From 2D to 4D: correlative imaging and modelling for next-generation automotive lithium-ion batteries

从 2D 到 4D：下一代汽车锂离子电池的相关成像和建模

• 批准号: EP/X000702/1
• 负责人: Xuekun Lu
• 金额: $ 57.16万
• 依托单位: Queen Mary University of London
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=EP%2FX000702%2F1
• 关键词: 2D; 4D; correlative; imaging; modelling

The Department for Transport of UK government announced to ban petrol and diesel vehicles by 2030 to facilitate Net Zero strategy. Being a major part of transportation electrification, the electric vehicle (EV) market is growing quickly; there are 190,727 new registrations of pure-EVs in 2021, 76.3% increase compared to 2020. Despite such success, the driving range and fast charge capability of EVs are recognised as predominant factors limiting further market penetration. Unfortunately, the physics of these requirements results in a trade-off of the lithium-ion battery design strategy. For instance, cells with high energy density provide maximum range but cannot deliver fast charging, because thicker electrodes suffer more acutely from the concentration polarisation across the electrode due to the slow ionic transport. Likewise, cells with high power density are capable of fast charging, but suffer from low mileage. More impetus in fundamental studies on physical processes of battery and the interplay between microstructure and performance are needed to eliminate range anxiety and charge-time trauma of EVs.Graphite/silicon composite electrode is regarded as one of the most promising candidates for next-generation automotive LiBs due to its high energy density. However, it suffers from the major drawbacks such as (1) volume expansion, cracking and pulverization of Si particles; (2) fast decay of capacity due to side reactions, consuming electrolyte rapidly. There is great potential to mitigate the degradation mechanisms by improved compositional and structural design based on better understanding of the ambiguous synergistic effect between the two types of particles. Moreover, lithium plating on the graphitic negative electrode is regarded as the foremost safety concern restricting the fast charge capability, leading to the consumption of lithium, electrolyte decomposition, formation of lithium dendrite and even thermal runaway. Therefore, it is critical to suppress lithium plating employing electrode design, manufacturing and rational protocols to address the longstanding challenge of battery fast charging.In this project, we aim to develop scalable and widely applicable innovations to facilitate the advancement of battery technologies for transport electrification. Correlative in operando experiment coupling the chemical, structure, crystallographic and electrochemical information from 2D to 4D will be conducted to elucidate the failure mechanisms of the graphite/Si composite electrode at the micrometer scale, particularly the synergistic dynamics of charge transfer, lithiation and deformation. Structural evolution is characterised as a function of SOC, C-rates and Si content, and linked to the capacity decay. Advanced 3D microstructure-resolved electro-chemo-mechanical model will be developed to analyse the performance limiting mechanisms, the impact of microstructural evolution on the reaction heterogeneities and predict the cycle life; in operando experiment and 3D microstructure-resolved phase field modelling will be employed to reveal the interplay between 3D microstructure of the electrode with the phase separation phenomenon, spatial dynamics of lithiation and plating. In addition, the physical processes of the relaxation behaviour, such as lithium exchange and redistribution will be elucidated by the 3D model, which will provide valuable guidelines for the refinement of fast charge protocols in terms of the timing and period of the rest steps. Finally, building on the insights of the study above, graphite/Si composite electrodes with novel structures will be fabricated, aiming to achieve at least 280 Wh kg-1 at the cell level with 20 mins charging for 50% of the capacity, corresponding to 15% increase in energy density and over 30% decrease of charging time compared to the commercial cells; an advanced physics-based fast charge protocol will be delivered to mitigate the plating risk and capacity fade.

英国政府交通部宣布，到2030年禁止汽油和柴油汽车，以促进净零排放战略。作为交通电气化的重要组成部分，电动汽车（EV）市场增长迅速; 2021年纯电动汽车新注册量为190，727辆，较2020年增长76. 3%。尽管取得了这样的成功，但电动汽车的续驶里程和快速充电能力被认为是限制进一步市场渗透的主要因素。不幸的是，这些要求的物理特性导致了锂离子电池设计策略的折衷。例如，具有高能量密度的电池提供最大范围，但不能提供快速充电，因为较厚的电极由于缓慢的离子传输而更剧烈地遭受跨电极的浓度极化。同样地，具有高功率密度的电池能够快速充电，但是遭受低里程。为了消除电动汽车的续航里程焦虑和充电时间创伤，需要对电池的物理过程以及微观结构与性能之间的相互作用进行更多的基础研究。石墨/硅复合电极由于其高能量密度而被认为是下一代汽车锂电池最有前途的候选者之一。然而，其具有主要缺点，例如（1）Si颗粒的体积膨胀、破裂和粉化;（2）由于副反应导致的容量快速衰减，快速消耗电解质。有很大的潜力，以减轻降解机制，通过改进的组成和结构设计的基础上更好地了解这两种类型的颗粒之间的模糊的协同效应。此外，石墨负极上的锂电镀被认为是限制快速充电能力的首要安全问题，导致锂的消耗、电解质分解、锂枝晶的形成以及甚至热失控。因此，通过电极设计、制造和合理的方案来抑制锂电镀，以解决电池快速充电的长期挑战至关重要。在本项目中，我们的目标是开发可扩展和广泛适用的创新，以促进运输电气化电池技术的进步。通过将二维到四维的化学、结构、晶体学和电化学信息耦合起来的相关实验，在微米尺度上研究了石墨/硅复合电极的失效机理，特别是电荷转移、锂化和变形的协同动力学。结构演变的特点是作为一个功能的SOC，C-率和Si含量，并链接到容量衰减。将开发先进的三维微观结构分辨电化学机械模型，以分析性能限制机制、微观结构演变对反应不均匀性的影响，并预测循环寿命;在操作实验中，将采用3D显微结构分辨相场建模来揭示电极的3D显微结构与相分离现象之间的相互作用，锂化和电镀的空间动力学。此外，3D模型将阐明弛豫行为的物理过程，如锂交换和再分布，这将为快速充电协议在休息步骤的时间和周期方面的改进提供有价值的指导。最后，在上述研究的基础上，将制造具有新型结构的石墨/Si复合电极，目标是在电池水平上实现至少280 Wh kg-1，20分钟充电50%的容量，与商业电池相比，能量密度增加15%，充电时间减少30%以上;将提供先进的基于物理的快速充电协议，以减轻电镀风险和容量衰减。

项目成果

Multiscale dynamics of charging and plating in graphite electrodes coupling operando microscopy and phase-field modelling.

• DOI: 10.1038/s41467-023-40574-6
• 发表时间: 2023-08-24
• 期刊: NATURE COMMUNICATIONS
• 影响因子: 16.6
• 作者: Lu, Xuekun;Lagnoni, Marco;Bertei, Antonio;Das, Supratim;Owen, Rhodri E.;Li, Qi;O'Regan, Kieran;Wade, Aaron;Finegan, Donal P.;Kendrick, Emma;Bazant, Martin Z.;Brett, Dan J. L.;Shearing, Paul R.
• 通讯作者: Shearing, Paul R.