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In order to solve the problem of high energy consumption caused by node overload in complex network flow, a simulation load separation control algorithm based on complex network flow is proposed. According to the characteristics of complex network flow, combined with the characteristics of traffic in the network, a tree combined classifier is designed to discretize the complex network, analyze the micro dynamics of nodes in the network, and simulate the load division of nodes in complex network flow by dividing simulation load, evaluating node bandwidth, transferring overload nodes, and controlling the tree combined classifier. The experimental results show that the designed discrete control algorithm has the advantages of low cost, good load balancing, low energy consumption, and good simulation load discrete control performance. [ABSTRACT FROM AUTHOR]

Rechargeable aqueous zinc‐based flow batteries (ZFBs) are promising candidates for large scale energy storage devices. However, the challenges from zinc dendrites and limited areal capacity considerably impede their wide application. Here, an in situ vertical growth of layered double hydroxide membrane (LDH‐G) is constructed to enable long‐life ZFBs. Owing to the high hydroxide ion conductivity and ion selectivity nature of LDH nanosheets, specifically, the precise control of directional ion transport in vertical arrangement LDHs, a superior battery performance can be realized. Moreover, the defect‐free LDHs layer serves as a buffer layer to enable a uniform Zn deposition, which effectively enhances the areal capacity of the battery. As a result, the designed membrane endows an alkaline zinc‐iron flow battery with excellent rate performance and cycling stability, maintaining an energy efficiency of 80% at 260 mA cm−2 for 800 cycles, which is the highest performance ever reported. Most importantly, the LDHs layer enables the battery for 1200 h long‐cycle stability with a uniform Zn deposition and high areal capacity of 240 mAh cm−2. This work realizes an in situ growth of 3D LDHs arrays on the polymer substrate, which provides a strategy toward high areal capacity and dendrite‐free Zn deposition for ZFBs. [ABSTRACT FROM AUTHOR]

The capability to maintain a constant system temperature is vital in nature, since it endows the system with enhanced lifetime. This trait also works for zinc‐based batteries, because their cycle‐life is limited by notorious zinc dendrite/accumulation, which are highly affected by the inhomogeneous distribution of temperature on electrode and relatively low mechanical strength of membrane. Herein, boron nitride nanosheets (BNNSs) with high mechanical strength serving as heat‐porter are introduced onto a porous substrate to enable uniform deposition of zinc and further a zinc‐based flow battery with long‐cycle life. The results indicate that BNNSs can effectively adjust the deposited zinc from needle‐like to French fries‐like morphology, thus affording the battery with a stable performance for nearly 500 cycles at 80 mA cm−2. Most importantly, an energy efficiency of above 80 % can be obtained even at 200 mA cm−2, which is by far the highest value ever reported among zinc‐based flow batteries. [ABSTRACT FROM AUTHOR]

A membrane with both high ion conductivity and selectivity is critical to high power density and low-cost flow batteries, which are of great importance for the wide application of renewable energies. The trade-off between ion selectivity and conductivity is a bottleneck of ion conductive membranes. In this paper, a thin-film composite membrane with ultrathin polyamide selective layer is found to break the trade-off between ion selectivity and conductivity, and dramatically improve the power density of a flow battery. As a result, a vanadium flow battery with a thin-film composite membrane achieves energy efficiency higher than 80% at a current density of 260 mA cm−2, which is the highest ever reported to the best of our knowledge. Combining experiments and theoretical calculation, we propose that the high performance is attributed to the proton transfer via Grotthuss mechanism and Vehicle mechanism in sub-1 nm pores of the ultrathin polyamide selective layer. Low-cost flow batteries with high power density are promising for energy storage, but membranes with simultaneously high ion conductivity and selectivity should be developed. Here the authors report a thin-film composite membrane that breaks the trade-off between ion conductivity and selectivity. [ABSTRACT FROM AUTHOR]

Abstract: A zinc–iodine flow battery (ZIFB) with long cycle life, high energy, high power density, and self‐healing behavior is prepared. The long cycle life was achieved by employing a low‐cost porous polyolefin membrane and stable electrolytes. The pores in the membrane can be filled with a solution containing I3− that can react with zinc dendrite. Therefore, by consuming zinc dendrite, the battery can self‐recover from micro‐short‐circuiting resulting from overcharging. By using KI, ZnBr2, and KCl as electrolytes and a high ion‐conductivity porous membrane, a very high power density can be achieved. As a result, a ZIFB exhibits an energy efficiency (EE) of 82 % at 80 mA cm−2, which is 8 times higher than the currently reported ZIFBs. Furthermore, a stack with an output of 700 W was assembled and continuously run for more than 300 cycles. We believe this ZIFB can lead the way to development of new‐generation, high‐performance flow batteries. [ABSTRACT FROM AUTHOR]

