All-solid-state flexible asymmetric supercapacitors with high energy and power densities based on NiCo_2S_4@MnS and active carbon

Electrode material based on a novel core–shell structure consisting of NiCoS（NCS） solid fiber core and Mn S（MS） sheet shell（NCS@MS） in situ grown on carbon cloth（CC） has been successfully prepared by a simple sulfurization-assisted hydrothermal method for high performance supercapacitor. The synthesized NiCoS@Mn S/CC electrode shows high capacitance of 1908.3 F gat a current density of 0.5 A gwhich is higher than those of NiCoSand Mn S at the same current density. A flexible all-solid-state asymmetric supercapacitor（ASC） is constructed by using NiCoS@Mn S/CC as positive electrode, active carbon/CC as negative electrode and KOH/poly（vinyl alcohol）(PVA) as electrolyte. The optimized ASC shows a maximum energy density of 23.3 Wh kgat 1 A g, a maximum power density of about7.5 kw kgat 10 A gand remarkable cycling stability. After 9000 cycles, the ASC still exhibited67.8% retention rate and largely unchanged charge/discharge curves. The excellent electrochemical properties are resulted from the novel core–shell structure of the NiCoS@Mn S/CC electrode, which possesses both high surface area for Faraday redox reaction and superior kinetics of charge transport. The NiCoS@Mn S/CC electrode shows a promising potential for energy storage applications in the future.

Identifying Heteroatomic and Defective Sites in Carbon with Dual-Ion Adsorption Capability for High Energy and Power Zinc Ion Capacitor

Aqueous zinc-based batteries(AZB s)attract tremendous attention due to the abundant and rechargeable zinc anode.Nonetheless,the requirement of high energy and power densities raises great challenge for the cathode development.Herein we construct an aqueous zinc ion capacitor possessing an unrivaled combination of high energy and power characteristics by employing a unique dual-ion adsorption mechanism in the cathode side.Through a templating/activating co-assisted carbonization procedure,a routine protein-rich biomass transforms into defect-rich carbon with immense surface area of 3657.5 m^(2) g^(-1) and electrochemically active heteroatom content of 8.0 at%.Comprehensive characterization and DFT calculations reveal that the obtained carbon cathode exhibits capacitive charge adsorptions toward both the cations and anions,which regularly occur at the specific sites of heteroatom moieties and lattice defects upon different depths of discharge/charge.The dual-ion adsorption mechanism endows the assembled cells with maximum capacity of 257 mAh g^(-1) and retention of72 mAh g^(-1) at ultrahigh current density of 100 A g^(-1)(400 C),corresponding to the outstanding energy and power of 168 Wh kg^(-1)and 61,700 W kg^(-1).Furthermore,practical battery configurations of solid-state pouch and cable-type cells display excellent reliability in electrochemistry as flexible and knittable power sources.

Analysis of the trend of global power sources based on comment emotion mining

In recent years,renewable energy technologies have been developed vigorously,and related supporting policies have been issued.The developmental trend of different energy sources directly affects the future developmental pattern of the energy and power industry.Energy trend research can be quantified through data statistics and model calculations;however,parameter settings and optimization are difficult,and the analysis results sometimes do not reflect objective reality.This paper proposes an energy and power information analysis method based on emotion mining.This method collects energy commentary news and literature reports from many authoritative media around the world and builds a convolutional neural network model and a text analysis model for topic classification and positive/negative emotion evaluation,which helps obtain text evaluation matrixes for all collected texts.Finally,a long-short-term memory model algorithm is employed to predict the future development prospects and market trends for various types of energy based on the analyzed emotions in different time spans.Experimental results indicate that energy trend analysis based on this method is consistent with the real scenario,has good applicability,and can provide a useful reference for the development of energy and power resources and of other industry areas as well.

