【期刊】热点专题 | 储能材料和器件的多尺度计算与先进表征 | CPB | 自由微信

【期刊】热点专题 | 储能材料和器件的多尺度计算与先进表征 | CPB

CPB 蔻享学术 2021-04-26

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为了展现国内外在储能材料和器件多尺度计算与先进表征领域的代表性研究成果，"Chinese Physics B"(CPB)编辑部邀请李泓、施思齐、禹习谦三位老师作为客座编辑，组织了“Advanced calculation & characterization of energy storage materials & devices at multiple scale”专题，至2020年第6期已经全部正式出版，敬请关注！

编者按

客座编辑

李泓 中国科学院物理研究所

施思齐 上海大学

禹习谦 中国科学院物理研究所

锂离子电池作为一种性能优越的新型可充放电池已经在移动通信、手提式计算机和电动汽车等诸多领域获得广泛应用。然而，锂离子电池也面临着其性能需要全面提升、应用领域需进一步拓宽的强劲需求。因此，亟需精确认识锂离子电池在不同时间-空间尺度上复杂的构型关系，全面理解电池在服役过程中的失效机制。尤其是近三十年的应用实践经验表明，实现锂离子电池的性能提升不仅取决于先进材料的发展，也依赖于电池设计、制造与管理水平的提升。

本次在CPB组织的“储能材料和器件的多尺度计算与先进表征”专题，研究内容可以大致划分为如下四个方面:(1) 采用高通量第一性原理计算并结合力学-电化学耦合方程的锂离子输运机理研究及材料筛选；(2)利用电子显微学、X射线和中子实验技术研究不同空间尺度下电池材料结构与电池性能之间的关联；(3)通过分析锂离子电池电极尺度断裂行为的理论、模拟和实验研究现状，探究电极尺度断裂对电池性能的影响机理及相关的科学问题；(4)以过程系统工程的建模、仿真与优化视角，全面综述基于模型的锂离子电池多尺度优化设计与管理方法，并展望未来发展方向。希望这个专题能够为加强国内外储能材料和器件多尺度计算与先进表征领域的学术交流，并推动高性能储能材料和器件的研发做出贡献。

REVIEWS

Neutron-based characterization techniques for lithium-ion battery research

Enyue Zhao(赵恩岳), Zhi-Gang Zhang(张志刚), Xiyang Li(李西阳), Lunhua He(何伦华), Xiqian Yu(禹习谦), Hong Li(李泓), Fangwei Wang(王芳卫)

Chin. Phys. B, 2020, 29 (1): 018201

Abstract: During the past decades, Li-ion batteries have been one of the most important energy storage devices. Large-scale energy storage requires Li-ion batteries which possess high energy density, low cost, and high safety. Other than advanced battery materials, in-depth understanding of the intrinsic mechanism correlated with cell reaction is also essential for the development of high-performance Li-ion battery. Advanced characterization techniques, especially neutron-based techniques, have greatly promoted Li-ion battery researches. In this review, the characteristics or capabilities of various neutron-based characterization techniques, including elastic neutron scattering, quasi-elastic neutron scattering, neutron imaging, and inelastic neutron scattering, for the related Li-ion-battery researches are summarized. The design of in-situ/operando environment is also discussed. The comprehensive survey on neutron-based characterizations for mechanism understanding will provide guidance for the further study of high-performance Li-ion batteries.

Review on electrode-level fracture in lithium-ion batteries

Bo Lu(吕浡), Chengqiang Ning(宁成强), Dingxin Shi(史定鑫), Yanfei Zhao(赵炎翡), Junqian Zhang(张俊乾)

Chin. Phys. B, 2020, 29 (2): 026201

Abstract: Fracture occurred in electrodes of the lithium-ion battery compromises the integrity of the electrode structure and would exert bad influence on the cell performance and cell safety. Mechanisms of the electrode-level fracture and how this fracture would affect the electrochemical performance of the battery are of great importance for comprehending and preventing its occurrence. Fracture occurring at the electrode level is complex, since it may involve fractures in or between different components of the electrode. In this review, three typical types of electrode-level fractures are discussed: the fracture of the active layer, the interfacial delamination, and the fracture of metallic foils (including the current collector and the lithium metal electrode). The crack in the active layer can serve as an effective indicator of degradation of the electrochemical performance. Interfacial delamination usually follows the fracture of the active layer and is detrimental to the cell capacity. Fracture of the current collector impacts cell safety directly. Experimental methods and modeling results of these three types of fractures are concluded. Reasonable explanations on how these electrode-level fractures affect the electrochemical performance are sorted out. Challenges and unsettled issues of investigating these fracture problems are brought up. It is noted that the state-of-the-art studies included in this review mainly focus on experimental observations and theoretical modeling of the typical mechanical damages. However, quantitative investigations on the relationship between the electrochemical performance and the electrode-level fracture are insufficient. To further understand fractures in a multi-scale and multi-physical way, advancing development of the cross discipline between mechanics and electrochemistry is badly needed.

