The funnel effect and its practical benefits in wind applications

Capatina, O.; Groşan, Teodor; Vadan, Ioan; Trîmbiţaş, Radu T.; Ignat, S.; Calarasu, A.

doi:10.1109/aqtr.2010.5520784

Cited by 1 publication

(2 citation statements)

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“…Other research has shown that a funnel‐like structure can be used to improve fluid speed. [ 51 ] β‐CD shows a truncated cone structure as shown in Figure 4a,b and therefore is expected to cause a “funnel effect” to promote lithium‐ion transport. According to Equation (), the fluid speed at the β‐CD funnel entrance ( V es ) is 69% higher than that at the exiting end of β‐CD ( V in ).

V_{es =} V_{in} \cdot \frac{A}{a} = V_{in} \cdot {()(, \frac{D}{d})}^{2}

where V in represents the speed at the funnel entrance (area A , diameter D ), and V es is the speed at the exiting end of the funnel (area a , diameter d ).…”

Section: Resultsmentioning

confidence: 99%

“…Other research has shown that a funnel-like structure can be used to improve fluid speed. [51] β-CD shows a truncated cone structure as shown in Figure 4a,b and therefore is expected to cause a "funnel effect" to promote lithium-ion transport. According to Equation (1), the fluid speed at the β-CD funnel entrance (V es ) is 69% higher than that at the exiting end of β-CD (V in ).…”

Section: Resultsmentioning

confidence: 99%

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Microporous Cyclodextrin Film with Funnel‐type Channel Polymerized on Electrospun Cellulose Acetate Membrane as Separators for Strong Trapping Polysulfides and Boosting Charging in Lithium–Sulfur Batteries

Shi

Nie

et al. 2022

Energy & Environ Materials

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Lithium-ion secondary batteries (LIB) have been deemed less favorable devices for portable electronic devices and electric vehicles due to their safety issues, high cost, and low theoretical energy density. [1][2][3] Compared to LIB, Li-S battery has superior theoretical specific capacity of 1675 mAh g −1 and good theoretical energy density of 2600 Wh kg −1 . [4,5] Li-S battery is thus considered one of the most promising candidates for next-generation highenergy density batteries. [6,7] However, the intrinsic limitations of Li-S batteries severely impede their commercial development. [7,8] Firstly, the inherent insulating nature of sulfur and insoluble Li 2 S leads to poor electrochemical kinetics, low utilization of active sulfur, and inferior coulomb efficiency. [9][10][11] Secondly, the soluble long-chain polysulfides may be dissolved in organic electrolyte, resulting in severe "shuttle effect" to cause rapid capacity decay and poor cycling performance. [12][13][14] Finally, the notorious "shuttle effect" could corrode lithium anode, exacerbating the growth and uneven deposition of lithium dendrites, severely affecting the rate performance and safety in use of Li-S battery. [15,16] Massive efforts have been taken to overcome these drawbacks of Li-S batteries. [17,18] For example, the insulating nature of sulfur can be addressed by hosting the sulfur in highly conductive graphene and carbon nanotubes frameworks. [19,20] Within the Li-S battery configuration, separator is used to prevent the direct contact between the cathode and anode, and dominates the key battery performances such as internal resistance, capacity, cycle property, and safety. [21] At present, commercial polyolefin (polypropylene and polyethylene) separators are generally used in Li-S batteries. However, these separators would bring about serious polysulfides "shuttle effect" due to the low porosity, poor electrolyte affinity, and inferior thermal stability, causing active sulfur substance loss, rapid capacity decay, and other issues. [22,23] Due to the high porosity, large specific surface area, and chemical stability, electrospun nanofiber membranes have been proved to be more effective as separators for Li-S batteries. [23,24] In addition, the strong affinity between the electrospun nanofiber membrane and electrolyte can significantly enhance the lithium-ion migration. [25,26] Electrospun cellulose acetate membrane has been used as separator in LIB due to its polar nature and strong affinity to electrolyte. [27] Electrospun nanofiber membranes containing oxygen-rich polar groups have been employed as Li-S battery separators to effectively inhibit "shuttle effect," owing to the strong binding energy between the oxygen and polysulfides. [28,29] Other than chemical adsorption of

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V_{es =} V_{in} \cdot \frac{A}{a} = V_{in} \cdot {()(, \frac{D}{d})}^{2}

where V in represents the speed at the funnel entrance (area A , diameter D ), and V es is the speed at the exiting end of the funnel (area a , diameter d ).…”