The single-crystal cathode materials exhibit better cyclic stability, enhanced compaction density, and improved safety than polycrystalline cathode materials. They, therefore, are ideal cathode ...material candidates for lithium-ion batteries. Introducing hetero materials, excessive sintering temperature and tedious steps during the synthesis of the single-crystal cathode materials, however, limit their large-scale application. In this work, we adopt the spray pyrolysis method to prepare the hybrid oxides NiO–MnCo2O4–Ni6MnO8. This kind of hybrid oxides is considered to be an ideal precursor for the single-crystal Ni-rich cathode materials owing to its fine particle size and porous structure. Subsequently, high-temperature lithiation synthesises the submicron single-crystal LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material. The synthesis temperature of the submicron single-crystal NCM811 is significantly lowered when LiNO3 is selected as the lithium source and serves as the flux agent taking advantage of its fusibility. Consequently, the as-synthesized submicron single-crystal NCM811, compared with conventional polycrystalline NCM811, exhibits long lifetime applications, improved thermal stability and micro-crack immunity. The synthetic strategy in this work also demonstrates that the crystal crushing process, flux adding, and repeated sintering are not indispensable in the synthesis of single-crystal cathode materials.
•The spray pyrolysis method is adopted to synthesize Ni0.8Co0.1Mn0.1O1.1 precursor.•A novel strategy are developed to synthesize the single-crystal NCM811.•Single-crystal particles prevent the generation of intergranular cracks.
As a novel aero-engine concept,adaptive cycle aero-engines（ACEs） are attracting wide attention in the international aviation industry due to their potential superior task adaptability along a wide ...flight regime.However,this superior task adaptability can only be demonstrated through proper combined engine control schedule design.It has resulted in an urgent need to investigate the effect of each variable geometry modulation on engine performance and stability.Thus,the aim of this paper is to predict and discuss the effect of each variable geometry modulation on the matching relationship between engine components as well as the overall engine performance at different operating modes,on the basis of a newly developed nonlinear component-based ACE performance model.Results show that at all four working modes,turning down the high pressure compressor variable stator vane,the low pressure turbine variable nozzle,the nozzle throat area,and turning up the core-driven fan stage variable stator vane,the high pressure turbine variable nozzle can increase the thrust at the expense of a higher high pressure turbine inlet total temperature.However,the influences of these adjustments on the trends of various engine components＇ working points and working lines as well as the ratio of the rotation speed difference are different from each other.The above results provide valuable guidance and advice for engine combined control schedule design.
► Cr-Mg substituted LiNi0.8Co0.1Mn0.1O2 was synthesized by fast co-precipitation. ► Rietveld refinements show that Cr-Mg substitution suppresses the cation-mixing. ► Cr-Mg substituted samples exhibit ...superior electrochemical performance.
Cr and Mg co-substituted LiNi0.8Co0.1Mn0.1O2 samples are synthesized by fast co-precipitation method and characterized by scanning electron microscope, X-ray diffraction, Rietveld refinement and electrochemical measurements. The Rietveld refinement results show that suitable Cr and Mg co-substitution could lead to synergistic reaction to form a kind of complementary structure, by full Cr occupying in Ni layer, and full Mg occupying in Li layer, respectively, and further attribute to highly ordered layered LiNi0.8Co0.1Mn0.1O2 with low cation mixing degree. Electrochemical studies demonstrate that Cr and Mg co-substitution in LiNi0.8Co0.1Mn0.1O2 also result in improved discharge capacity, initial coulombic efficiency, rate ability and cycling property compared to pristine LiNi0.8Co0.1Mn0.1O2. The improvements of electrochemical property resulted from the stabilized host structure by Cr and Mg incorporation into LiNi0.8Co0.1Mn0.1O2.