Advanced characterization and calculation methods for rechargeable battery materials in multiple scales

Xin-Yan Li(李欣岩), Su-Ting Weng(翁素婷), Lin Gu(谷林)

Chin. Phys. B, 2020, 29 (2): 028801

Abstract: The structure-activity relationship of functional materials is an everlasting and desirable research question for material science researchers, where characterization and calculation tools are the keys to deciphering this intricate relationship. Here, we choose rechargeable battery materials as an example and introduce the most representative advanced characterization and calculation methods in four different scales: real space, energy, momentum space, and time. Current research methods to study battery material structure, energy level transition, dispersion relations of phonons and electrons, and time-resolved evolution are reviewed. From different views, various expression forms of structure and electronic structure are presented to understand the reaction processes and electrochemical mechanisms comprehensively in battery systems. According to the summary of the present battery research, the challenges and perspectives of advanced characterization and calculation techniques for the field of rechargeable batteries are further discussed.

Pair distribution function analysis: Fundamentals and application to battery materials

Xuelong Wang(王雪龙), Sha Tan(谭莎), Xiao-Qing Yang(杨晓青), Enyuan Hu(胡恩源)

Chin. Phys. B, 2020, 29 (2): 028802

Abstract: Battery materials are of vital importance in powering a clean and sustainable society. Improving their performance relies on a clear and fundamental understanding of their properties, in particular, structural properties. Pair distribution function (PDF) analysis, which takes into account both Bragg scattering and diffuse scattering, can probe structures of both crystalline and amorphous phases in battery materials. This review first introduces the principle of PDF, followed by its application in battery materials. It shows that PDF is an effective tool in studying a series of key scientific topics in battery materials. They range from local ordering, nano-phase quantification, anion redox reaction, to lithium storage mechanism, and so on.

Failure analysis with a focus on thermal aspect towards developing safer Na-ion batteries

Yuqi Li(李钰琦), Yaxiang Lu(陆雅翔), Liquan Chen(陈立泉), Yong-Sheng Hu(胡勇胜)

Chin. Phys. B, 2020, 29 (4): 048201

Abstract: Safety requirements stimulate Na-based batteries to evolve from high-temperature Na-S batteries to room-temperature Na-ion batteries (NIBs). Even so, NIBs may still cause thermal runaway due to the external unexpected accidents and internal high activity of electrodes or electrolytes, which has not been comprehensively summarized yet. In this review, we summarize the significant advances about the failure mechanisms and related strategies to build safer NIBs from the selection of electrodes, electrolytes and the construction of electrode/electrolyte interfaces. Considering the safety risk, the thermal behaviors are emphasized which will deepen the understanding of thermal stability of different NIBs and accelerate the exploitation of safe NIBs.

Design and management of lithium-ion batteries: A perspective from modeling, simulation, and optimization

Qian-Kun Wang(王乾坤), Jia-Ni Shen(沈佳妮), Yi-Jun He(贺益君), Zi-Feng Ma(马紫峰)

Chin. Phys. B, 2020, 29 (6): 068201

Abstract: Although the lithium-ion batteries (LIBs) have been increasingly applied in consumer electronics, electric vehicles, and smart grid, they still face great challenges from the continuously improving requirements of energy density, power density, service life, and safety. To solve these issues, various studies have been conducted surrounding the battery design and management methods in recent decades. In the hope of providing some inspirations to the research in this field, the state of the art of design and management methods for LIBs are reviewed here from the perspective of process systems engineering. First, different types of battery models are summarized extensively, including electrical model and multi-physics coupled model, and the parameter identification methods are introduced correspondingly. Next, the model based battery design methods are reviewed briefly on three different scales, namely, electrode scale, cell scale, and pack scale. Then, the battery model based battery management methods, especially the state estimation methods with different model types are thoroughly compared. The key science and technology challenges for the development of battery systems engineering are clarified finally.

ARTICLES

Photon-in/photon-out endstation for studies of energy materials at beamline 02B02 of Shanghai Synchrotron Radiation Facility

Guoxi Ren(任国玺), Nian Zhang(张念), Xuefei Feng(冯雪飞), Hui Zhang(章辉), Pengfei Yu(于鹏飞), Shun Zheng(郑顺), Deng Zhou(周櫈), Zongwang Tian(田宗旺), Xiaosong Liu(刘啸嵩)

Chin. Phys. B, 2020, 29 (1): 016101

Abstract: A new photon-in/photon-out endstation at beamline 02B02 of the Shanghai Synchrotron Radiation Facility for studying the electronic structure of energy materials has been constructed and fully opened to users. The endstation has the capability to perform soft x-ray absorption spectroscopy in total electron yield and total fluorescence yield modes simultaneously. The photon energy ranges from 40 eV to 2000 eV covering the K-edge of most low Z-elements and the L-edge of 3d transition-metals. The new self-designed channeltron detector allows us to achieve good fluorescence signals at the low photon flux. In addition, we synchronously collect the signals of a standard reference sample and a gold mesh on the upstream to calibrate the photon energy and monitor the beam fluctuation, respectively. In order to cross the pressure gap, in situ gas and liquid cells for soft x-ray absorption spectroscopy are developed to study the samples under realistic working conditions.

