Engineering Strategies for Suppressing the Shuttle Effect in Lithium–Sulfur Batteries

Lithium–sulfur(Li–S)batteries are supposed to be one of the most potential next-generation batteries owing to their high theoretical capacity and low cost.Nevertheless,the shuttle effect of firm multi-step two-electron reaction between sulfur and lithium in liquid electrolyte makes the capacity much smaller than the theoretical value.Many methods were proposed for inhibiting the shuttle effect of polysulfide,improving corresponding redox kinetics and enhancing the integral performance of Li–S batteries.Here,we will comprehensively and systematically summarize the strategies for inhibiting the shuttle effect from all components of Li–S batteries.First,the electrochemical principles/mechanism and origin of the shuttle effect are described in detail.Moreover,the efficient strategies,including boosting the sulfur conversion rate of sulfur,confining sulfur or lithium polysulfides(LPS)within cathode host,confining LPS in the shield layer,and preventing LPS from contacting the anode,will be discussed to suppress the shuttle effect.Then,recent advances in inhibition of shuttle effect in cathode,electrolyte,separator,and anode with the aforementioned strategies have been summarized to direct the further design of efficient materials for Li–S batteries.Finally,we present prospects for inhibition of the LPS shuttle and potential development directions in Li–S batteries.

Shuttle配流方案对轴向柱塞泵关键性能的研究

针对轴向柱塞泵配流过程中产生的节流损失、压力冲击等问题,创新设计基于Shuttle配流方案的柱塞泵模型,建立基于Shuttle配流方案的斜盘式轴向柱塞泵AMESim仿真模型。通过与原配流方案对比,验证了Shuttle配流方案中的无节流槽配流盘和可变容积缸体,可以使得柱塞腔在配流中实现更柔和的压缩和膨胀,压力超调更小,同时不存在配流节流损失。仿真结果与2022年INNAS公司公布了Shuttle技术的试验效果一致。

Tackling the proton limit under industrial electrochemical CO_(2)reduction by a local proton shuttle

Industrial CO_(2)electroreduction has received tremendous attentions for resolution of the current energy and environmental crisis,but its performance is greatly limited by mass transport at high current density.In this work,an ion‐polymer‐modified gas‐diffusion electrode is used to tackle this proton limit.It is found that gas diffusion electrode‐Nafion shows an impressive performance of 75.2%Faradaic efficiency in multicarbon products at an industrial current density of 1.16 A/cm^(2).Significantly,in‐depth electrochemical characterizations combined with in situ Raman have been used to determine the full workflow of protons,and it is found that HCO_(3)^(−)acts as a proton pool near the reaction environment,and HCO_(3)^(−)and H_(3)O^(+)are local proton donors that interact with the proton shuttle−SO_(3)^(−)from Nafion.With rich proton hopping sites that decrease the activation energy,a“Grotthuss”mechanism for proton transport in the above system has been identified rather than the“Vehicle”mechanism with a higher energy barrier.Therefore,this work could be very useful in terms of the achievement of industrial CO_(2)reduction fundamentally and practically.

VSe_(2)/V_(2)C heterocatalyst with built-in electric field for efficient lithium-sulfur batteries:Remedies polysulfide shuttle and conversion kinetics

Lithium sulfur(Li-S)battery is a kind of burgeoning energy storage system with high energy density.However,the electrolyte-soluble intermediate lithium polysulfides(Li PSs)undergo notorious shuttle effect,which seriously hinders the commercialization of Li-S batteries.Herein,a unique VSe_(2)/V_(2)C heterostructure with local built-in electric field was rationally engineered from V_(2)C parent via a facile thermal selenization process.It exquisitely synergizes the strong affinity of V_(2)C with the effective electrocatalytic activity of VSe_(2).More importantly,the local built-in electric field at the heterointerface can sufficiently promote the electron/ion transport ability and eventually boost the conversion kinetics of sulfur species.The Li-S battery equipped with VSe_(2)/V_(2)C-CNTs-PP separator achieved an outstanding initial specific capacity of 1439.1 m A h g^(-1)with a high capacity retention of 73%after 100 cycles at0.1 C.More impressively,a wonderful capacity of 571.6 mA h g^(-1)was effectively maintained after 600cycles at 2 C with a capacity decay rate of 0.07%.Even under a sulfur loading of 4.8 mg cm^(-2),areal capacity still can be up to 5.6 m A h cm^(-2).In-situ Raman tests explicitly illustrate the effectiveness of VSe_(2)/V_(2)C-CNTs modifier in restricting Li PSs shuttle.Combined with density functional theory calculations,the underlying mechanism of VSe_(2)/V_(2)C heterostructure for remedying Li PSs shuttling and conversion kinetics was deciphered.The strategy of constructing VSe_(2)/V_(2)C heterocatalyst in this work proposes a universal protocol to design metal selenide-based separator modifier for Li-S battery.Besides,it opens an efficient avenue for the separator engineering of Li-S batteries.

