Recent progress and future perspectives of flexible metal‐air batteries

With the rapid development of wearable and intelligent flexible electronic devices(FEDs),the demand for flexible energy storage/conversion devices(ESCDs)has also increased.Rechargeable flexible metal‐air batteries(MABs)are expected to be one of the most ideal ESCDs due to their high theoretical energy density,cost advantage,and strong deformation adaptability.With the improvement of the device design,material assemblies,and manufacturing technology,the research on the electrochemical performance of flexible MABs has made significant progress.However,achieving the high mechanical flexibility,high safety,and wearable comfortability required by FEDs while maintaining the high performance of flexible MABs are still a daunting challenge.In this review,flexible Zn‐air and Li‐air batteries are mainly exemplified to describe the most recent progress and challenges of flexible MABs.We start with an overview of the structure and configuration of the flexible MABs and discuss their impact on battery performance and function.Then it focuses on the research progress of flexible metal anodes,gel polymer electrolytes,and air cathodes.Finally,the main challenges and future research perspectives involving flexible MABs for FEDs are proposed.

Recent progress in rechargeable alkali metal-air batteries

Rechargeable alkali metal-air batteries are considered as the most promising candidate for the power source of electric vehicles(EVs) due to their high energy density. However, the practical application of metal-air batteries is still challenging. In the past decade, many strategies have been purposed and explored, which promoted the development of metal-air batteries. The reaction mechanisms have been gradually clarified and catalysts have been rationally designed for air cathodes. In this review, we summarize the recent development of alkali metal-air batteries from four parts: metal anodes, electrolytes, air cathodes and reactant gases, wherein we highlight the important achievement in this filed. Finally problems and prospective are discussed towards the future development of alkali metal-air batteries.

Mesoscopic numerical computation model of air-diffusion electrode of metal/air batteries

This work creates a droplet battery model based on the electrolyte performance in the porous electrode, studies the current density on the mesoscopic scale, and explains how the mesoscopic structure of the porous electrode influences the current density on the air-diffusion electrode. Near the three-phase line, there is a strong band containing nearly 80% current. For porous electrodes, the total current is proportional to the length of the strong band. Thus, it can be inferred that on the macroscopic scale, the longer the total length of the strong band on unit area is, the larger the current density is.

Distribution and Concentrations of Heavy Metals in Tropospheric Suspended Particulate Matter (PM10) In Nairobi City, Kenya

Air pollution present the greatest threat to human health and welfare in urban environments. Population growth, industrial activities, expanded transport system, vehicular traffic, poor road planning, poor land use and traffic congestion contribute to the problem. Particulate matter (PM2.5 and PM10) has become the principal pollutants due to increased material use, energy demand and use as a result of global economic growth. This study assessed the levels of PM10 in ambient air and heavy metal composition in Nairobi city. Sampling sites were classified into three categories namely;controlled areas, industrial and residential areas as proscribed in the EMCA Air Quality Regulations, 2014. Portable Mini-Vol ambient air samplers were used for fine particulate monitoring. The concentrations of manganese, lead, and cadmium was determined in PM10 samples from all sampling sites. The lead concentration mean was 0.07 ± 0.06 μg/m3, 0.34 ± 0.35 μg/m3 and 1.10 ± 0.59 μg/m3 for residential, controlled and industrial areas respectively. Generally, all afternoons had high particulate matter while the lowest concentration levels of PM10 were recorded at night.

Metal hydride air conditioner

The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi_ 4.4 Mn_ 0.26 Al_ 0.34 / La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 ,LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Nd_ 0.4 Ni_ 4.8 Mn_ 0.2 Cu_ 0.1 and LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 , were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small weight, heat capacity and good heat conductivity of the reaction beds. An experimental metal hydride air-conditioning system was established by using LaNi_ 4.61 Mn_ 0.26 Al_ 0.13 /La_ 0.6 Y_ 0.4 Ni_ 4.8 Mn_ 0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and W_ net =0.09 kW/kg.

Treatment of Wastewater Containing Heavy Metals Using Dissolved Air Released Flotation Column

A new type of dissolved air released flotation column is developed to treat wastewater containing Cr(VI)based on advantages of both dissolved air floatation and column floatation. By using a column with a diameter of 50mm and a specially made dissolved air releaser, micro-bubbles inside the column can be formed. N2H4·H2O was usedas reductant, AlCl3 as flocculant, C12H25SO3Na(SDS) as surfactant in the experiment. The effects of pH of wastewa-ter, pressure of dissolved air, ratio of return water, and concentration of flocculant and surfactant on the removal effi-ciency are studied. The results show that the efficiency of dissolved air released flotation column is much higher thanthat of other approaches after the operation parameters are optimized, with the reduction ratio of Cr(VI) in wastewaterreaching 98%. So this technique can be widely used in wastewater treatment.

