Revealing the Intrinsic Uneven Electrochemical Reactions of Li Metal Anode in Ah-Level Laminated Pouch Cells

The uneven electrochemical reactions of lithium (Li) metal anode is one of the main reasons that hinder its application in rechargeable high energy density batteries. Great progress has been achieved in homogenizing electrochemical reactions of Li metal anode in lab-scale coin cells, however, it cannot be directly applied to pouch cells, where undesirable defects or side reactions are significantly aggravated. With carbonate electrolyte, multi-layered negative and positive electrodes (8 × 11 cm), 1.2 Ah sulfurized polyacrylonitrile (SPAN)||Li pouch cell lost all its capacity after 40 cycles under a current of 600 mA, although its counterpart with coin cell configuration showed much higher capacity retention of 94% under the same test condition. Severe corrosion with uneven, porous, dendritic Li deposits is observed for pristine Li electrode in a pouch cell, especially in the near-tap and the central regions with close connection with the current collector due to the locally amplified current densities. In contrast, Li/Li–Sn alloy composite electrode displays uniform and dense Li plating behavior over the entire test area with significantly suppressed parasitic reactions and gas evolution. As such, a 1.2 Ah SPAN||Li/Li–Sn cell displays much higher capacity retention than SPAN||Li cell (87% for 100 cycles vs. 0 for 40 cycles).     

Efficient Synergism of Chemisorption and Wackenroder Reaction via Heterostructured La2O3-Ti3C2Tx -Embedded Carbon Nanofiber for High-Energy Lithium-Sulfur Pouch Cells

Lithium-sulfur (Li-S) batteries have been regarded as promising next-generation energy storage systems due to their high energy density and low cost, but their practical application is hindered by inferior long-cycle stability caused by the severe shuttle effect of lithium polysulfides (LiPSs) and sluggish reaction kinetics. This study reports a La₂O₃-MXene heterostructure embedded in carbon nanofiber (CNF) (denoted as La₂O₃-MXene@CNF) as a sulfur (S) host to address the above issues. The unique features of this heterostructure endow the sulfur host with synergistic catalysis during the charging and discharging processes. The strong adsorption ability provided by the La₂O₃ domain can capture sufficient LiPSs for the subsequent catalytic conversion, and the insoluble thiosulfate intermediate produced by hydroxyl terminal groups on the surface of MXene greatly promotes the rapid conversion of LiPSs to Li₂S via a “Wackenroder reaction.” Therefore, the S cathode with La₂O₃-MXene@CNF (La₂O₃-MXene@CNF/S) exhibits excellent cycling stability with a low capacity fading rate of 0.031% over 1000 cycles and a high capacity of 857.9 mAh g⁻¹ under extremely high sulfur loadings. Furthermore, a 5 Ah-level pouch cell is successfully assembled for stable cycling, which delivers a high specific energy of 341.6 Wh kg⁻¹ with a low electrolyte/sulfur ratio (E/S ratio).     

基于热成像的软包锂电池导热系数测试方法

为给软包锂电池热设计提供准确的导热系数值,提出了一种基于热成像技术的测试方法。通过热像仪记录电池表面温度场的演变数据,可同时反演电池的纵向和面向导热系数,避免了传统接触式表面测温引入的不确定因素。测试了多块不同规格的三元聚合物软包锂电池样品,并对其中一种样品进行了稳态法导热系数测量作为参考。结果显示,纵向和面向导热系数测试的相对标准差均在3%以内,纵向导热系数的测试结果与稳态法测量结果的相对偏差为3.1%,表明该方法具有较高的可靠性,可为电池的热设计提供参考。     

方便面生产线后段自动化改造

方便面生产线后段应用自动投包机、叠袋机、自动裹包式纸箱装箱机等自动化设备替代人工损伤,可大大提高整条生产线的综合水平,降低生产成本,每条１２万包／班的生产线每年可节约１００万元左右。     

Angioarchitecture of squamous cell carcinoma from hamster buccal pouch: a scanning electron microscopy study

Tumoral angiogenesis has been widely studied by histochemical analysis but little has been done regarding morphology of these new vessels. The objective of this study was to perform a qualitative analysis of the angiogenic response to chemical induction with dimethylbenzanthracene (DMBA) and carbamide peroxide of squamous cell carcinoma in pouches of Syrian hamsters after different periods of treatment. Twenty‐four Syrian golden hamsters, divided into three groups of eight animals each, had their right jugal pouches treated with a 5% DMBA solution three times a week and a 10% carbamide peroxide two times a week for 55, 70 and 90 days. The left pouch was considered the control. After tumor induction, five animals in each group had their pouches prepared for analysis under scanning electron microscopy and three animals for analysis under light microscopy. The control pouches showed a vascular system composed by few main vessels running parallel to the longest axis of the pouch with some branches. In the pouches submitted to tumor induction, a well‐differentiated squamous cell carcinoma was present since 55 days induction in all samples. The new vascular system showed the presence of many tortuous vessels and the majority of them were veins and capillaries. Terminal loops were extremely sinuous adopting a glomerular or corkscrew shape. These tumor vessels are different from normal vessels, presenting irregular diameters, outpouchings and constrictions. Angiogenesis of sprouting and intussusceptive kind could be identified in the tumor pouches, and they were more frequent as the tumor developed. SCANNING 31: 188–194, 2009. © 2009 Wiley Periodicals, Inc.     