单重靶向条件复制型腺病毒穿梭载体pshuttle-E1A-E1Bp-E1B55K的构建及鉴定

目的:构建并鉴定一种新型E1A基因CR2区选择性缺失的腺病毒穿梭载体pshuttle-E1A-E1Bp-E1B55K,为包装单重靶向条件复制型腺病毒进行肿瘤基因治疗奠定基础。方法:采用RT-PCR法从人胚肾细胞(293T)中扩增条件复制型腺病毒必需的E1区基因,包括E1A、E1Bp及E1B55K基因片段;重叠PCR法扩增CR2区缺失的E1A基因;采用基因重组技术构建pshuttle-E1A-E1Bp-E1B55K重组质粒,并进行PCR及酶切鉴定。结果:经测序证实获得的E1B55K及CR2区缺失的E1A基因与GenBank公布的完全一致,E1A基因CR2区缺失的pshuttle-E1A-E1Bp-E1B55K质粒经分别经XbaⅠ与KpnⅠ单酶切,得到大小约为817和1244bp的酶切片段,PCR鉴定得到约250及1148bp的基因片段,鉴定结果与预期结果完全一致。结论:E1A基因CR2区选择性缺失的单重靶向条件复制型腺穿梭载体pshuttle-E1A-E1Bp-E1B55K构建成功。

锂离子电池过充保护添加剂shuttle的研究

通过在锂离子电池电解液中添加2,5-二叔丁基-1,4-二甲氧基苯(2,5-diterbutyl-1,4-dimethoxybenzene,简称shuttle)来提高电池的过充保护能力。对磷酸铁锂电池分别进行了循环伏安扫描、常温循环寿命、过充后循环、交流阻抗测试,实验结果表明,在1 mol/L LiPF6/(EC+DEC+EMC)(1∶1∶1)+1%VC电解液中添加2%(质量分数)shuttle,当电压为3.81 V(相对于Li/Li+)时,shuttle开始发生氧化反应,烷氧基发生氧化离解,消耗电池内部过充的电量,提高了锂离子电池的安全性。此外,添加2%(质量分数)shuttle后电池循环性能有所提高,循环180次后,容量保持率从91.60%提高至94.70%。

腺病毒穿梭质粒pShuttle CMV-^+VEGF_(121)-IRES-hrGFP-1的构建和鉴定

目的构建腺病毒穿梭质粒pShuttle CMV-^+VEGF_(121)-IRES-hrGFP-1,为构建表达具有抗原表位标记的血管内皮生长因子121(vascular endothelial growth factor 121,VEGF_(121)),并同时表达绿色荧光蛋白(green fluorescent protein,GFP)报告分子的腺病毒真核细胞表达载体打下基础。方法对目的基因供体质粒pTG19T-VEGF_(121)携带的VEGF_(121)基因测序和序列内部存在的限制性内切酶识别位点进行分析,利用PCR(Polymerase Chain Reaction,PCR)技术对pTG19T-VEGF_(121)携带的VEGF_(121)基因突变,以去除翻译终止密码子后的基因序列并在序列前后分别添加新的NotI和XhoI酶切位点。将突变后的VEGF_(121)基因(^+VEGF_(121))定向连入腺病毒穿梭质粒pShuttle CMV-IRES-hrGFP-1,通过电泳和测序鉴定获得的重组质粒。结果重组质粒经电泳和测序鉴定为正确克隆。结论成功构建了pShuttle CMV-^+VEGF_(121)-IRES-hrGFP-1。