Trace Metals in Fine and Respirable Ambient Air Particulates on Trinidad’s West Coast

The paper analyzed the concentrations of trace metals in fine and respirable particulates (fine-PM1 and PM2.5;respirable-PM10) to determine baseline concentrations in the ambient air and the factors impacting its distribution such as land use and time of year when levels may be concerning to public health. Measurements of particulates along with meteorological parameters were made at four sites over the heavily populated west coast of Trinidad (10°32'N, 61°18'W) during March ’15-May ’16, representing rural, urban, mixed background and industrial land uses. The study found mean levels of trace metals to be highest at the industrial and urban stations. Public health exceedances (referenced to the Canadian AAQ public health standards (Ontario-MoE, 2012)) were measured for beryllium, cadmium, chromium, iron, manganese and nickel (in PM10). Iron, manganese and nickel, most associated with particulates at the industrial station, were in frequent exceedance. Beryllium—concentrated in coarse PM (PM2.5-10) with only a single measured exceedance at the mixed background station likely poses minimal threat to the health of the nearby population. Cadmium—concentrated in fine PM which peaked once only at the rural station was likely due to an irregular event within a narrow timeframe during the time of sampling. Iron and manganese were frequently above the Canadian public health threshold, but predominated in the coarse PM fraction, suggesting localised sources. Nickel, concentrated in the fine PM fraction, was frequently in exceedance particularly at the industrial station. Cadmium and nickel are genotoxic and should be regulated in order to reduce the burden of toxic carcinogens to which the population can be exposed.

球形敏感单元微瞄准形成金属/空气/金属微观界面中的电子输运机理研究

针对惯性陀螺和航空、航天发动机等高端/尖端仪器装备中,深孔、沟槽等内腔体结构的高精度测量对非接触传感方法提出的挑战性需求,展开球形敏感单元瞄准被测件形成金属/空气/金属微观界面中的敏感机理研究。从绝缘介质薄层电子输运机理和绝缘介质性质改变而产生电子输运两个角度,对包括电子隧穿在内的电子输运机理进行形成条件和电流密度特性的分析,揭示球形敏感单元微瞄准形成的金属/空气/金属微观界面中,产生传感电流的电子输运主要机理为福勒-诺德海姆隧穿效应,为探索新原理的三维非接触式纳米传感方法奠定了基础。

煅烧对空气电极的多孔结构和电化学性能的影响

优化空气电极的孔道结构对提升电极的电化学性能至关重要。通过电极多孔结构的重组,可以提高氧气的传输速率,从而实现金属空气电池的高能量密度和长放电寿命。采用扫描电镜、差热分析仪、比表面积测试仪、润湿角测试仪和电化学测试仪等检测技术,研究了不同煅烧温度(200、250、300、350、400℃)对空气电极的表观形貌、微孔结构和电化学性能的影响,并进一步测试了镁基空气电池的放电性能。结果表明,随着煅烧温度升高,电极中黏结剂聚四氟乙烯(PTFE)的纤维熔融状态改变了其微孔结构分布(包括气孔和液孔),从而影响了电极的氧还原电化学性能和放电寿命。尤其在接近PTFE相变点(343℃)的煅烧温度350℃下制备的空气电极,具有均匀的孔径分布和最佳疏水特性(包含疏水点和气体扩散孔道)。因此,空气电极表现出最小电极极化(-0.45 V极化电位下,电极电流密度为159.1 mA/cm^(2))、最长放电寿命(15 mA/cm^(2)电流密度下,放电时长为39.0 h),较大的容量及功率密度(分别为37.4 A·h和13.05 mW/cm^(2))。

金属气囊膨胀性能影响因素研究

金属气囊具有较强的承压能力和良好的气密性、形状稳定性及环境适应性,在各类航天器做动变形及减振抗冲击结构设计中成为行业研究热点。主要研究了气囊膨胀过程中导致断裂或褶皱失稳等现象的关键参数,同时分析了进气口位置和气囊边缘厚度对膨胀效果的影响。采用有限元方法,选用5组常用金属材料参数为基础数据,对材料的密度、弹性模量、泊松比和屈服极限进行正交试验。仿真结果表明,金属气囊最大膨胀高度受材料密度影响最大,极差为8.26 mm;最大褶皱深度受屈服极限影响最大,极差为5.48 mm;褶皱数受屈服极限影响最小,极差仅为0.8个;虽然进气口位置将影响气囊膨胀的均匀性,但会在特定区域达到更大的膨胀高度;虽然提高边缘厚度会增加气囊的强度,但会降低气囊最大膨胀高度。结果可为金属气囊的工程设计提供理论参考。

