Enhanced Storage Capacity Research Articles

Influence of the production method on the thermophysical properties of high temperature molten salt-based nanofluids

The potential use of molten salt-based nanofluids as thermal energy storage material in Concentrated Solar Power plants has gained attention over the last years due to their enhanced storage capacity. The possible effects of the salt-based nanofluid production at industrial scale have not been yet investigated, as this could influence the nanoparticles agglomeration and therefore their thermal and flow properties. Four methods were evaluated for the production of solar salt-based nanofluids containing 1 wt% of silica nanoparticles. The particle size distribution, the stability, the rheological behaviour and the specific heat of the samples were measured. Nanofluids prepared by means of a dry mixing method presented the lowest viscosity, trimodal particle size distribution and lack of stability. The commonly used dissolution method coupled with oven drying in a petri dish as well as the ball milling method presented non-Newtonian behaviour and intermediate values of particle size and stability. The new spray drying method proposed provided a monomodal particle size distribution with high stability but the highest viscosity and shear thickening behaviour. Results suggest that the four methods evaluated are appropriate for specific heat enhancement (up to 21.1%) but a commitment between stability and viscosity has to be achieved.

Effect of nanoparticles in molten salts – MD simulations and experimental study

Highlighted experimental studies on nanofluids reveal an anomalous increment in the specific heat capacity (Cp) of these ionic systems when nanoparticles are added. This fact is really important due the applicability of nanofluids in concentrating solar power plants as heat transfer fluid and storage media. These are promising results for the development of high-temperature heat storage applications by enhanced storage capacity materials. The present work focuses on the study of this effect in NaNO3 molten salt doped with SiO2 nanoparticles by molecular dynamics (MD) simulations and Differential Scanning Calorimetry (DSC) experiments. The study shows that for nanoparticles’ concentrations around 1% wt. the Cp increases by 26% compared to pure NaNO3, whereas at higher concentrations the effect disappears. The results approach high agreement between experimental and simulation results and MD simulations reveal that the increase of Cp at low concentrations is explained by the formation of a semi ordered layer of ionic fluid. This layer is rich in Na+ cations, around the nanoparticles whereas the reduction of Cp at concentrations higher than 2% wt. is related to the aggregation of nanoparticles as revealed by Scanning Electron Microscopy (SEM). However, deep experimental results with other materials will be required in order to validate the layering effect.

Towards natural water cycle in urban areas: Modelling stormwater management designs

ABSTRACT Urbanization modifies the natural water cycle particularly by reducing the water storage capacity. We analysed the storage capacity of three stormwater management designs in south-western Finland to demonstrate how an urban catchment releases stormwater and how storage contributes to flood resilience. The analysis relies on EPA SWMM5.1 simulations of water balance for a seven-month period including two extreme rain events during the summer and autumn. The enhanced storage capacity provided by the designs increased resilience against flooding and released stormwater with slower rates leading to reduced peak flows. Even the design with the least storage (10% LID coverage) was efficient at regulating floods due to controlled flow in a vegetated swale, whereas the design with the highest storage capacity (60% LID coverage) demonstrated the possibility of restoring nearly natural water cycle in urban catchments. The study suggests storage capacity can act as a flood resilience indicator directly linked with the physical catchment characteristics.

Trust in Management Information Systems (MIS)

Abstract. Digitalization, enhanced storage capacities, and the Internet of Things increase the volume of data in modern organizations. To process and make use of these data and to avoid information overload, management information systems (MIS) are introduced that collect, process, and analyze relevant data. However, a precondition for the application of MIS is that users trust them. Extending accounts of trust in automation and trust in technology, we introduce a new model of trust in MIS that addresses the conceptual ambiguities of existing conceptualizations of trust and integrates initial empirical work in this field. In doing so, we differentiate between perceived trustworthiness of an MIS, experienced trust in an MIS, intentions to use an MIS, and actual use of an MIS. Moreover, we consider users’ perceived risks and contextual factors (e. g., autonomy at work) as moderators. The introduced model offers guidelines for future research and initial suggestions to foster trust-based MIS use.