腺病毒穿梭质粒pShuttleCMV-BMP2^+-IRES-hrGFP-1的构建和鉴定

目的 构建腺病毒穿梭质粒pShuttleCMV -BMP2 + -IRES -hrGFP - 1,为构建表达具有抗原表位标记的骨形态发生蛋白2 (bonemorphogeneticprotein 2 ,BMP - 2 ) ,并同时表达绿色荧光蛋白(greenfluorescentpro tein ,GFP)报告分子的腺病毒真核细胞表达载体打下基础。方法 对目的基因供体质粒pcDNA3-BMP2携带的BMP2基因测序和序列内部存在的限制性内切酶识别位点进行分析,利用PCR (polymeraschainreaction ,PCR)技术对pcDNA3-BMP2携带的BMP2基因突变,以去除翻译终止密码子后的基因序列并添加新的酶切识别位点XhoⅠ。测序检测突变情况,将突变后的BMP2基因(BMP2 + 基因)定向连入腺病毒穿梭质粒pShuttleCMV -IRES -hrGFP - 1,通过限制性内切酶酶切图谱分析鉴定获得的重组质粒。结果 重组质粒经双酶切鉴定图谱正确。结论 成功构建了pShuttleCMV BMP2 + IRES hrGFP -1。

从“shuttle bus”联想到“__车”的英译

车是现代社会和生活不可或缺的东西。随着社会的发展,科技的进步,车的花样也层出不穷,车名也日新月异。随着对外商务和文化交流日益频繁,对各种车的翻译成了涉外活动中尤其是英语应用者经常接触的内容。本文从剑桥商务英语中出现的shuttle bus英译开始,对车进行粗略的分门别类后并对各种车的翻译作简单的归纳,便于学习者日常记忆和应用。

Photovoltaic Performance of Triphenylamine Dyes-sensitized Solar Cells Employing Cobalt Redox Shuttle and Influence of π-conjugated Spacers

Developing photosensitizers suitable for the cobalt electrolyte and understanding the structure-property relationship of organic dyes is warranted for the dye-sensitized solar cells （DSSCs）. The DSSCs incorporating tris（1,10-phenanthroline）eobalt（Ⅱ/Ⅲ）-based redox elec- trolyte and four synthesized organic dyes as photosensitizers are described. The photovoltaic performance of these dyes-sensitized solar cells employing the cobalt redox shuttle and the influences of the w-conjugated spacers of organic dyes upon the photovoltage and photocur- rent of mesoscopic titania solar cells are investigated. It is found that organic dyes with thiophene derivates as linkers are suitable for DSSCs employing cobalt electrolytes. DSSCs sensitized with the as-synthesized dyes in combination with the cobalt redox shuttle yield an overall power conversion efficiency of 6.1% under 100 mW/cm2 AM1.5 G illumination.

Cellulose nanofiber separator for suppressing shuttle effect and Li dendrite formation in lithium-sulfur batteries

Lithium-sulfur battery(LSB) has high energy density but is limited by the polysulfides shuttle and dendrite growth during cycling. Herein, a free-standing cellulose nanofiber(CNF) separator is designed and fabricated in isopropanol/water suspension through vacuum filtration progress. CNFs with abundant polar oxygen-containing functional groups can chemically immobilize the polysulfides, and suppress the formation of the dendrites by controlling the surface morphology of the SEI on lithium metal in LSB. The isopropanol content in a suspension can fine-tune the pore structure of the membrane to achieve optimal electrochemical performance. The prepared separator displays integrated advantages of an ultrathin thickness(19 μm), lightweight(0.87 mg cm^(-2)), extremely high porosity(98.05%), and decent electrolyte affinity. As a result, the discharge capacity of the LSB with CNF separator at the first and 100 th cycle is 1.4 and 1.3 times that of PP separator, respectively. Our research provides an environmentalfriendly and facile strategy for the preparation of multifunctional separators for LSBs.

Construction of Shuttle Expression Plasmid and Stable Expression of Foreign Gene in Mycobacteria and E．Coli

By employing the pUC19 as a backbone,the regulatory and signal sequences which encode kanamycin resistance, and mycobacterial plasmid origin of replication (oriM) were cloned into the pUC19. The recombinant E. Coli-mycobacteria shuttle expression plasmid PBCG-8000 was constructed. The PBCG-8000 was able to replicate in both E. Coli and mycobacteria (including BCG) systems, and to confer stable kanamycin resistance upon transformants. The study should facilitate the development of BCG and other mycobacteria into multivalent vaccine vectors.