可控构建分级多孔炭载CoP纳米颗粒催化剂用于高效氧还原反应

为金属空气电池等热点能源器件中的阴极氧还原反应(ORR)设计低成本和高效率的无贵金属催化剂仍然是一项巨大的挑战。过渡金属磷化物(TMPs)因其可调的电子结构及优异的催化性能,有望替代贵金属催化剂。本文采用磷化策略(350℃下二次热解),构建了一种在分层多孔炭框架上负载由掺氮炭壳包裹的CoP纳米颗粒催化剂(CoP@NC)。在二次热解过程中,Co纳米颗粒在NaH_(2)PO_(2)生成的PH_(3)气体下原位转化为CoP纳米颗粒,而载体的十二面体结构没有发生改变。在碱性条件下,CoP@NC电催化剂表现出优异的ORR活性,半波电位高达0.92 V,这归因于分散良好的CoP纳米颗粒与炭壳之间的协同耦合以及载体多孔结构实现的高效质量传输。此外,使用CoP@NC组装的锌-空气电池展现出1.51 V的高开路电压和210.1 mW cm^(-2)的功率密度。这项研究将有助于开发低成本和高效率的ORR电催化剂。

金属有机骨架及其衍生材料在电解水和锌-空气电池中的应用

电解水和锌-空气电池(ZABs)技术为解决能源危机、实现碳中和目标开辟了一条新的途径。然而,这些技术的实际应用在很大程度上受到析氢反应(HER)、析氧反应(OER)以及氧还原反应(ORR)缓慢动力学的限制。因此,迫切需要开发高效、稳定的电催化剂有效降低反应过电位,加快电催化反应进程。金属有机骨架(MOFs)由于其灵活可调的组成和精确可控的结构,已成为催化领域研究最广泛的材料之一。本文聚焦于MOFs基电催化剂的制备策略和结构特性,主要介绍它们在电解水和ZABs方面近期的研究进展,并对该领域存在的问题和发展趋势进行了总结和展望。

金属空气预过滤器在某核电站AC厂房的应用

根据某核电站AC厂房送风系统要求和框架文件设计了一种可复用的金属空气预过滤器,与核电站原空气预过滤器的安装方案和运行压差进行了对比。结果表明,运行相同时间后,金属空气预过滤器上游、下游压力和压差上升比例均低于原空气预过滤器,表明金属空气预过滤器运行更稳定。达到终阻力时,金属空气预过滤器可清洗后复用,有良好的应用前景。

电活性聚乳酸纳纤膜的形态调控及高效捕集PM_(0.3)性能

通过静电喷雾沸石咪唑框架-8(ZIF-8)分散液对同步电纺聚乳酸(PLA)纳米纤维进行表面功能化,以增强PLA/ZIF-8纳米纤维膜(简称纳纤膜)表面的电荷俘获及储存能力,从而提高静电吸附效果和过滤性能.通过在分散液中添加不同量的ZIF-8来调控锚定于纤维表面的ZIF-8负载量,探究ZIF-8含量与纤维膜形态和性能演变之间关系.采用扫描电子显微镜(SEM)对纤维膜的微观形态进行表征,并结合傅里叶变换红外光谱(FTIR)和X射线衍射谱(XRD)分析了纤维膜的化学性质、界面相互作用和晶体结构的演变机理.采用静电测试仪、电介质测试仪和静电计分别评价表面电势、相对介电常数和输出电压,表征纤维膜的电活性和摩擦电输出性能.通过万能试验机测试聚乳酸纳米纤维膜的力学性能,并使用自主搭建的空气过滤测试平台探究纤维膜高效过滤机理.结果表明,PLA/ZIF-8纳纤膜具有高电活性、高过滤效率、低空气阻力和优异的力学性能:其表面电势和最大开路输出电压分别可达5.9 kV和30.9 V,与纯PLA对比样相比分别提升5.6倍和5.3倍,同时拉伸强度和拉伸韧性增幅分别高达78%和111%.更重要的是,PLA/ZIF-8纳纤膜的PM0.3过滤性能得到大幅提升(增幅可达12.6%),且空气阻力有所降低(40 Pa,65 L/min).所制备的环境友好型PLA/ZIF-8纳纤膜在滤除超细颗粒物和阻断病毒气溶胶传播等领域具有广阔应用前景.