Effects of exogenous lipids and cold acclimation on lycopene production and fatty acid composition in Blakeslea trispora

Exogenous lipids serving as stimulators to improve lycopene production in Blakeslea trispora have been widely reported. However, the selection basis of exogenous lipids and their effects on intracellular lipids are not very clear. In this study, five plant oils with different fatty acid compositions were selected to investigate their effects on lycopene production, fatty acid composition and the desaturation degree of intracellular lipids. Among the oils, soybean oil, with a fatty acid composition similar to that of mycelium, exhibited the best stimulating effect on lycopene formation (improvement of 82.1%). The plant oils enhanced the total content of intracellular lipids and the desaturation degree of reserve lipids due to the alteration of fatty acid composition, especially in neutral lipids. Lycopene production was increased with the improved desaturation degree of intracellular lipids, which may be attributed to the enhancement of storage capacity for lycopene in storage lipid, thus reducing the feedback regulation of free lycopene. In addition, the increase of the desaturation degree of reserve lipids through temperature-changing fermentation also enhanced lycopene production. The present study could serve as a basis for a better understanding of the relationship between the fatty acid composition of reserve lipids and lycopene production.

Supercritical CO2 and CH4 Uptake by Illite-Smectite Clay Minerals.

Clay minerals abound in sedimentary formations and the interaction of reservoir gases with their submicron features have direct relevance to many geoenergy applications. The quantification of gas uptake over a broad range of pressures is key toward assessing the significance of these physical interactions on enhancing storage capacity and gas recovery. We report a systematic investigation of the sorption properties of three source clay minerals-Na-rich montmorillonite (SWy-2), illite-smectite mixed layer (ISCz-1), and illite (IMt-2)-using CO2 and CH4 up to 30 MPa at 25-115 °C. The textural characterization of the clays by gas physisorption indicates that micropores are only partly accessible to N2 (77 K) and Ar (87 K), while larger uptakes are measured with CO2 (273 K) in the presence of illite. The supercritical excess sorption experiments confirm these findings while revealing differences in uptake capacities that originate from the clay-specific pore size distribution. The lattice density functional theory model describes accurately the measured sorption isotherms by using a distribution of properly weighted slit pores and clay-specific solid-fluid interaction energies, which agree with isosteric heats of adsorption obtained experimentally. The model indicates that the maximum degree of pore occupancy is universal to the three clays and the two gases, and it depends solely on temperature, reaching values near unity at the critical temperature. These observations greatly support the model's predictive capability for estimating gas adsorption on clay-bearing rocks and sediments.

Tailoring Storage Capacity and Ion Kinetics in Ti2CO2/ Graphene Heterostructures by Functionalization of Graphene

Two-dimensional (2D) materials) offer great potential for battery applications, due to their large surface areas, ability to accommodate various ions and molecules between their layers, and open channels for ion transport. The authors demonstrate that heterostructures made of an $M\phantom{\rule{0}{0ex}}X$ene and functionalized graphene are promising candidates to control and manipulate the generation and diffusion of Li${}^{+}$ at the interface of the dissimilar materials. Combining doped graphene with an $M\phantom{\rule{0}{0ex}}X$ene enhances storage capacity and markedly limits the volume change that is critical for eliminating restacking and maintaining cyclic stability.

Preparation and characterization of molybdenum tailings-based water storage material

In the current study, the possibility of incorporating molybdenum tailings into water storage materials was investigated. A new kind of water storage material was successfully prepared using molybdenum tailings as main raw material through foam molding and sintering. The water absorption, bulk density, compressive strength and water holding capacities of molybdenum tailings based water storage material (MTWSM) were tested. Crystal phase composition and microstructure of MTWSM were characterized by X-ray diffraction and field emission scanning electron microscopy. The results show that the optimum firing temperature of the sample is 1050 °C, and the relative parameters are as follows: water absorption rate 50.34%; bulk density 0.67 g cm−3; compressive strength 1.0 Mpa and water holding capacity 72.16%. Sintered samples all contain quartz as major phase, anorthite and micro-plagioclase as minor phase, and hematite as trace phase. MTWSM exhibits a rough and loose porous structure which is beneficial for water storage capacity enhancement. In this study, an environmentally friendly, economical and promising approach for full utilization of molybdenum tailings was developed.