A gelatin-based artificial SEI for lithium deposition regulation and polysulfide shuttle suppression in lithium-sulfur batteries

Lithium-sulfur(Li-S) battery is one of the best candidates for the next-generation energy storage system due to its high theoretical capacity(1675 mA h-1),low cost and environment friendliness.However,lithium(Li) dendrites formation and polysulfide shuttle effect are two major challenges that limit the commercialization of Li-S batteries.Here we design a facile bifunctional interlayer of gelatin-based fibers(GFs),aiming to protect the Li anode surface from the dendrites growth and also hinder the polysulfide shuttle effect.We reveal that the 3D structural network of GFs layer with abundant polar sites helps to homogenize Li-ion flux,leading to uniform Li-ion deposition.Meanwhile,the polar moieties also immobilize the lithium polysulfides and protect the Li metal from the side-reaction.As a result,the anodeprotected batteries have shown significantly enhanced performance.A high coulombic efficiency of 96% after 160 cycles has been achieved in the Li-Cu half cells.The Li-Li symmetric cells exhibit a prolonged lifespan for 800 h with voltage hysteresis(10 mV).With the as-prepared GFs layer,the Li-S battery shows approximately 14% higher capacity retention than the pristine battery at 0.5 C after 100 cycles.Our work presents that this gelatin-based bi-functional interlayer provides a viable strategy for the manufacturing of advanced Li-S batteries.

Storage Assignment Optimization in a Multi-tier Shuttle Warehousing System

The current mathematical models for the storage assignment problem are generally established based on the traveling salesman problem（TSP）,which has been widely applied in the conventional automated storage and retrieval system（AS/RS）.However,the previous mathematical models in conventional AS/RS do not match multi-tier shuttle warehousing systems（MSWS） because the characteristics of parallel retrieval in multiple tiers and progressive vertical movement destroy the foundation of TSP.In this study,a two-stage open queuing network model in which shuttles and a lift are regarded as servers at different stages is proposed to analyze system performance in the terms of shuttle waiting period（SWP） and lift idle period（LIP） during transaction cycle time.A mean arrival time difference matrix for pairwise stock keeping units（SKUs） is presented to determine the mean waiting time and queue length to optimize the storage assignment problem on the basis of SKU correlation.The decomposition method is applied to analyze the interactions among outbound task time,SWP,and LIP.The ant colony clustering algorithm is designed to determine storage partitions using clustering items.In addition,goods are assigned for storage according to the rearranging permutation and the combination of storage partitions in a 2D plane.This combination is derived based on the analysis results of the queuing network model and on three basic principles.The storage assignment method and its entire optimization algorithm method as applied in a MSWS are verified through a practical engineering project conducted in the tobacco industry.The applying results show that the total SWP and LIP can be reduced effectively to improve the utilization rates of all devices and to increase the throughput of the distribution center.

Laboratory testing of a shuttle car canopy air curtain for respirable coal mine dust control

Canopy air curtain （CAC） technology has been developed by the National Institute for Occupational Safety and Health （NIOSH） for use on continuous miners and subsequently roof bolting machines in underground coal mines to protect operators of these machines from overexposure to respirable coal mine dust. The next logical progression is to develop a CAC for shuttle cars to protect operators from the same overexposures. NIOSH awarded a contract to Marshall University and J.H. Fletcher to develop the shuttle car CAC. NIOSH conducted laboratory testing to determine the dust control efficiency of the shuttle car CAC. Testing was conducted on two different cab configurations： a center drive similar to that on a Joy 10SC32AA cab model and an end drive similar to that on a Joy 10SC32AB cab model. Three different ventilation velocities were tested-0.61, 2.0, 4.3 rrds （120, 400, and 850 fpm）. The lowest, 0.61 m/s （120 fpm）, represented the ventilation velocity encountered during loading by the continuous miner, while the 4.3 m/s （850 fpm） velocity represented ventilation velocity airflow over the shuttle car while tramming against ventilation airflow. Test results showed an average of the dust control efficiencies ranging from 74 to 83% for 0.61 m/s （120 fpm）, 39%-43% for 2.0 m/s （400 fpm）, and 6%-16% for 4.3 m/s （850 fpm）. Incorporating an airflow spoiler to the shuttle car CAC design and placing the CAC so that it is located 22.86 cm （9 in.） forward of the operator improved the dust control efficiency to 51%-55% for 4.3 m/s （850 fpm） with minimal impact on dust control efficiencies for lower ventilation velocities. These laboratory tests demonstrate that the newly developed shuttle car CAC has the potential to successfully protect shuttle car operators from coal mine respirable dust overexposures.

Construction of a Shuttle Vector for Heterologous Gene Expression in Escherichia coli and Microalgae Anabaena

Theconstruction of an integrative shuttle expression vector and potential utility was reported inEscherichiacoliandAnabaena(Nostoc) sp. strain PCC 7120. The vector comprised of the following elements: (a) an intergenic non-coding region fromAnabaenato facilitate its genomic integration (b) a strong functional PpsbAIpromoter fromAnabaenafor desired gene expression and (c) neomycin phosphotransferase gene with its own promoter for the selection of transfor-mants. The constructed vectorpAnFP was evaluated by cloning, transfer and expression of thegfpgene encoding green fluorescent protein. When theE.coliandAnabaenasp. strain PCC 7120 were transformed, intensive green fluorescence produced by the products of GFP protein was observed. This result indicated that the integrative shuttle vector pAnFP can be promisingly used in genome transformation for expression of heterologous genes inE.coliand microalgae such asAnabaenaandNostocstrains.

