Research on the impact of high-temperature aging on the thermal safety of lithium-ion batteries

Understanding the thermal safety evolution of lithium-ion batteries during high-temperature usage conditions bears significant implications for enhancing the safety management of aging batteries.This work investigates the thermal safety evolution mechanism of lithium-ion batteries during high-temperature aging.Similarities arise in the thermal safety evolution and degradation mechanisms for lithium-ion batteries undergoing cyclic aging and calendar aging.Employing multi-angle characterization analysis,the intricate mechanism governing the thermal safety evolution of lithium-ion batteries during high-temperature aging is clarified.Specifically,lithium plating serves as the pivotal factor contributing to the reduction in the self-heating initial temperature.Additionally,the crystal structure of the cathode induced by the dissolution of transition metals and the reductive gas generated during aging attacking the crystal structure of the cathode lead to a decrease in thermal runaway triggering temperature.Furthermore,the loss of active materials and active lithium during aging contributes to a decline in both the maximum temperature and the maximum temperature rise rate,ultimately indicating a decrease in the thermal hazards of aging batteries.

Martensite Aging Effect and Thermal Cyclic Characteristics in Ti-Pd and Ti-Pd-Ni High Temperature Shape Memory Alloys

The effect of thermal cycling and aging in martensitic state in Ti-Pd-Ni alloys were investigated by DSC and TEM observations. It is shown that the thermal cycling causes the decreases in M, and Af temperatures in Ti50Pd50-xNix (x=10, 20, 30) alloys, but no obvious thermal cycling effect was observed in Ti50Pd50Pd40Ni10 alloys and the aging effect shows a curious feature, i.e., the Af temperature does not saturate even after relatively long time aging, which is considered to be due to the occurrence of recovery recrystallization during aging.

Cyclic feeding regime may delay aging in animals by enhancing the hepatocytes nuclei structure

Background:The liver is fundamental for keeping up the entire body’s homeostasis.The liver hepatocytes have been shown to undergo genomic instability with aging.The stability of the hepatocytes depends on its nuclear architecture.Calorie restriction has been shown to extend life-span favorably and this may be through the reorganization of the nuclear structure.Objective:To study the effect of cyclic feeding regime on the chromatin assembly anchored to the nuclear membrane scaffold of rat models hepatocytes nuclei.Method:Rats models underwent cyclic feeding regime,after which nuclei were isolated;then,we investigated the chromatin decondensation and nuclear membrane disintegration of the hepatocytes using fluorescence imaging methods.Results:In 60 seconds,protease decondensed the chromatin and disintegrated the nuclear membrane structure of controls.After the first fasting,the time increased to 145 seconds in 3-month-old rats.The first refeeding increased the time to 156 seconds with a further rise to 340 seconds following the second fasting,then dropped to 116 seconds by the second refeeding.20 months old rats showed 186 seconds increase in the time of chromatin decondensation and nuclear membrane disintegration after the first fasting,with a decrease to 140 seconds observed after first refeeding.The second fasting increased the time to 165 seconds,which then slightly decreased to 163 seconds after the second refeeding.Conclusion:These results show that intermittent fasting may have acted on chromatin histone interactions and the structural lamin networks of the nuclear membranes in bringing about nuclear stability,which is essential for normal cellular function.

Enhancing corrosion resistance of 7150 Al alloy using novel three-step aging process

The effects of a novel three-step aging process （T76＋T6） on the electrochemical corrosion behavior of 7150 extruded aluminum alloy were evaluated and compared with those of the conventional retrogression and re-aging process （T77）. The open circuit potential （OCP）, cyclic polarization and electrochemical impedance spectra （EIS） of the A1 alloys were measured after treatment in three solutions （3.5% NaCl （mass fraction）; 10 mmol/L NaCl ＋ 0.1 mol/L Na2SO4; 4 mol/L NaCl ＋ 0.5 mol/L KNO3 ＋ 0.1 mol/L HNO3）. The parameters including the corrosion potential, pitting potential, pit transition potential and steepness, and potential differences were extensively discussed to evaluate the corrosion behavior of the Al alloys. The electrochemical and scanning electron microscopy （SEM） data show that compared with the 7150-T77 Al alloy, the T76 ＋ T6 aged 7150 A1 alloy exhibits better resistance to pitting corrosion, inter-granular corrosion （IGC） and exfoliation corrosion, which is attributed to further coarsening and inter-spacing of the grain boundary particles （GBPs） as revealed by transmission electron microscopy. Furthermore, the hardness tests indicate that an attractive combination of strength and corrosion resistance was obtained for the 7150 Al alloy with T76 ＋ T6 treatment.