Enhancement of storage capacity of CO2 in megaporous saline aquifers using nanoparticle-stabilized CO2 foam

Carbon dioxide sequestration in saline aquifers is a promising approach to reduce anthropogenic CO2 emissions and mitigate global climate change. CO2 storage capacity in aquifers depends on various factors such as interfacial tension, injection rate, viscosity ratio and characteristics of the porous media. We investigate the effects of these variables on CO2 gas and foam injection into a brine-saturated porous medium using a glass fabricated microfluidic device. The pore network is a representation of Washita-Fredericksburg formation located at a depth of 1110 m that is part of a saline aquifer located in southeast US and is currently under investigation to estimate its storage capacity as a commercial-scale CO2 storage hub. Contact angles and interfacial tensions between different fluids are measured under the experimental conditions. The three different injection rates are studied for each gaseous and foam injection. The displacement patterns images are captured by a high-resolution camera with an achromatic 60 M P sensor, and displacement performances are analyzed. CO2 foam injection appears to significantly increase CO2 storage in the microfluidic device (20%–40% higher compared to gas injection). Thus, CO2 foam injection is a promising approach to reduce CO2 mobility and enhance storage capacity in the target formation.

Microwave-power-enabled tuning of NiCo double hydroxide nanostructures

Microwave heating has been widely used to enhance the fabricating rate of nanomaterials in the past few decades. However, the application of interaction between microwave and chemical reaction in tuning nanomaterials morphology is yet to be explored, while strategies to manipulate material nanostructures are of great importance for enhanced function. In this work, we demonstrate the potential of microwave in tuning the morphology of nanostructured NiCo DHs by accurate temperature control through the precise design of microwave reacting system. We find that 200-W microwave irradiation gives yield to unique flower-on-sheet hierarchical structure of NiCo DHs, while microspheres are derived from oil-bath heating. Microwave power is found to play a vital role in the tuning process. When microwave power decreases to 50 W, assembled nanoflakes are obtained; when microwave power increases to 300 W, microspheres are obtained. Further, fluid permittivity is monitored and field intensity in the reacting region is simulated and found to increase with time. Taken together, it is proposed that field-induced de-solvation possibly exists and is the main tuning mechanism. When tested as electrode materials in supercapacitor, products obtained from 200 W microwave treatment show enhanced storage capacities, especially at high current density.

Phase and Morphology Evolution Induced Lithium Storage Capacity Enhancement of Porous CoO Nanowires Intertwined with Reduced Graphene Oxide Nanosheets

AbstractA simple and cost‐effective process is developed for the synthesis of a high‐performance anode consisting of porous CoO nanowires intertwined with reduced graphene oxide sheets (CoO−NWs/rGO). When tested in a lithium‐ion battery, the CoO−NWs/rGO exhibits high initial reversible capacity (∼960 mAh g−1) and excellent rate capability. More importantly, its performance is further enhanced when CoO−NWs/rGO is discharged/charged for >100 cycles. For example, the specific capacity of the CoO−NWs/rGO can reach up to 1195 mAh g−1 after ∼130 cycles. This enhancement of the electrochemical performance of the CoO−NWs/rGO is attributed to two effects during the repeated discharge/charge cycling: a gradual evolution in morphology and crystal structure of electrode materials and the transformation of CoO onto the surface of rGO sheets. While the initial porous structure and the wire‐shaped morphology of CoO NWs may help to alleviate the strains/stresses induced by the volume change associated with cycling, they do not seem to be the primary attributes to the observed performance enhancement. The implication of this finding is very important to the rational design of high‐performance electrode materials: the equilibrium structure and morphology of electrode materials under repeated cycling conditions are far more important than the initial structure and morphology in designing nanostructured electrodes with desired performance and durability.

Size-Tunable Natural Mineral-Molybdenite for Lithium-Ion Batteries Toward: Enhanced Storage Capacity and Quicken Ions Transferring.

