Electrode-coated alumina separators for lithium-ion batteries - effect of particle size and distribution of alumina powders

Kanhere, Narayan Vishnu; Rafiz, Kishen; Sharma, Gaurav; Sun, Zhe; Yi, Jin; Lin, Yun-Huin

doi:10.1016/j.powtec.2019.05.007

Cited by 16 publications

(11 citation statements)

References 22 publications

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“…Among the battery components, battery separators are primarily responsible for preventing and managing battery shorting and thermal runaway. Thermally responsive separator are engineered to collapse or expand in response to high temperatures, blocking ion‐flow to effectively shut off the cell 20,21. With the help of a third electrode, separators are able to detect a penetrating dendrite 22.…”

Section: Figurementioning

confidence: 99%

“…Thermally responsive separator are engineered to collapse or expand in response to high temperatures, blocking ion-flow to effectively shut off the cell. [20,21] With the help of a third electrode, separators are able to detect a penetrating dendrite. [22] Alternatively, mechanically robust separators can in principle block internal shorting due to lithium dendrite penetration.…”

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confidence: 99%

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Draining Over Blocking: Nano‐Composite Janus Separators for Mitigating Internal Shorting of Lithium Batteries

et al. 2020

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Catastrophic battery failure due to internal short is extremely difficult to detect and mitigate. In order to enable the next‐generation lithium‐metal batteries, a “fail safe” mechanism for internal short is highly desirable. Here, a novel separator design and approach is introduced to mitigate the effects of an internal short circuit by limiting the self‐discharge current to prevent cell temperature rise. A nano‐composite Janus separator—with a fully electronically insulating side contacting the anode and a partially electronically conductive (PEC) coating with tunable conductivity contacting the cathode—is implemented to intercept dendrites, control internal short circuit resistance, and slowly drain cell capacity. Galvanostatic cycling experiments demonstrate Li‐metal batteries with the Janus separator perform normally before shorting, which then results in a gradual increase of internal self‐discharge over >25 cycles due to PEC‐mitigated shorting. This is contrasted by a sudden voltage drop and complete failure seen with a single layer separator. Potentiostatic charging abuse tests of Li‐metal pouch cells result in dendrites completely penetrating the single‐layer separator causing high short circuit current and large cell temperature increase; conversely, negligible current and temperature rise occurs with the Janus separator where post mortem electron microscopy shows the PEC layer successfully intercepts dendrites.

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Section: Figurementioning

confidence: 99%

mentioning

confidence: 99%

Draining Over Blocking: Nano‐Composite Janus Separators for Mitigating Internal Shorting of Lithium Batteries

et al. 2020

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“…This large particle size distribution tends to maximize particle packing density. Where the large particles can form a rigid structure, and the fine active particles form the matrix and bind the large particles after sintering, which is very suitable for certain applications such as refractory materials [17] and electrode-coated for lithium-ion batteries [38]. It is worth noting that some applications like catalysis, abrasives and nanocomposites need disperse fine α-alumina particles with narrow particle size distribution [37].…”

Section: Microstructural and Morphological Characteristics Of The Recovered Aluminamentioning

confidence: 99%

Synthesis of submicronic α-alumina from local aluminum slags

ahmed

Elkolli

Hamidouche

2022

J min metall B Metall

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In this study, a high valued product submicronic ?-alumina is successfully extracted from aluminum slags generated by the local aluminum industry. The extraction technique is based on the leaching of slags by H2SO4 followed by precipitation. The coarser aluminum-rich fractions of the slags are used in this study instead of the finer oxide-rich fractions that were commonly used in previous studies. The precipitation of the leached slags by NH4OH is controlled by zetameter in order to determine the optimal precipitation pH. Then, the obtained gel showing the higher precipitation rate and the finer particle size is calcined at 1200 ?C and characterized by XRF, XRD, FTIR, SEM, EDS and laser granulometry. Even without any pretreatment of slags, the XRF analysis reveals that a high purity and high extraction efficiency of 99.2% and 93.75% respectively can be achieved just at a leaching acid concentration of 15%. XRD spectrum shows that the produced alumina is a pure a-corundum, which is confirmed by FTIR spectrum showing only the Al-O bonds. The laser granulometry shows that the recovered powder exhibit a wide particle size distribution. It is between 50 nm and 20 ?m while the average particle size (d50) is about 400 nm. SEM observations reveal that the grains are in the form of submicronic whiskers. The above characteristics allow the obtained alumina powder in this study to be used in the usual applications of alumina such as refractory, ceramic fibers, abrasive, etc. The obtained powders may assume also applications as a thermally stable substitute for the commonly used transition alumina powders, which need further investigations in future studies.