T6态热挤压Al-5Cu-0.8Mg-0.15Zr-0.2Sc-0.5Ag合金的低周疲劳行为

为了揭示经过T6处理的热挤压Al-5Cu-0.8Mg-0.15Zr-0.2Sc-0.5Ag合金在不同温度下的低周疲劳变形与断裂行为,对T6态热挤压合金进行了室温和200℃条件下的低周疲劳实验。结果表明:在室温和200℃下合金塑性应变幅与载荷反向周次之间服从Coffin-Manson公式,而弹性应变幅与载荷反向周次之间服从Basquin公式;合金在室温和200℃下低周疲劳变形时,在较低外加总应变幅下疲劳变形机制主要为平面滑移,而在较高外加总应变幅下疲劳变形机制主要为波状滑移;室温和200℃下合金的疲劳裂纹均萌生于疲劳试样表面并以穿晶方式扩展。

Corrosion evolution of high-temperature formed oxide film on pure Sn solder substrate

The evolution of morphology, composition, thickness and corrosion resistance of the oxide film on pure Sn solder substrate submitted to high-temperature aging in 150 °C dry atmosphere was investigated. The results indicate that high-temperature aging accelerates the dehydration of Sn(OH)_(4)in the pre-existing native oxide film to form SnO_(2)and facilitates the oxidation of fresh Sn substrate, resulting in the gradual increase in oxide film thickness and surface roughness with prolonging aging time. However, the corrosion resistance of the film initially is enhanced and then deteriorated with an extending aging time. Besides, the formation and evolution mechanisms of the oxide film with aging time were discussed.

Aging Behaviors of Silicone Rubber Composite Materials under Outdoor Environment

We investigated the aging effect on the chemical structure of silicone rubber composite materials under outdoor environment. The variations of low molecular weight siloxanes in silicone rubber were probed by gas chromatography-mass spectrometry during the degradation process. The experimental results indicate that a series of cyclic siloxanes exist in both the virgin and aged silicone rubber samples, while the additional low molecular weight siloxanes（hexamethyl cyclotrisiloxane） only appear in the aged samples. Meanwhile, the total amounts of low molecular weight siloxanes in the aged samples are much less than those in the virgin ones. The loss of low molecular weight siloxanes is induced by the chain scission and depolymerization.

The Cyclic Feeding Regime Induces Decaying Age-Dependent Oxidative Stress and Regulates the Cell Chain of the Immunity

We developed an experimental model of a cyclic feeding regime (CFR) that increased a lifespan in rats. The manifestations of oxidative stress and their interrelation with parameters of cell immunity were assessed in rats at CFR. It is shown that changes of body mass, liver mass and indexes of pro/antioxidant system after periods of starving—ad libitum nutrition at CFR diet in old animals were less pronounced than in young animals. The body mass loss of 30% in 14 days was accompanied by oxidative stress. Indexes of phagocytosis did not change, but activity of oxidase system of neutrophil was increased in 2 times. The response of metabolic and physiological systems on repeat starving—ad libitum nutrition cycles differs from the response to the initial cycle of CFR. This is interpreted as a change of adaptation strategy and the effect of metabolic memory, which influences the choice of organism strategy of adaptation for subsequent starving. The dynamics of change of the studied indexes in response to CFR was age-dependent. It was supposed that different answer to CFR in young and old animals is determined by the different amount of carbon and fat depots in young and old animals.

Ag/AgCl和碳纤维海洋电场电极的探测特性研究

使用烧结法制备了Ag/AgCl固态不极化海洋电场电极,利用聚丙烯腈碳纤维T300制备了电容型海洋电场电极。研究了不极化电极和电容型电极探测海洋电场的原理,提出了两种电极的使用方法并研究了其探测性能。使用电化学工作站对两种电极进了循环伏安测量和电极对极差跟踪;使用低频低噪声放大器对两种电极的自噪声稳定速度和大小进行对比测量;在自制水槽中测试了两种电极在不同频率下的响应性能。试验结果表明两种电极均可测量1 m Hz以上的交变海洋电场;相比于Ag/AgCl电极,碳纤维电极具有极差小和自噪声稳定速度快的特点;稳定后两种电极的自噪声均为1 n V/√Hz@1 Hz。

循环伏安法制备Ag纳米线阵列

In this paper, highly ordered anodic aluminum oxide (AAO) template with hexagonal close-packed arrays was successfully fabricated through a two-step anodization process. Ag nanowire arrays with high aspect ratio were prepared using cyclic voltammetry within the confined nanochannels of AAO template. In addition, standing Ag nanowire arrays free-support of templates were also fabricated successfully by cyclic voltammetry method. The micrographs and crystal structures of Ag nanowires were studied by field emission scanning electron microscope (FESEM) and X-ray diffraction (XRD). FESEM observation showed that the Ag nanowire arrays with high aspect ratio lie orderly on the surface of the substrate. The diameter of the Ag nanowire is about 60 nm and the length up to 30 靘 or more. While the controlled nanowire arrays exhibit highly ordered structure in large area and the standing Ag nanowire in the array has the length of 1 靘 and good orientation. XRD results illustrated that the Ag nanowires in the arrays deposited by cyclic voltammetry method have a face centered cubic structure and are preferentially oriented in the (220) direction.