Restricted by the dissatisfied capacity of traditional materials, lithium-ion batteries (LIBs) still suffer from the low energy-density. The pursuing of natural electrode resources with high lithium-storage capability has triggered a plenty of activities. Through the hydro-refining process of raw molybdenite ore, containing crushing–grinding, flotation, exfoliation, and gradient centrifugation, 2D molybdenum disulfide (MoS2) with high purity is massively obtained. The effective tailoring process further induce various sizes (5, 2, 1 and 90 nm) of sheets, accompanying with the increasing of active sites and defects. Utilized as LIB anodes, size-tuning could serve crucial roles on the electrochemical properties. Among them, MoS2-1 μm delivers an initial charge capacity of 904 mAh g−1, reaching up to 1,337 mAh g−1 over 125 loops at 0.1 A g−1. Even at 5.0 A g−1, a considerable capacity of 682 mAh g−1 is remained. Detailedly analyzing kinetic origins reveals that size-controlling would bring about lowered charge transfer resistance and quicken ions diffusion. The work is anticipated to shed light on the effect of different MoS2 sheet sizes on Li-capacity ability and provides a promising strategy for the commercial-scale production of natural mineral as high-capacity anodes.

Origin of storage capacity enhancement by replacing univalent ion with multivalent ion for energy storage

The storage capacity or capacitance of a material could be enhanced significantly by replacing univalent ion with multivalent ion in the energy storage field. However, the mechanism of the enhancement is unknown. Here, we dedicate to understand the origin of the enhancement on the storage capacity of multivalent ions over univalent ions. The experimental results show that the specific capacitance and charge-discharge rate of α-MnO2 are doubled by using Ca2+ cation to replace Na+ cation in the electrolyte as the energy storage medium. The First-principles calculations are used for a further understanding for the enhancement on the capacity, charge rate and the insertion mechanism. The given number of cations (two Na+ or Ca2+ ions) can be preferably stabled in one α-MnO2 unit cell to decrease the irreversible tetragonal-orthorhombic deformation caused by John-Teller effect. Because the insertion of Ca2+ triggers double electron transfer than Na+, the capacity and charge-discharge rate of α-MnO2 using Ca2+ cation as storage medium are doubled. The result pave a path to understand the enhancement on the storage capacity by replacing the univalent ions (such as Li+, Na+, K+, etc.) with multivalent ions (such as Ca2+, Mg2+, Zn2+, Al3+, etc.).

Enhanced Storage Capacity and Quality of Haleji and Hadero Lakes Connecting with Indus River for their Sustainable Revival

Enhanced Storage Capacity and Quality of Haleji and Hadero Lakes Connecting with Indus River for their Sustainable Revival

(Invited) Rational Design of Nanostructures and Materials for Flexible and High Performance Electronics and Optoelectronics

Wearable and flexible electronics requires energy efficient materials and devices with excellent flexibility for the active and passive components. Many nanostructured materials possess high surface-to-volume ratio, mechanical flexibility and low power consumption. These intriguing properties can be harnessed for a variety of applications in electronics and photonics. In the past, we have fabricated an assortment of arrayed nanostructures using a variety of materials from inorganic semiconductors to organometal perovskite materials. These nanomaterials can be fabricated with chemical vapor deposition method and/or printable method with scalability. Meanwhile, the materials have been fabricated into various flexible optoelectronic devices, including photodetectors and solar cells. The study has shown that three-dimensionally (3-D) arrayed nanostructures can help to improve solar cell device energy conversion efficiency, as well as the flexibility. However, rational design and proper structural optimization is not trivial. Using printable method and template guided growth method, semiconductor nanowires have been fabricated into planar arrays and 3-D arrays for photodetectors. Proof-of-concept flexible image sensor devices with high density 3-D nanowire arrays have been fabricated. Meanwhile, flexible energy storage devices have also been fabricated using nanostructured materials to enhance storage capacity for wearable devices. Overall, the nanostructure integration methodology that we developed may enable many applications on electronics and optoelectronics in the future.