UI rendering on smartphones needs powerful CPU and GPU to meet user-perceived smoothness, and it contributes a significant portion of energy consumption of the battery-driven device. Improving energy efficiency of rendering process without degrading user experience has attracted research attention in both academia and industry. In this work, we propose an energy-efficient rendering optimization framework, called HB-ReTriple, based on reusing the rendering results of the unchanged Views across adjacent frames. This reusing can effectively reduce the amount of computation spent on UI rendering, thereby saving considerable energy. We implement our framework on a real Android mobile platform, and the experiments show that HB-ReTriple achieves an average speedup of 2.89x in terms of frames-per-second (FPS) and an energy saving of 38.2% per-frame. [ABSTRACT FROM AUTHOR]

Packet classification is implemented in modern network routers for providing differentiated services based on packet header information. Traditional packet classification only reports a single matched rule with the highest priority for an incoming packet and takes an action accordingly. With the emergence of new Internet applications such as network intrusion detection system, all matched rules need to be reported. This multi-match problem is more challenging and is attracting attentions in recent years. Because of the stringent time budget on classification, architectural solutions using ternary content addressable memory (TCAM) are the preferred choice for backbone network routers. However, despite its advantage on search speed, TCAM is much more expensive than SRAM, and is notorious for its extraordinarily high power consumption. These problems limit the application and scalability of TCAM-based solutions. This paper presents a tree-based multi-match packet classification technique combining the benefits of both TCAMs and SRAMs. The experiments show that the proposed solution achieves significantly more savings on both memory space and power consumption on packet matching compared to existing solutions. [ABSTRACT FROM AUTHOR]

Abstract Solvent treatment has been proved to be a very simple and effective method to prepare high-performance porous membranes for flow batteries. However, the initial morphology and the properties of membrane materials will exert pivotal effects on the resultant performance of porous membranes. In this paper, according to comparing the differences in the morphology and performance of untreated and treated porous poly(ether sulfone) (PES) membranes with different porous structures, the influence of the initial morphology of membranes was clarified in detail. Moreover, the differences in the morphology and performance of untreated and treated porous poly(vinylidene fluoride) (PVDF), polusulfone (PSF) and poly (vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) membranes were also investigated. By comparing various properties of PES, PVDF, PSF and PVDF-HFP polymers, the importance and criteria for selecting proper membrane materials when using the solvent treatment method were clarified. Furthermore, the VFB assembled with the resultant membrane could achieve an energy efficiency of 82.93% at 80 mA cm−2, which could be comparable to that of the commercial Nafion 115. Therefore, this article is beneficial for designing high-performance porous membranes for flow batteries. Graphical abstract fx1 Highlights • The membrane formation mechanism was investigated for flow battery application. • The membrane morphology was tuned by solvent treatment. • The factors of initial morphology and polymer properties were studied in detail. • A controlled performance can be achieved by changing preparation parameters. [ABSTRACT FROM AUTHOR]

Abstract: Performance evaluation method is very important for the research on flow batteries. Charging–discharging test is the most typical evaluation method for flow batteries. Recently, the polarization curves, together with the associated power density curves, which are commonly employed in fuel cells, have come into use for flow batteries' performance evaluation. Based on the investigation of performance evaluation method, it is confirmed charging–discharging test is optimal for flow batteries' performance evaluation. A comparison of voltage losses (voltage efficiency, VE) can be clearly delivered from the polarization curves, which are quite practical for fuel cells' performance evaluation. While for flow batteries, apart from VE, coulombic efficiency (CE), energy efficiency (EE), utilization of electrolyte (UE) and capacity stability should be seriously considered during charging–discharging process. However, CE and UE are inaccessible; accordingly EE and capacity stability can't be detected from polarization curves. Therefore, the polarization curve is improper to serve as a performance evaluation method for flow batteries. On the premise of a proper CE, a rough performance evaluation for flow batteries can be achieved via the polarization curves. The peak power density is of limited significance in practical use due to the extremely low EE obtained at that point. [Copyright &y& Elsevier]