不同空气质量下河南主要城市冬季PM_(2.5)中重金属污染特征、来源解析及健康风险评价

为研究不同大气污染水平条件下河南区域PM_(2.5)及其载带金属的浓度特征、来源和健康风险,于2020年12月在河南7个主要城市(郑州市、洛阳市、信阳市、安阳市、新乡市、商丘市、许昌市)采集PM_(2.5)样品,测定并分析了元素Cu、Zn、Pb、Se、Mn、Fe、As、Mo、Ni、Cd、Al.结果表明,PM_(2.5)中的重金属浓度峰值集中在轻度和中度污染空气质量条件,平均浓度顺序Zn>Fe>Al>Mn>Pb>Cu>As>Se>Mo>Cd>Ni.Zn和Fe平均质量浓度分别为118.92 ng·m^(-3)和52.88 ng·m^(-3),两者之和占重金属总浓度的65.88%.重金属富集因子变化趋势与浓度变化趋势相同,Cd元素的富集因子最高(>10),表明主要受人为活动影响.重金属元素的主要污染源为燃烧源和交通源.健康风险评估显示,所有空气质量条件下均为成年男性的致癌风险最大,儿童的非致癌风险最大.空气质量条件为优时,Mo对暴露于环境中1 h的成年男性和成年女性具有潜在致癌风险.

环境污染与DR的关系研究进展

糖尿病视网膜病变(DR)是由持续高血糖状态导致的一种慢性进行性视网膜病变,已成为我国人群中重度视力损伤和盲的主要原因之一。然而,目前对于DR发生和发展的相关因素仍未完全明确。目前研究确认的部分环境污染物,如空气颗粒物、硫化氢、钴、镉、铯、邻苯二甲酸酯、甲基乙二醛和2-哌啶酮等,可能会通过氧化应激、炎症反应和血管内皮细胞生长因子的相关通路增加DR的发病风险或加速病程进展。为了明确环境污染物暴露与DR之间的因果关系和剂量-反应关系,仍需要进一步研究探索具体的发病机制,并进行对环境暴露量化测量的纵向研究。本文就包括空气污染、重金属污染和化学污染在内的环境污染物与DR相关的近期流行病学研究结果和病理生理机制进行综述。

辐射空调系统供暖特性试验研究

为探究辐射空调系统供暖特性,搭建辐射空调系统试验台,进行7 d的系统间歇运行试验,对两级新风机组送风温湿度,空气源热泵主机制热量、能效比,以及系统能耗和能效比进行分析。结果表明,在设定参数下,两级新风机组稳定时送风温湿度分别为27℃和35%左右,空气源热泵主机平均制热量为4.5 kW,制热性能系数(COPU)为4.10;辐射空调系统耗电量为1.5 kW·h,系统性能系数(COPS)为3.02。试验结果可为系统的进一步优化和推广提供参考。

ZIF-67衍生负载Co/Co 9S 8碳材料作为ORR催化剂的研究

锌-空气电池作为一种重要的电化学能源存储和转换技术,因其能量密度高、成本低和环境友好等优点受到广泛关注。然而,由于其空气阴极缓慢的动力学反应,阻碍了锌-空气电池的进一步发展。因此,我们采用了一种水热-高温热解-氨气还原的方法,制备出ZIF-67衍生N掺杂碳基Co和Co_(9)S_(8)纳米颗粒的电催化剂(Co/Co_(9)S_(8)@NC-1)。电化学测试结果表明,该催化剂具有优异的ORR催化活性,其半波电位为0.85 V,接近商用Pt/C。与基于Pt/C+Ir/C的锌-空气电池(开路电压:1.47 V)相比,Co/Co_(9)S_(8)@NC-1基的锌-空气电池具有1.51 V的开路电压,且表现出105.3 mW/cm的功率密度和172 h循环稳定性(Pt/C+Ir/C:147 h)。此工作为开发非贵金属基ORR催化剂提供了有效途径。

陇南市某生活垃圾填埋场周边土壤及空气污染状况分析

对垃圾填埋场周围土壤以及空气进行污染调查与评价是十分必要的,其周边环境的好坏以及是否受到污染对周边群众的健康具有很大的影响。本研究以陇南市武都区生活垃圾填埋场为研究对象,测定了填埋场周边土壤中镉、铅、铜、锌、铬等8种重金属的含量,以及厂界和周边空气敏感村庄主要恶臭物质氨、硫化氢和挥发性有机物的含量。结果表明部分区域土壤中重金属砷、汞、镉的污染超标,夏季填埋场对周边环境空气的影响较大,应重视填埋场夏季臭气及挥发性有机物污染。