Self-assembled SnO2/reduced graphene oxide nanocomposites via Langmuir-Blodgett technique as anode materials for Li-ion batteries

In the present work, we prepared tin oxide/reduced graphene oxide (SnO2/RGO) nanocomposites by a Langmuir-Blodgett (LB) technique. Few layers of graphene oxide have been transferred on to a copper foil in which SnO2 nanoparticles were deposited at the air-water interface. The prepared nanocomposites were used as anode materials for lithium-ion batteries and their energy storage capacities were examined in the absence of a binder in a run through. The SnO2/RGO-1 nanocomposite exhibited remarkable discharge capacity of 1091 mAhg−1 at the first cycle and its columbic efficiency retained to 62.5% after 20 cycles. The enhanced storage capacity and cyclic stability with ordered layer architecture ensure the prominence of classical LB method among the electrode contriving techniques used in energy storage devices.

Hybrid biopolymer electrodes for lithium- and sodium-ion batteries in organic electrolytes

Hybrid biopolymers, composed of lignin and PEDOT, show enhanced storage capacity for lithium- and sodium-ion batteries.

Carbon-rich shungite as a natural resource for efficient Li-ion battery electrodes

A wide variety of synthetic carbon allotropes embrace tremendous potential for energy storage applications. There have been number of reports on the synthesis of carbonaceous anode materials with lithium (Li) storage capacity larger than the theoretical limit for graphite (372 mAh/g, corresponding to LiC6). However, besides the performance, available resources and cost efficiency are obstacles that could hinder their exploitation. Here we present carbon-rich Precambrian rock “shungite” as a natural resource for a Li-ion battery anode. It is found that upon structural modification the energy density of fully lithiated “shungite” can exceed the density of graphite, becoming comparable to non-graphitizable (“hard”) carbon. High-resolution transmission electron microscopy (HRTEM) studies of modified “shungite” suggest that it consist of spatially arranged fractals of bended, curved, mono- or stacked graphene layers. By analyzing the features of 7Li Nuclear Magnetic Resonance (NMR) spectra of fully lithiated “shungite” we conclude that the enhanced storage capacity is mainly due to the presence of open edge few layered graphene flakes. We thus suggest carbon-rich “shungite” as an alternative and effective natural resource for Li-ion battery electrodes.

Composite “LiCl/MWCNT” as advanced water sorbent for thermal energy storage: Sorption dynamics

Sorption heat storage (SHS) is a promising technology towards efficient use of renewable energy sources. Composite materials based on hygroscopic salts have a high potential for SHS in term of the heat storage capacity. Recently, a new sorbent “LiCl confined to Multi-Wall Carbon NanoTubes (MWCNT)” with enhanced storage capacity (1.7kJ/g) has been suggested for SHS. This work addresses the dynamic study of water sorption on this material under operating conditions of a daily heat storage cycle. The study consists of three parts: (1) shaping the LiCl/MWCNT composite as grains (GP) and pellets with (PB) and without a binder (PP); (2) water sorption dynamics under conditions of the selected SHS cycle; (3) evaluation of the specific power achievable. Various configurations of the adsorbent bed were tested, namely, the loose grains GP placed on a metal support, and the pellets PB and PP glued to the support. The dynamic curves of water sorption obey an exponential equation. The PB configuration ensured a maximal specific power of 11.2kW/kg (at 70% conversion) during the heat storage stage. During the heat release stage, the specific power is lower (5.4kW/kg), probably due to a kinetic hindrance attributed to solid-solid transformation during the decomposition of LiCl·H2O complex towards the anhydrous salt. The high specific power along with the large heat storage capacity make the LiCl/MWCNT composite a promising new candidate for SHS.

A one-step in-situ assembly strategy to construct PEG@MOG-100-Fe shape-stabilized composite phase change material with enhanced storage capacity for thermal energy storage

A novel in-situ assembly strategy has been developed to synthesis polyethylene glycol (PEG)@iron-benzenetricarboxylate metal-organic gel (MOG-100-Fe) shape-stabilized composite phase change materials by regulating metal-to-ligand ratio. The PEG@MOG-100-Fe was prepared by an ingenious introduction of PEG into the traditional sol-gel prepared MOG-100-Fe. The composite exhibited high heat storage density and thermal stability. The PEG loading content reached up to 92% without any leakage above its melting point. The heat storage density reaches to 152.88 kJ kg−1 and is up to 95.8% of their theoretical value. These novel composite PCMs also exhibited excellent recyclability after 50 thermal cycles.