by the SYP132 during pathogenesis, thus suggesting that the SNARE is at the centre of an antiparallel association of PIP2 and the H+‐ATPase affected by salinity.
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•Ce-doped and CeO2-coated LiNi0.5Co0.2Mn0.3O2 cathode is synthesized via a simple route.•Ce-doping can reduce the degree of cation mixing by 0.5%.•The capacity retention of ...Ce-modified NCM cathode is increased by 9.6%.•The 2% Ce-modified sample shows the best Li+ diffusion coefficient.
The well-established LiNi0.5Co0.2Mn0.3O2 (NCM523) cathode materials possess a broad prospect for Li-ion batteries. However, the NCM523 still suffers severe capacity fading and structural instability. In this research, Ce-doped and CeO2-coated NCM523 cathode materials are synthesized by a smart one-step calcination process. It is found that the CeO2 coating layer is formed during high-temperature calcination. The CeO2 coating layers stop the electrode from being exposed to the electrolyte directly and promote the kinetics of lithium deintercalation. Besides, Ce doping could suppress the bulk cation-mixing degree. Electrochemical tests suggest that Ce-modification improves the capacity retention of cathode materials. The optimized Ce-modification cathode material, among 2.7 V and 4.6 V, not only shows the best capacity retention of 76.2%, but also delivers a discharge capacity of 178.2 mAh g−1 at 1 C. This smart modification strategy provides novel ideas for advanced LIBs.
A critical challenge in the commercialization of layer-structured Ni-rich materials is the fast capacity drop and voltage fading due to the interfacial instability and bulk structural degradation of ...the cathodes during battery operation. Herein, with the guidance of theoretical calculations of migration energy difference between La and Ti from the surface to the inside of LiNi0.8Co0.1Mn0.1O2, for the first time, Ti-doped and La4NiLiO8-coated LiNi0.8Co0.1Mn0.1O2 cathodes are rationally designed and prepared, via a simple and convenient dual-modification strategy of synchronous synthesis and in situ modification. Impressively, the dual modified materials show remarkably improved electrochemical performance and largely suppressed voltage fading, even under exertive operational conditions at elevated temperature and under extended cutoff voltage. Further studies reveal that the nanoscale structural degradation on material surfaces and the appearance of intergranular cracks associated with the inconsistent evolution of structural degradation at the particle level can be effectively suppressed by the synergetic effect of the conductive La4NiLiO8 coating layer and the strong Ti—O bond. The present work demonstrates that our strategy can simultaneously address the two issues with respect to interfacial instability and bulk structural degradation, and it represents a significant progress in the development of advanced cathode materials for high-performance lithium-ion batteries.
Cell Outage Management (COM) is a functionality aiming to automatically detect and mitigate outages that occur in radio networks due to unexpected failures. In this paper, we assume that future Radio ...Access Networks (RAN) can autonomously detect an outage based on measurements, then we propose a Genetic Algorithm (GA) based mechanism for Cell Outage Compensation (COC). COC is achieved by a GA- based COC mechanism. Simulation results showed that with GA, the network performance degradation is minimized.
The number of Android applications has increased rapidly as Android is becoming the dominant platform in the smartphone market. Security and privacy are key factors for an Android application to be ...successful. Android provides a permission mechanism to ensure security and privacy. This permission mech- anism requires that developers declare the sensitive resources required by their applications. On installation or during runtime, users are required to agree with the permission request. However, in practice, there are numerous popular permission misuses, despite Android introducing official documents stating how to use these permissions properly. Some data mining techniques （e.g., association rule mining） have been proposed to help better recommend permissions required by an API. In this paper, based on popular techniques used to build recommendation systems, we propose two novel approaches to improve the effectiveness of the prior work. The first approach utilizes a collaborative filtering technique, which is inspired by the intuition that apps that have similar features -- inferred from their APIs -- usually share similar permissions. The second approach recom- mends permissions based on a text mining technique that uses a naive Bayes multinomial classification algorithm to build a prediction model by analyzing descriptions of apps. To evaluate these two approaches, we use 936 Android apps from F-Droid, which is a repository of free and open source Android applications. We find that our proposed approaches yield a significant improvement in terms of precision, recall, Fl-score, and MAP of the top-k results over the baseline approach.
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