Carbon nanotubes (CNTs), which exhibit stable surfaces under acidic, neutral and alkaline solutions, provide an ideal platform for studying the nature of oxygen evolution reaction (OER) mechanisms at ...different pH. Here, OER on four types of pristine carbon nanotubes (CNTs) with walls from single-walled, double-walled, three-walled to multi-walled were studied in acid, neutral and alkaline conditions. Mechanism and kinetics study reveals that the OER on all CNTs is constrained by the water deprotonation in acid and neutral conditions,resulting in high Tafel slopes close to 240 mV dec−1, high overpotentials (0.7–1 V), and approaching zeroth-reaction-order to H+/OH−. The kinetics and mechanism shift at pH ∼9–10 due to competition discharge between H2O and OH−. The Tafel slopes decrease, and the reaction orders increase with the increase of OH− concentration. The higher kinetics and enhanced activities for CNTs with 2–4 walls support the proposed tunneling effect, highlighting the favourable electron transfer pathway between the outer wall and inner tubes. The finding will provide a new direction for designing highly efficient OER catalysts.
The paper reports the preparation of nanostructured LiFePO4 cathode with high performance by a phase transition process from the tavorite LiFePO4OH structure to the olivine LiFePO4 structure at ...low-temperature. On the premise of the lattice maturity, a lower crystallization temperature is conducive to synthesizing LiFePO4 with optimal unit cell, crystalline size, and electrochemical property, as well as reducing energy consumption of production.
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•High performance LiFePO4 was obtained by a novel LiFePO4OH precursor at 550–600 °C.•The desirable LiFePO4OH precursor was prepared via a wet pre-lithiation process.•The mechanisms affecting the electrochemical performance of LiFePO4 have been studied.
The main problem currently faced in the large-scale production of LiFePO4 by solid-phase methods is the high energy consumption caused by solid/melt-phase lithiation process. Herein, LiFePO4 nanoparticles are successfully obtained by a phase transition from the tavorite LiFePO4OH structure to the olivine LiFePO4 structure at low-temperature (550–600 °C). This desirable LiFePO4OH precursor is prepared via a wet pre-lithiation process, and its thermodynamic feasibility is demonstrated by thermodynamic calculation. The liquid-phase lithiation followed by a simple carbothermal reduction process (c.f., the solid/melt-phase lithiation process of the traditional solid-state method) results in a superior mass transfer efficiency and reaction uniformity. It therefore prevents the requirement for a higher temperature and longer sintering process. It is also indicated that on the premise of the lattice perfection, a lower crystallization temperature is not only conducive to widening the effective ion diffusion channels of LFP, inhibiting further crystal growth, and shortening the diffusion path, but it also reduces the synthetic cost. As a result, a crystallization temperature of 600 °C (or 550 °C) is optimal, and the resulting LiFePO4 electrode can deliver an appealing high rate capacity of 147.7 mA h g−1 at 10 C. It is expected that this novel synthetic route could be employed for the large-scale commercial production of high performance LiFePO4 cathode materials at a low cost.
The mechanical and dynamic mechanical properties, interface adhesion and microstructures of the amino silicone oil emulsion (ASO) modified short ramie fiber reinforced polypropylene composites ...(RFPCs) with different fiber fractions were investigated. The RFPCs were made through a combined process of extrusion and injection molding. Mechanical property tests of the RFPCs revealed enhancements in tensile and flexural strengths with increase of the fiber fraction due to the high stiffness of the fiber filler and a better interfacial bonding from ASO treatment. The dynamic mechanical analysis (DMA) results indicated that fiber incorporation plays an important role in DMA parameters (storage modulus, loss modulus, and damping ratio) at Tg by forming an improved interfacial adhesion and providing more effective stress transfer rate and energy dissipation between matrix and fiber. The phase behavior analysis suggests all the RFPCs are a kind of heterogeneity system based on the Cole-Cole plot analysis.
Iron oxide has been considered as one of the most promising anode materials for lithium-ion batteries (LIBs) due to its low cost, environmental benignity, and abundant source. However, the huge ...volume variation of iron oxide during the lithiation/delithiation processes has caused a structural failure and decay of the electrochemical performance for LIBs. In order to improve the electrochemical performance of iron oxide, one efficient strategy is to prepare carbon-coated iron oxide with special structure. Herein, we use metal-organic frameworks to prepare Fe
3
O
4
/reduced graphene oxide (rGO) nanocomposite through a hydrothermal route. As an anode material of LIBs, the prepared Fe
3
O
4
/rGO nanocomposite exhibits a high discharge capacity of 1762.1 mAh g
−1
and remarkably good rate performance with a charge capacity of 1060.6 mAh g
−1
at 100 mA g
−1
and 772.9 mAh g
−1
at 1000 mA g
−1
. In the Fe
3
O
4
/rGO composite, the electrical conductivity was enhanced and the volume expansion was also restrained by rGO.