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“…欧盟 Battery 2030 +等。高能量和功率密度、高循环稳定性的锂离子电池不仅取决于优异的活性物质、电解液等材料，也与电池的制造工艺及装备息息相关 [2] 。特别是动力和储能应用需要大量的单体电池串并联成组，需要高精度保障单体电池的一致性，避免"短板效应"带来的模组容量损失和循环寿命衰减，保障电池的安全性。对于电池模块，每个单体电池承受相同电流，其电压是所有单体电池的总和，因此电池模块容量、电化学性能受限于模块内最弱的单体电池。孙逢春院士指出"电池性能不一致性使动力电池组在电动汽车上使用时，性能指标往往达不到单电池原有水平，使用寿命缩短数倍甚至十几倍" [3] 。因此，制造阶段引起的单体电池之间微小差异可能会导致电池组的整体容量、电化学性能发生重大变化。如新能源汽车、储能等需求急剧增长，全电动汽车动力电池由成百上千个锂离子单体电池组成，容量比手机高约 5000 倍，复合年增长率达到 20%以上。锂离子动力电池对制造一致性要求苛刻，通过极高的制造过程管控来满足特定容差，以保证电池的容量、内阻、寿命和安全性。 2021 年，北京汽车股份有限公司因为电池一致性问题，存在引发起火风险的严重安全隐患，一次召回 31963 辆电动汽车。锂离子电池在作为卫星的空间电源应用时，承受冲击、振动、高低温等恶劣服役环境，使用寿命需满足低轨 5~10 年、高轨 15~10 年的要求 [4] ，需要大量的冗余设计来保证电池组的使用寿命。锂离子电池制造过程复杂，可以分为前段的极片制造、中段的电芯装配和后段的化成分容检测 [5] 。极片制造是锂离子电池最核心的制造过程，包括制浆、涂布和辊压三大关键工序，通过将正负极活性物质、导电剂、黏结剂等制成浆料，涂覆在铜/铝箔上，干燥、辊压压实后得到正负电极，构成电化学反应载体和整个电池的核心。电极制造过程影响着正负电极的孔隙率、厚度、密度，以及导电网络、黏结网络等微结构，很大程度上决定着锂离子电池性能 [6] 离子电导率等，均会显著影响其黏度 [8,9] 、分散状态 [10,11] 与电化学特性 [12,13] 。如 Ouyang 等人 [14] 研究了固含量对 LiNi 0.8 Co 0.15 Al 0.05 O 2 正极浆料流变特性和微观结构的影响，结果表明长链结构的 PVDF 分子会吸附在固体颗粒表面，其桥接功能会随着固含量而变化，当低于最佳固含量(<63.9%) 时，颗粒间形成弱絮凝网络结构，颗粒易发生沉降；当超过最佳固含量时(＞66.3%)，浆料会产生过大的屈服应力，固体颗粒间不发生直接接触，分散均匀性降低(图 2a)。Kwon 等人 [15] 研究发现，与球状石墨(比表面积为 0.95 m 2 /g)相比，片状石墨(比表面积为 16 m 2 /g)能提供更大的表面积与 LiCoO 2 颗粒接触，电极表现出更优异的循环伏安特性，同时在浆料中具有更好的分散性 (图 2b)。此外，采用小粒径乃至纳米级尺寸的活性颗粒或碳纳米管、石墨烯等作为导电剂，可显著提升锂离子电池的能量密度、倍率等性能 [16,17] 。但小粒径颗粒会大幅增加浆料黏度，需要更强的剪切作用实现均匀分散，同时具有高表面积与表面能的纳米颗粒还存在促进电解质分解、团聚严重与低堆积密度的风险，导致初始库伦效率低、接触电阻大以及电极体积能量密度差 [18,19] 。因此，设计组分比例、粒径适中的材料体系是获得流变特性优异、稳定均匀电极浆料的前提。 A c c e p t e d https://engine.scichina.com/doi/10.1360/TB-2021-1069 图 2 制浆过程中的电极微结构演化. (a)不同固含量下浆料中颗粒与 PVDF 相互作用机制 [14] ；(b)含片状与球状炭黑的 LiCoO 2 电极粉末球磨过程 [15] ；(c)不同混料顺序制备的电极干燥前后微结构变化 [27] ；(d)颗粒形态、导电面面积比与混合参数之间的关系 [28] Figure 2 Electrode microstructure evolution during slurry mixing process.…”

