Copolymer-assisted Polypropylene Separator for Fast and Uniform Lithium Ion Transport in Lithium-ion Batteries

In lithium-ion batteries(LIBs),separators play a vital role in lithium-ion(Li+)transport,and thus affect rate performance,battery life,and safety.Here,a new kind of multifunctional copolymer poly(acrylonitrile-co-lithium acrylate-co-butyl acrylate)(PAAB-Li)is synthesized through soap-free emulsion polymerization,and is used to form homogeneous-covered separator based on PP matrix by a simple dip-annealing process.Compared to the bare PP separator,the modified separators with PAAB-Li enable higher ionic conductivity,higher lithium ion transference number(increased from 0.360 to 0.525),and lower interface impedance(reduced from 155Ω to 34Ω).It has been indicated that PAAB-Li functional layer significantly promotes the fast transport of Li+and improves the compatibility of the separator/electrolyte-electrode interface.The LiCo02/graphite cells with the PAAB-Li-assisted separator demonstrate excellent cycle stability and rate performance.In addition,the Li symmetric cells with the modified separator stably cycle over 800 h,indicating the functional layer effectively suppresses the lithium dendrite growth.This facile strategy can be easily applied to LIBs requiring high safety and even be scalable to Li metal batteries.Moreover,the possible mechanism of the PAAB-Li functional layer promoting fast and uniform Li+transport is discussed in this paper.

Non-dispersive solvent extraction ofp-toluic acid from purifiedterephthalic acid plant wastewater with p-xylene as extractant

Non-dispersive solvent extraction （NDSE） with p-xylene as extractant was employed as a novel separation methodto recover both ρ-toluic （PT） acid and water from purified terephthalic acid （PTA） wastewater. The mass transport behavior ofPT acid from aqueous solution to ρ-xylene was investigated by experiments and numerical simulation. Experiments showed thatNDSE is feasible and effective. Residual PT acid in the raffinate can be reduced to lower than the permitted limit of wastewaterre-use （100 g/m^3） with extraction time longer than 60 s in industrial conditions. A mathematical model of PT acid mass transportwas developed to optimize the membrane module performance. The model was validated with the experimental results withrelative errors of less than 6%. Numerical analysis for mass transfer through the lumen side, the porous membrane layer, and theshell side showed that PT acid transport in the aqueous solution is the rate determining step. The effects of the membrane andoperating parameters on membrane module performance were investigated by means of computational simulations. The keyparameters suggested for industrial NDSE design are： fiber inner radius r1=200-250 μm, extraction time tc=50-60 s, aqueous/organic volumetric ratio a/o=9.0, and temperature T-318 K.

中空纤维膜脱氧过程中Dean涡强化传质研究（英文）

目的:在螺旋中空纤维膜脱氧过程中引入了Dean涡,与线型中空纤维膜脱氧过程相比传质速率显著提升。本文旨在建立新的螺旋中空纤维膜脱氧过程传质模型,探讨管程流体雷诺数、中空纤维膜结构参数、壳程真空度和操作温度对Dean涡强化传质效果的影响,并优化螺旋中空纤维膜脱氧过程操作参数。创新点:1.建立新的螺旋中空纤维膜脱氧过程传质模型;2.该传质模型可以应用于任何螺旋中空纤维膜气-液过程的传质行为描述。方法:1.实验研究管程流体雷诺数、中空纤维膜结构参数、壳程真空度和操作温度对Dean涡强化传质效果的影响,并与线型中空纤维膜传质进行对比。2.利用螺旋坐标系下的质量连续性方程以及Dean涡的摄动解描述管程溶质的传质行为;利用改进的尘气模型描述膜孔道内多组份气体的扩散行为;耦合建立新的螺旋中空纤维膜脱氧过程传质模型,并与实验结果进行比较。3.模拟脱氧过程的氧、氮、水三种组分的浓度分布,优化螺旋中空纤维膜脱氧过程的膜结构参数和操作参数。结论:1.实验和模拟结果均证实Dean涡可以有效提升脱氧传质速率,最大传质增强因子为2.2。2. Dean涡主要受到管程雷诺数和中空纤维膜曲率的影响;当管程雷诺数较大时,中空纤维膜即使存在很小的曲率,传质的速率也有显著的提升。