Robust interface layers with redox shuttle reactions suppress the dendrite growth for stable solid-state Li metal batteries

Designing a durable lithium metal anode for solid state batteries requires a controllable and uniform deposition of lithium, and the metal lithium layer should maintain a good interface contact with solid state electrolyte during cycles. In this work, we construct a robust functional interface layer on the modified LiB electrode which considerably improves the electrochemical stability of lithium metal electrode in solid state batteries. It is found that the functional interface layer consisting of polydioxolane, polyiodide ion and Li TFSI effectively restrains the growth of lithium dendrites through the redox shuttle reaction of I-/I3-and maintains a good contact between lithium anode and solid electrolyte during cycles. Benefit from these two advantages, the modified Li-B anode exhibits a remarkable cyclic performance in comparison with those of the bare Li-B anode.

Unraveling Shuttle Effect and Suppression Strategy in Lithium/Sulfur Cells by In Situ/Operando X-ray Absorption Spectroscopic Characterization

The polysulfides shuttle effect represents a great challenge in achieving high capacity and long lifespan of lithium/sulfur(Li/S)cells.A comprehensive understanding of the shuttle-related sulfur speciation and diffusion process is vital for addressing this issue.Herein,we employed in situ/operando X-ray absorption spectroscopy(XAS)to trace the migration of polysulfides across the Li/S cells by precisely monitoring the sulfur chemical speciation at the cathodic electrolyte-separator and electrolyte-anode interfaces,respectively,in a real-time condition.After we adopted a shuttle-suppressing strategy by introducing an electrocatalytic layer of twinborn bismuth sulfide/bismuth oxide nanoclusters in a carbon matrix(BSOC),we found the Li/S cell showed greatly improved sulfur utilization and longer life span.The operando S Kedge XAS results revealed that the BSOC modification was bi-functional:trapping polysulfides and catalyzing conversion of sulfur species simultaneously.We elucidated that the polysulfide trapping-and-catalyzing effect of the BSOC electrocatalytic layer resulted in an effective lithium anode protection.Our results could offer potential stratagem for designing more advanced Li/S cells.

Strategies to suppress the shuttle effect of redox mediators in lithium-oxygen batteries

Rechargeable lithium-oxygen(Li-O_(2))batteries are the next generation energy storage devices due to their ultrahigh theoretical capacity.Redox mediators(RMs)are widely used as a homogenous electrocatalyst in non-aqueous Li-O_(2)batteries to enhance their discharge capacity and reduce charge overpotential.However,the shuttle effect of RMs in the electrolyte solution usually leads to corrosion of the Li metal anode and uneven Li deposition on the anode surface,resulting in unwanted consumption of electrocatalysts and deterioration of the cells.It is therefore necessary to take some measures to prevent the shuttle effect of RMs and fully utilize the soluble electrocatalysts.Herein,we summarize the strategies to suppress the RM shuttle effect reported in recent years,including electrolyte additives,protective separators and electrode modification.The mechanisms of these strategies are analyzed and their corresponding requirements are discussed.The electrochemical properties of Li-O_(2)batteries with different strategies are summarized and compared.The challenges and perspectives on preventing the shuttle effect of RMs are described for future study.This review provides guidance for achieving shuttle-free redox mediation and for designing Li-O_(2)cells with a long cycle life,high energy efficiency and highly reversible electrochemical reactions.

ANALYSIS OF N-METHYL-N-NITROSOUREA-INDUCED MUTATIONS IN A SHUTTLE VECTOR PLASMID PROPAGATED IN MOUSE O^6-METHYLGUANINE-DNA METHYLTRANSFERASE-DEFICIENT CELLS IN COMPARISON WITH PROFICIENT CELLS.

To investigate a contribution of O-methylguanineto mutagenesis in mouse cells,we constructed ashuttle vector plasmid,pYZ289,from a part ofpZ189 plasmid and polyoma virus DNA.The plasmidcontains a supF gene as a marker of mutation andcan replicate in both E.coli and mouse cells.ThepYZ289 treated with N-methyl-N-nitrosourea (MNU)