Three-Level pore structure with ultrahigh transport enhances the salt-resistant, antifouling performance and reduces the water evaporation enthalpy and increases the water evaporation rate of the hydrogel. [Display omitted] • Three-level pore structure hydrogels (TLPSHs) were prepared by PVA and rGO. • The micro-environment was proposed to explain the decrease of evaporation enthalpy. • The TLPSHs with 88 % porosity has more than 97 % sunlight absorption. • The TLPSHs shown a stable evaporation rate of 1.65 kg m-2h −1. Photothermal evaporation materials have drawn attention owing to their high solar energy utilization. In this work, a series of three-level pore structure hydrogels (TLPSHs) consisting of polyvinyl alcohol (PVA), graphene oxide (GO) or reduced graphene oxide (rGO) are prepared. The hydrogel with PVA crosslinked with rGO shows the most promising properties mainly owing to its three-level pore structure being a combination of nanosized pores for low enthalpy water evaporation and a broad distribution of micronsized pores facilitating water transport into said nanosized pores. When varying the content of rGO/PVA between 5 and 15 wt%, the 10 wt% loading gives the highest water evaporation rate and energy conversion efficient owing to its microstructure combining intra water hydrogen disruption and water transport. The TLPSHs with 88 % porosity has more than 97 % sunlight absorption throughout the UV–Vis-NIR spectrum and stable evaporation rate (1.65 kg m-2h−1) under 1 sun irradiation. The hydrogel rejects salt by having a higher temperature than the surrounding seawater which causes salt to precipitate in the water rather than on the hydrogel evaporator when the saturation limit is reached. Lastly, the scalability and real life applicability is demonstrated through outdoor experiments on seawater. [ABSTRACT FROM AUTHOR]

Abstract: A novel single flow zinc–bromine battery is designed and fabricated to improve the energy density of currently used zinc–bromine flow battery. In the assembled battery, liquid storage tank and pump of positive side are avoided and semi solid positive electrode is used for improving energy efficiency and inhibiting bromine diffusion into environment. The single flow battery with this design shows columbic efficiency (CE) of 92% and energy efficiency (EE) of 82% over 70 cycles at the current density of 20 mA cm−2, which is comparable with the performance of the traditional zinc–bromine flow battery; furthermore, it has much lower weight and bromine emission. [Copyright &y& Elsevier]

Abstract: Crosslinkable sulfonated poly (diallyl-bisphenol ether ether ketone) (SDPEEK) membranes with different degrees of sulfonation (DS) are prepared and first investigated in vanadium redox flow battery (VFB) application. The SDPEEK membranes with DS of 80% (SD4-6-100) show over an order of magnitude lower permeability of VO2+ ions (2.4 × 10−8 vs. 1.04 × 10−6 cm2 min−1) than currently used Nafion 115. The VFB battery assembled with SD4-6-100 membrane exhibits much higher columbic efficiency (98% vs. 92% at 50 mA cm−2) and longer self-discharge time (180 h vs. 50 h) than that of Nafion 115, however, at similar energy efficiency. The membrane keeps a stable performance after 900 h charge–discharge test. In order to further improve the ions selectivity of SDPEEK membranes with high DS, the SD5-5-50 (DS 100%) membrane is crosslinked under ultraviolet (UV) radiation. The ion selectivity of the membrane is improved obviously after crosslinking, as a result, showing much higher columbic efficiency and energy efficiency. [Copyright &y& Elsevier]

Abstract: Poly(tetrafluoroethylene) reinforced sulfonated poly(ether ether ketone) (SPEEK/PTFE) composite membranes are prepared for vanadium redox flow battery (VRB) application. Results show that SPEEK/PTFE composite membranes have lower water uptake and swelling ratio than that of SPEEK membranes due to the PTFE reinforcement. As a result, the composite membranes show higher elongation ratio and better mechanical stability than SPEEK membranes. VRB single cell tests are also carried out to further evaluate their performance. The batteries assembled with SPEEK/PTFE membranes exhibit higher columbic efficiency (CE) and energy efficiency (EE) than that of SPEEK membranes. Furthermore, the composite membranes show much better stability than pristine SPEEK, confirming that PTFE can effectively reinforce membranes to improve their chemical and mechanical stability under VRB operating condition. [Copyright &y& Elsevier]