Pb-0.3%Ag-0.06%Ca三元合金阳极在锌电积过程中的电化学行为—循环伏安曲线研究

Pb-0.3%Ag-0.06%Ca三元轧制合金阳极在酸性硫酸锌溶液中进行了360 h(15 d)的恒电流极化.通过循环伏安技术研究分析了恒电流极化过程中合金阳极的电化学行为的变化.通过X射线衍射技术分析了合金阳极在恒电流极化过程中形成的氧化膜物相.结果表明:合金阳极的阳极氧化膜形成和稳定需要一个过程.在这个过程中,电化学行为和氧化膜物相呈现明显的变化.随着恒电流极化时间的延长,阳极峰(Pb→PbSO4)的强度在前两天的电解中显著升高,其后保持在稳定状态(0.25 mA/cm2),同时向正方逐渐移动.然而阳极峰(PbSO4→β-PbO2,PbO→α-PbO2)却显著地向负方向移动.阴极峰(β-PbO2和α-PbO2→PbSO4)和(PbO和PbSO4→Pb)呈现一个逐渐增加的趋势,同时逐渐的向负方向移动.而且合金阳极氧化膜的腐蚀物相主要为PbSO4、α-PbO2、β-PbO2、PbS2O3和Pb.随着电解时间的延长,PbSO4峰逐渐变弱,α-PbO2峰逐渐增强.PbSO4择优取向为(021)、(121)和(212)晶面.α-PbO2的择优取向为(111)晶面.

高价银配合物AgL(ClO_4)_2的合成、表征及循环伏安研究

合成了一种四氮杂大环高价银配合物AgL(ClO4) 2 ,其中L为 5,1 2 -二甲基 - 7,1 4二苯基 - 1 ,4,8,1 1 -四氮杂环十四烷 (简写Ph2 Me2 [1 4]aneN4)。经元素分析、红外光谱、摩尔电导、电子顺磁共振等方法对配合物进行了表征 ,并研究了它的循环伏安性质。

High-temperature Thermo-oxidative Aging of Vulcanized Natural Rubber Nanocomposites:Evolution of Microstructure and Mechanical Properties

The aging of natural rubber(NR)at high temperatures will seriously affect its service lifetime in many key applications.In the present work,the changes in microstructure and mechanical properties of semi-efficient vulcanized NR/carbon black(CB)vulcanizates during thermooxidative aging at high temperatures(150-200℃)and a moderate temperature(95℃)were compared.At high temperatures,a two-stage aging behavior,which was characteristic of a first rapid decline and then a continuous rise in the crosslinking density(ve),was identified and was found to be closely related to the depletion behavior of antioxidants.The surface cracking behavior observed in the second stage of high-temperature aging was discussed in terms of the grafting reaction of macromolecular radicals on CB particles and thermal expansion.In contrast,the aging of NR at moderate temperatures was much mild,which featured a continuous increase in ve and an oxidation mechanism dominated by peroxy radicals attacking double bonds.In general,the mechanical properties of NR vulcanizates during high-temperature aging depended on the competition effects of structural evolution in the crosslinked network and oxidation-induced chain scission.

Thermal fatigue behaviors of SiC power module by Ag sinter joining under harsh thermal shock test

The excellent properties of SiC bring new challenges for the device packaging.In this study,the bonding strength,fracture behaviors and microstructural evolution of micron-porous Ag joint were elevated during thermal cycling(–50 ℃–250 ℃) in SiC/DBC(direct bonding copper) die attachment structure for different time.During harsh thermal shock test,the strength of sintered joint deceased gradually with the increase of cycling number,and the value just was half of the value of as-sintered after 1 000 cycles.Coarsening of Ag grains was observed in micron-porous joint with the structure inhomogeneity and defects increasing,which were the reasons of the strength decease.In addition,it was also found that the fracture behavior of sintered joints was changed from ductile deformation of Ag grain to brittle fracture of crack propagation after 1 000 cycles.This study will add the understanding in the mechanical properties of Ag sinter joining and its applications at high temperature.