车用大尺寸软包锂离子电池在高低温升 工况下的生热率测定

提出了一种电动汽车用大尺寸软包锂离子电池的生热率测量方法——热补偿法,研究了电池生热率与工作电流、温度之间的曲线关系,其有效性得到了常规热流计法的验证,最后结合这两种方法研究了电池在高、低温升工况下的生热特性。研究结果表明,基于热补偿法的电池生热率平均测算偏差低于5.6%;电池的生热率随工作电流的增大而增大,二者呈二次非线性关系;电池在高温升工况下的生热率随放电深度呈先降后升趋势,形似U型曲线;电池在低温升工况下的平均生热率较其在高温升工况下高约13.7%。提出的热补偿法具有精度高、成本低、简便灵活等优势,研究成果可为大尺寸软包锂离子电池的热模型建立和热管理系统设计给予指导。     

浸泡方式对食品接触材料高锰酸钾消耗量影响的研究

目的 研究全浸没法、袋装法、测试池法和填充法四种不同的浸泡方式对各种食品接触材料高锰酸钾消耗量的影响。方法 测试方法参照GB/T 5009.60-2003《食品包装用聚乙烯、聚苯乙烯、聚丙烯成型品卫生标准的分析方法》中测定高锰酸钾消耗量的方法。结果 密胺餐具采用填充法比全浸没法和测试池法所消耗的高锰酸钾量高。复合膜产品采用全浸没法所消耗的高锰酸钾量是袋装法的2倍多。纸浆类产品采用填充法所消耗的高锰酸钾量比全浸没法所消耗的高锰酸钾量大。结论 扁平容器类餐具适合采用测试池法; 容积较小的容器餐具类适合采用全浸没法; 薄膜/袋包装类产品适合采用袋装法和全浸没法, 其中复合薄膜类产品适合袋装法, 纸浆类产品则适合全浸没法。     

熟制玉米的蒸煮袋包装设计

将高温蒸煮技术与熟制玉米的包装相结合,围绕蒸煮袋的结构、选材及材料厚度的确定等内容对熟制玉米进行蒸煮包装设计。根据被包装玉米的尺寸及性能要求,设计该蒸煮包装袋为四面封口的直立袋结构,包装尺寸为24.5 cm×12.5 cm,材料结构为PET15/PA15/PVDC7/CPP50;并根据熟制玉米的最大允许透水量、设计所用材料的透湿系数和厚度对材料进行保质期验算。通过对所设计蒸煮袋的热封试验,确定了其最佳热封参数:热封压力为50~100 kPa,热封温度为135~145℃,热封时间为2~3 s。     

软包装主食罐头杀菌工艺研究

对软包装主食罐头的杀菌工艺进行研究,分析在不同杀菌温度和时间条件下食品中心温度及F值的变化,确定最佳杀菌方式为双峰高温杀菌,杀菌参数为80℃、5min,110℃、5min,121℃、12min,125℃、(30+30)s,峰底113℃,该杀菌工艺能够有效降低软包装主食罐头的杀菌强度,杀菌后的产品大大降低了因高温产生的后熟蒸馏味,大幅延长了保质期,最终产品品质显著提高。     

3.0 V-class film-type lithium primary battery with highly improved energy density

Lithium metal is used as an anode material in a 3.0 V-class film-type MnO₂||Li primary battery to increase the operating voltage and discharge capacity for application to active sensor tags of a radio-frequency identification system. A 20-μm thick lithium layer deposited homogeneously on a copper foil is prepared for the purpose of controlling the efficient utilization and lithium handling. A plasticized gel polymer electrolyte filled with SiO₂ particles is also used to enhance the electrochemical stability and safety of the battery. A lithium primary battery with a lithium anode and a nonaqueous electrolyte is fabricated for the first time in the form of a film with a newly designed Nylon 6/Al/polypropylene pouch for perfect shielding. The fabricated 3.0 V-class film-type lithium primary battery passes several safety tests and achieves a discharge capacity and an energy density of more than 9 mAh cm⁻² and 470 Wh L⁻¹, respectively.