The recently proposed high power density zinc–nickel single flow batteries (ZNBs) exhibit great potential for larger scale energy storage. The urgent needs are in the research into temperature adaptability of ZNBs before practical utilization. Furthermore, making clear their polarization distribution is essential to direct the further improvement of battery performance. Here, we focus on the trends in the polarization distribution and effect of temperature on the performance of ZNBs. The result shows that ZNBs can operate in the temperature range from 0 °C to 40 °C with acceptable energy efficiency (53%–79.1%) at 80 mA cm−2. The temperature sensitivity of coulombic efficiency and energy efficiency are 0.65% °C−1 and 0.98% °C−1 at 0 °C–20 °C, respectively. The positive polarization is much larger than the negative polarization at all studied temperatures. The charge overpotential of the positive electrode is more sensitive to temperature. These results enable us to better evaluate the application prospect of ZNBs and point a clear struggling orientation to further improve the battery performance. [ABSTRACT FROM AUTHOR]

Abstract: A novel carbon paper electrode coated with supported tungsten trioxide is developed to improve the carbon fiber’s electrochemical performance toward the vanadium redox couples. Super activated carbon supported tungsten trioxide (WO3/SAC) is prepared via an impregnation method and characterized by X-ray diffraction and scanning electron microscopy. The electrochemical performance of the prepared electrode is evaluated with cyclic voltammetry and electrochemical impedance spectroscopy. Results show that WO3/SAC exhibits excellent electro-catalytic activity and kinetic reversibility toward the vanadium redox couples. By adding the WO3/SAC, the charge transfer resistances for both the positive and the negative reactions are significantly reduced. Using as prepared electrodes, the columbic efficiency (CE), voltage efficiency (VE) and energy efficiency (EE) of the vanadium redox flow battery at 50 mA cm−2 are 94.5%, 85.2% and 80.5%, respectively, which are much higher than that of the cell assembled with pristine carbon paper electrodes. [Copyright &y& Elsevier]

Alkaline zinc-iron flow battery (AZIFB) is emerged as one of the cost-effective technologies for electrochemical energy storage application. A cost-effective ion-conducting membrane with high performance is very important for the battery. In this paper, a cost-effective non-ionic poly (ether sulfone) (PES) membrane with high ion conductivity and high anti-alkali stability is designed for AZIFB. The non-ionic membrane is constructed by using PES as the matrix, while a bifunctional polyethylene glycol (PEG) is employed as additive. The PEG can on the one hand conduct charge-balancing ions through the alkalized-ether functionality, while on the other hand, create nano-scale pores in the matrix by partially dissolving in water. Thus, the battery with an optimized membrane exhibits a coulombic efficiency (CE) as high as 99.26% and an energy efficiency (EE) of 86.81% at a current density of 80 mA cm-2. Moreover, after soaking the non-ionic membrane in 6 mol L-1 NaOH at 50 °C for 8 days, the battery operating at 80 mA cm-2 can still steadily run for 120 cycles, demonstrating high anti-alkali stability. The above results suggest that the non-ionic membranes present very promising prospects for AZIFB. Image 1 • A non-ionic membrane is designed for alkaline zinc-iron flow battery. • The transfer of ions is realized via a bifunctional polyethylene glycol. • The designed membrane demonstrates excellent stability in alkaline media. • The battery with the membrane shows a CE of ~99% and an EE of ~87% at 80 mA cm-2. [ABSTRACT FROM AUTHOR]

A zeolite composite membrane (ZCM) was designed and fabricated via a simple versatile and scalable method. A thin layer of ZSM-35 flakes with pore size between hydrated protons and vanadium ions was fixed on the poly(ether-sulfone)/sulfonated poly(ether-ether-ketone) (PES/SPEEK) porous substrate by in-situ interfacial polymerization. The ZSM flake layer can perfectly separate hydrated vanadium ions and protons, therefore, show very impressive performance for vanadium flow batteries (VFBs). As a result, a VFB assembled with an optimized ZCM exhibited a columbic efficiency more than 99% and energy efficiency of over 91% at a current density of 80 mA cm-2, which is among the highest performance ever reported. Furthermore, the energy efficiency can reach 81.6% at a very high current density of 200 mA cm-2 and keep stable for 1000 cycles at a current density of 180 mA cm-2. This method opened a door toward the large-scale production of highly selective composite membranes for flow batteries. Image 1 • A novel and scalable method was developed to fabricate advanced composite membrane. • Ions were precisely selected by zeolite functional layer with uniform pore size. • In-situ interfacial polymerization fixed the zeolite well on the substrate. • A Vanadium flow battery with this membrane demonstrated one of the highest performance. [ABSTRACT FROM AUTHOR]