: Depression is a sickening psychiatric condition that is prevalent worldwide. To manage depression, the underlying modes of antidepressant effect of herbals are important to be explored for the ...development of natural drugs. Tiansi Liquid is a traditional Chinese medicine (TCM) that is prescribed for the management of depression, however its underlying mechanism of action is still uncertain. The purpose of this study was to systematically investigate the pharmacological mode of action of a herbal formula used in TCM for the treatment of depression.
: Based on literature search, an ingredients-targets database was developed for Tiansi Liquid, followed by the identification of targets related to depression. The interaction between these targets was evaluated on the basis of protein-protein interaction network constructed by STITCH and gene ontology (GO) enrichment analysis using ClueGO plugin.
: As a result of literature search, 57 components in Tiansi Liquid formula and 106 potential targets of these ingredients were retrieved. A careful screening of these targets led to the identification of 42 potential targets associated with depression. Ultimately, 327 GO terms were found by analysis of gene functional annotation clusters and abundance value of these targets. Most of these terms were found to be closely related to depression. A significant number of protein targets such as IL10, MAPK1, PTGS2, AKT1, APOE, PPARA, MAPK1, MIF, NOS3 and TNF-α were found to be involved in the functioning of Tiansi Liquid against depression.
: The findings elaborate that Tiansi Liquid can be utilized to manage depression, however, multiple molecular mechanisms of action could be proposed for this effect. The observed core mechanisms could be the sensory perception of pain, regulation of lipid transport and lipopolysaccharide-mediated signaling pathway.
In this paper, the microstructure and mechanical properties of SLM-GH3230 superalloy treated by different post treatments (single hot isostatic pressing and heat treatments after hot isostatic ...pressing) were studied. The micro-morphologies show that the grains along building direction after HIP + HT are mainly columnar grains, which is consistent to that after single HIP. The granular precipitates distribute intergranularly and intragranularly after HIP, but gradually re-dissolve into matrix with the increase of the temperature of the post HT processes. XRD and EDS analyses results indicate that the matrix mainly consists of austenitic γ phase and the granular precipitates are mainly M6C carbides enriched in W element. The average grain size decreases after HT compared to that after HIP, and the crystallographic orientation of grains tends to be more uniform. The Vickers hardness decreases after HIP and HIP + HT processes within a certain degree. According to tensile test results, the sample shows a better combination of strength and plastic performance under HIP+1250 °C/30 min processing, which can also be verified by the characteristic of the fracture morphology with more tearing dimples.
•GH3230 superalloys were fabricated by selective laser melting technology.•The evolution states of the grains and precipitates were characterized.•A better combination of strength and plasticity was gained after HIP+1250 °C/30 min.•The impact mechanism of precipitates on mechanical properties was discussed.
Sodium-ion batteries (SIBs) with huge cost advantages will show extraordinary talents in low-speed electric vehicles, energy storage, and base station communications. Manganese oxides are promising ...candidates for cathode materials, rapid capacity decay, and poor electrochemical performance that limit its commercial applications. Here, the nanosheets with exposed active crystal planes are prepared through a simple NH
3
∙H
2
O-assisted sol-gel process and subsequent high-temperature calcination. The unique structure considerably reduces the Na
+
diffusion path for the excellent Na
+
diffusion kinetics. The final results confirm that the NMO-pH6 sample, exposed to the active planes, has high energy density (557.9 Wh kg
−1
at 0.1 C) and outstanding electrochemical performance, especially the rate performance (93.8 mAh g
−1
at 5 C and 79.95 %, 100 cycles at 1 C). More importantly, it will facilitate the further construction of advanced cathode materials for high-performance SIBs.
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