Revisiting the electrode manufacturing: A look into electrode rheology and active material microenvironment

The microstructures on electrode level are crucial for battery performance, but the ambiguous understanding of both electrode microstructures and their structuring process causes critical challenges in controlling and evaluating the electrode quality during fabrication. In this review, analogous to the cell microenvironment well-known in biology, we introduce the concept of ‘‘active material microenvironment”(ME@AM)that is built by the ion/electron transport structures surrounding the AMs, for better understanding the significance of the electrode microstructures. Further, the scientific significance of electrode processing for electrode quality control is highlighted by its strong links to the structuring and quality control of ME@AM. Meanwhile, the roles of electrode rheology in both electrode structuring and structural characterizations involved in the entire electrode manufacturing process(i.e., slurry preparation, coating/printing/extrusion, drying and calendering) are specifically detailed. The advantages of electrode rheology testing on in-situ characterizations of the electrode qualities/structures are emphasized. This review provides a glimpse of the electrode rheology engaged in electrode manufacturing process and new insights into the understanding and effective regulation of electrode microstructures for future high-performance batteries.

Measurement of Particle Velocity, Particle Size Distribution and Concentration in Particulate Suspension by Transmission Fluctuation Correlation Spectrometry

In coal-fired power generation industry, parameters such as particle size affect combustion efficiency. Especially in the application of two-phase flow clean energy, the parameters such as particle velocity, particle size distribution and concentration are very important, because the coal particle velocity, concentration or size range have an impact on the whole combustion process. This paper introduces an optical measurement setup based on the transmission fluctuation correlation spectrum measurement technique, which realizes the simultaneous measurement of particle velocity, particle size distribution and concentration. Compared with image method, ultrasonic spectrum method and other methods, the experimental device is simple and low-cost.

Low-carbon Operation of Combined Heat and Power Integrated Plants Based on Solar-assisted Carbon Capture

Accelerating the development of renewable energy and reducing CO_(2)emissions have become a general consensus and concerted action of all countries in the world. The electric power industry, especially thermal power industry, is the main source for fossil energy consumption and CO_(2)emissions. Since solvent-based post-combustion carbon capture technology would bring massive extra energy consumption, the application of solar-assisted carbon capture technology has attracted extensive attention. Due to the important role of coal-fired combined heat and power plants for serving residential and industrial heating districts, in this paper, the low-carbon operation benefits of combined heat and power integrated plants based on solar-assisted carbon capture(CHPIP-SACC) are fully evaluated in heat and power integrated energy system with a high proportion of wind power. Based on the selected integration scheme, a linear operation model of CHPIP-SACC is developed considering energy flow characteristics and thermal coupling interaction of its internal modules. From the perspective of system-level operation optimization, the day-ahead economic dispatch problem based on a mix-integer linear programming model is presented to evaluate the low-carbon benefits of CHPIP-SACC during annual operation simulation. The numerical simulations on a modified IEEE 39-bus system demonstrate the effectiveness of CHPIP-SACC for reducing CO_(2)emissions as well as increasing the downward flexibility. The impact of different solar field areas and unit prices of coal on the low-carbon operation benefits of CHPIP-SACC is studied in the section of sensitivity analysis.

Rational construction of phosphate layer to optimize Cu-regulated Fe_(3)O_(4) as anode material with promoted energy storage performance for rechargeable Ni-Fe batteries