三维Ag/TiO_2纳米网的制备及其光催化性能研究

采用阳极氧化法在钛网上制备了TiO_2纳米管阵列,并利用循环伏安法在纳米管表面沉积Ag,制备出Ag/TiO_2纳米复合材料。采用扫描电子显微镜、X-射线衍射仪、紫外-可见漫反射光谱等方法对复合材料的形貌、结构、光电性能进行了表征,并以2,4-二硝基苯酚为模型化合物考察了沉积Ag对复合材料光催化性能的影响。结果表明,沉积5圈Ag的Ag/TiO_2复合纳米材料光催化性能最佳,在模拟太阳光照射120 min后,2,4-二硝基苯酚可被完全降解。

Al-Cu-Mg-Ag新型耐热铝合金循环蠕变时效研究

采用矩形波加载方式,对Al-Cu-Mg-Ag新型耐热铝合金进行循环蠕变时效处理,采用力学性能测试、耐腐蚀性能测试,并结合电化学分析、透射电镜分析和金相显微分析等,研究了循环蠕变时效对Al-Cu-Mg-Ag合金的微观组织与性能的影响。试验结果表明:循环蠕变时效能够提高合金的力学性能和抗腐蚀性能。循环蠕变时效能够细化合金中晶内和晶界析出相,促进θ′相析出,减小无沉淀析出带宽度,晶粒沿着蠕变方向被拉伸。200 MPa下循环蠕变试样综合性能最佳。

循环老化三元锂离子电池热失控气体毒性研究

为研究高能量密度锂离子电池循环老化过程中热失控特性变化及释放气体的毒性危害,对不同循环老化程度的三元锂离子电池进行热滥用实验,利用气体传感器阵列,基于有效剂量分数模型对热失控气体毒性危害进行定量分析。结果表明,高镍含量三元锂离子电池循环性能差,200次循环老化后,电池健康状态低于70%。老化电池更容易进入热失控状态,热失控反应更剧烈但释放能量少,释放气体燃烧效率低。在密闭空间内,电池热失控释放窒息性气体危害性比刺激性气体更高,150次循环老化电池的窒息性气体毒性累积效应比新鲜电池早638 s达到临界值1。随老化程度增加,最终电池的刺激性气体毒性即时效应与气体致死毒性即时效应降低,与新鲜电池相比,100次循环老化后,电池的刺激性气体毒性即时效应降低0.34,气体致死毒性即时效应降低0.19。研究结果可为老化电池安全性评估及热失控预警提供数据支撑。

海上风电塔筒钢构防腐蚀涂料耐循环老化性能研究

本文基于标准ISO12944-9:2018附录B循环老化试验方法对四家厂家生产的涂层板进行试验,结果表明以海洋飞溅区中SigmaZinc 109G+Sigmcover 410+PSX 700 RAL9003的底漆+中间漆+面漆的涂层体系最优,以海洋大气区中环氧玻璃鳞片+环氧玻璃鳞片+氟碳的底漆+中间漆+面漆的涂层体系最优,为海上风电塔筒的选材具有参考意义。

Effect of physical aging and cyclic loading on power-law creep of high-entropy metallic glass

The power-law relationship between creep rate decay and time is one of the intrinsic characteristics of metallic glasses.In the current work,a La_(30)Ce_(30)Ni_(10)Al_(20)Co_(10) high-entropy metallic glass was selected as the model alloy to test the influences of physical aging and cyclic loading on the power-law creep mechanism,which was probed by the dynamic mechanical analysis in terms of the stochastic activation,and contiguous interplay and permeation of shear transformation zones.It is demonstrated that a notable discrepancy appears between thermal treatment and mechanical treatment on the power-law creep mechanism of this high-entropy metallic glass.On the one hand,physical aging below the glass transition temperature introduces the annihilation of potential shear transformation zones which contribute to creep.On the other hand,cyclic loading can tailor the“forward”jump operations competing with the“backward”ones of shear transformation zones by controlling the interval time(recovery time).The current research offers a new pathway towards understanding the creep mechanism of high-entropy metallic glasses.

环磷腺苷葡胺治疗老年慢性充血性心力衰竭临床观察

目的观察环磷腺苷葡胺（MCA）治疗老年慢性充血性心力衰竭（CHF）的临床效果。方法将46例CHF患者完全随机分为2组：对照组21例，采用常规抗心力衰竭治疗；治疗组25例，在常规治疗的基础上，将MCA120mg加入5％葡萄糖250ml静脉滴注，1次／d，14d为1个疗程。观察治疗前、后2组左心室舒张末期内径（LVDd）、左心室射血分数（LVEF）、心输出量、外周血中心钠肽和C反应蛋白水平及临床效果。结果2组患者治疗14d后，LVEF、心输出量均有所上升，LVDd和外周血心钠肽、C反应蛋白水平明显下降，而治疗组各项拮抗较对照组改善更为明显（均P〈0．05）；2组心功能较治疗前均有所改善，而治疗组总有效率可达96．0％（24／25），明显高于对照组的85．7％（18／21），其差异有统计学意义（P〈0．05）。结论环磷腺苷葡胺治疗CHF安全、有效，可有效改善心功能、提高生活质量，值得临床上推广。