Section: 定科技专项，包括我国《新能源汽车产业发展规划(2021-2035 年)》，美国能源部的 Battery 500，unclassified

Microstructure evolutions in lithium ion battery electrode manufacturing

Li¹,

Zhang²,

Wang³

et al. 2021

Chin. Sci. Bull.

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Since its commercialization in the 1990s, the lithium-ion battery has been a huge success in the energy industry owing to its high energy density and long cycle life. They have been used in national strategic fields, such as satellites and unmanned aircraft, to promote a remarkable leap forward in new energy, new energy vehicles, and other emerging industries. Therefore, the development of lithium-ion batteries is a strategic high ground for competition among countries worldwide.The development and widespread use of lithium-ion batteries is driven by their high energy/power density, long cycle life, and low cost, which requires battery material innovation as well as advancements in manufacturing processes and equipment technology. Particularly, the power and energy storage applications require numbers of battery cells connected in series or parallel. High precision is required to ensure the consistency of the battery cell, to avoid module capacity loss and cycle life attenuation owing to the "shortboard effect," and to ensure battery safety. Electrode manufacturing, which is the first critical process of lithium-ion battery production, consists of three critical steps: mixing, coating, and rolling. The positive and negative electrode active materials, conductive agents, binders and solvents are mixed into slurry and coated on copper or aluminum foil. The positive/negative electrodes, which constitute the electrochemical reaction carrier and the battery's core, are obtained after drying and roller compaction. The porous and multi-component electrode microstructure evolves and is constructed in a complex way during electrode manufacturing. The proportion of electrode slurry, mixing order, coating method, drying strategy, and rolling process can considerably affect the evolution of electrode microstructure, such as pore structure, active particle distribution and, conductive/bonding network. It also influences the lithium-ion battery's electrochemical performance. Despite tremendous advances in high-energy-density materials, research on lithium-ion battery manufacturing lags, resulting a large gap between laboratory and production scales.This requires an in-depth understanding of the manufacturing and the relationship between electrode microstructure evolution and battery performance.The advancement and application of cutting-edge slurry mixing, coating, and calendering technologies in electrode manufacturing are thoroughly reviewed in this paper. The evolution of electrode microstructure during manufacturing, in particular, and its impact on the battery's electrochemical performance, are discussed in detail. Then, various novel electrode manufacturing techniques are summarized in terms of their significance and challenges, covering the innovations based on the current process (aqueous processing, simultaneous double-sided slot coating, multilayer co-coating and, multistage drying), dry processing (electron beam and ultraviolet curing forming, electrostatic dry-powder coating), threedimensional printing, template-ba...

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Electrode-coated alumina separators for lithium-ion batteries - effect of particle size and distribution of alumina powders

Cited by 16 publications

References 22 publications

Draining Over Blocking: Nano‐Composite Janus Separators for Mitigating Internal Shorting of Lithium Batteries

Draining Over Blocking: Nano‐Composite Janus Separators for Mitigating Internal Shorting of Lithium Batteries

Synthesis of submicronic α-alumina from local aluminum slags

Microstructure evolutions in lithium ion battery electrode manufacturing

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