Flexible aqueous energy storage devices with high security and flexibility are crucial for the progress of wearable energy storage.Particularly,aqueous rechargeable Ni-Fe batteries owning a large theoretical capacity,low cost and outstanding safety characteristics have emerged as a promising candidate for flexible aqueous energy storage devices.Herein,Cu-doped Fe_(3)O_(4)(CFO)with 3D coral structure was prepared by doping Cu^(2+) based on Fe_(3)O_(4)nanosheets(FO).Furthermore,the Fe-based anode material(CFPO)grown on carbon fibers was obtained by reconstructing the surface of CFO to form a low-crystallization shell which can enhance the ion transport.Excitingly,the newly developed CFPO electrode as an innovative anode material further exhibited a high capacity of 117.5 mAh g^(-1)(or 423 F g^(-1))at 1 A g^(-1).Then,the assembled aqueous Ni-Fe batteries with a high cell-voltage output of 1.6 V deliver a high capacity of 49.02 mAh g^(-1) at 1 A g^(-1) and retention ratio of 96.8%for capacitance after 10000 continuous cycles.What’s more,the aqueous quasi-solid-state batteries present a remarkable maximal energy density of 45.6 Wh kg^(-1) and a power density of 12 kW kg^(-1).This work provides an innovative and feasible way and optimization idea for the design of high-performance Fe-based anodes,and may promote the development of a new generation of flexible aqueous Ni-Fe batteries.

Effects of dimethyl ether on soot formation in premixed laminar flame by laser induced incandescence method

The control of PM emission is a rather complicated problem to be solved both for diesel engine and GDI engines.There are vast factors affecting PM emission,the fuel,A/F,combustion temperature and so on.But undoubtedly,most efforts are paid to exhaust aftertreatment,rather than the control of generation.This paper is to investigate the effect of dimethyl ether(DME,CH3OCH3)on soot generation in flame.Therefore,a laser induced incandescence(LII)measurement system for soot volume concentration measurements in flame is used.Two DME gaseous mixtures were prepared with equivalence ratios 1 and 2.To highlight its effect on soot formation,acetylene known as the precursor of soot,is added in different ratios.Similarly,CO2 is mixed to simulate exhaust gas recycling(EGR)effect in engines.The experimental results indicate that the fuel property and A/F ratio are the dominating factors for the generation of soot during combustion.The combustion of DME doesn't emit soot obviously even under rich mixture condition.When burning the mixture of DME and acetylene(C2H2)in different proportion,there is barely soot emission at equivalence ratio of 1.The soot emission increases as the proportion of C2H2 increases at equivalence ratio 2,and the DME addition reduces the soot emission of C2H2 flame.CO2 dilution doesn't lead to the increase of soot when burning DME at equivalence 1 and 2.Soot emission is lower when the mixture of DME and acetylene is diluted by CO2,though soot volume concentration increases slightly as the proportion of C2H2 increases.The kinetic analysis indicates that the combustion of DME does not produce the precursor of soot.Under fuel-rich combustion conditions,C2H2 reacts with H radical to form C2H3,which leads to soot.When DME is added,it competes for H radical,which reduces the formation of C2H3 and thus reduces soot formation.The research carried out in this paper indicates that DME fuel has obviously power to reduce soot formation during combustion,no matter whether it is diluted by CO2 or mixed with soot precursor substance C2 H2.

增大分级结构碳纳米笼的离子传输微孔通道获得超高的能量密度和功率密度

提升超级电容器能量密度而不牺牲其高功率密度是能源存储领域的不懈追求.离子液体电解液具有大的工作电压窗口,以其为电解液可提升超级电容器能量密度.但离子液体离子尺寸大、离子电导率低且粘度高,通常会导致超级电容器功率密度的减小.本文主要通过增大分级结构碳纳米笼(hCNC)电极材料的离子传输微孔通道,实现了在EMIMBF4离子液体电解液中超级电容器能量密度和功率密度的协同提升.通过Boudouard反应,在保持hCNC独特分级结构的前提下调节了贯穿碳纳米笼壁的微孔尺寸,同时,在优化的活化温度下hCNC的比表面积、孔体积和导电性均得以提升.这种独特的调节促进了大尺寸离子的传输,有效降低了等效串联电阻,从而显著提升了超级电容器的性能.优化的样品在功率密度为1.8 kW kg^(-1)时的能量密度高达153.8 W h kg^(-1),在超高功率密度480.1 kW kg^(-1)时能量密度仍能保持54.0 W h kg^(-1).本研究展示了一种通过精细调控材料微孔及相关性质开发先进电极材料的有效方法.