Revealing the inhomogeneous surface chemistry on the spherical layered oxide polycrystalline cathode particles

Zhi-Sen Jiang(蒋之森), Shao-Feng Li(李少锋), Zheng-Rui Xu(许正瑞), Dennis Nordlund, Hendrik Ohldag, Piero Pianetta, Jun-Sik Lee, Feng Lin(林锋), Yi-Jin Liu(刘宜晋)

Chin. Phys. B, 2020, 29 (2): 026103

Abstract: The hierarchical structure of the composite cathodes brings in significant chemical complexity related to the interfaces, such as cathode electrolyte interphase. These interfaces account for only a small fraction of the volume and mass, they could, however, have profound impacts on the cell-level electrochemistry. As the investigation of these interfaces becomes a crucial topic in the battery research, there is a need to properly study the surface chemistry, particularly to eliminate the biased, incomplete characterization provided by techniques that assume the homogeneous surface chemistry. Herein, we utilize nano-resolution spatially-resolved x-ray spectroscopic tools to probe the heterogeneity of the surface chemistry on LiNi0.8Mn0.1Co0.1O2 layered cathode secondary particles. Informed by the nano-resolution mapping of the Ni valance state, which serves as a measurement of the local surface chemistry, we construct a conceptual model to elucidate the electrochemical consequence of the inhomogeneous local impedance over the particle surface. Going beyond the implication in battery science, our work highlights a balance between the high-resolution probing the local chemistry and the statistical representativeness, which is particularly vital in the study of the highly complex material systems.

Computational screening of doping schemes forLiTi2(PO4)3 as cathode coating materials

Yu-Qi Wang(王宇琦), Xiao-Rui Sun(孙晓瑞), Rui-Juan Xiao(肖睿娟), Li-Quan Chen(陈立泉)

Chin. Phys. B, 2020, 29 (3): 038202

Abstract: In all-solid-state lithium batteries, the impedance at the cathode/electrolyte interface shows close relationship with the cycle performance. Cathode coatings are helpful to reduce the impedance and increase the stability at the interface effectively. LiTi2(PO4)3 (LTP), a fast ion conductor with high ionic conductivity approaching 10-3 S·cm-1, is adopted as the coating materials in this study. The crystal and electronic structures, as well as the Li+ ion migration properties are evaluated for LTP and its doped derivatives based on density functional theory (DFT) and bond valence (BV) method. Substituting part of Ti sites with element Mn, Fe, or Mg in LTP can improve the electronic conductivity of LTP while does not decrease its high ionic conductivity. In this way, the coating materials with both high ionic conductivities and electronic conductivities can be prepared for all-solid-state lithium batteries to improve the ion and electron transport properties at the interface.

Comparative calculation on Li⁺ solvation in common organic electrolyte solvents for lithium ion batteries

Qi Liu(刘琦), Feng Wu(吴锋), Daobin Mu(穆道斌), Borong Wu(吴伯荣)

Chin. Phys. B, 2020, 29 (4): 048202

Abstract: It is important for the electrolytes to maintain and enhance the lithium ion battery electrochemical performance, and solvation of Li⁺ is a key parameter for the property of the electrolytes. The comparative study on Li⁺ solvation structures, energy, enthalpy, Gibbs free energy, infrared and Raman spectra in common organic electrolyte solvents is completed by density functional theory (DFT) method. The solvation reaction energy results suggest that the Li⁺ solvation priority order is propylene carbonate (PC) > ethylene carbonate (EC) > ethyl methyl carbonate (EMC) > diethyl carbonate (DEC) > tetrahydrofuran (THF) > dimethyl carbonate (DMC) > 1,3-dioxolane (DOL) > dimethoxyethane (DME) to form 5sol-Li^⁺. It is also indicated that the most innermost solvation shell compounds formations by stepwise spontaneous solvation reaction are four cyclic solvent molecules and three linear solvent molecules combining one Li⁺ forming 4sol-Li⁺ and 3sol-Li⁺, respectively, at room temperature. Besides, the vibration peaks for C=O and C-O bonds in carbonate ester solvents-Li⁺ compounds shift to lower frequency and higher frequency, respectively, when the Li⁺ concentration increases in the solvation compounds. All Li-O stretching vibration peaks shift to higher frequency until forming 2solvent-Li⁺complexes, and C-H stretching also shifts to higher frequency except for nDME-Li⁺ solvation compounds. The Raman spectrum is more agile to characterize C-H vibrations and IR is agile to C=O, C-O, and Li-O vibrations for Li⁺ solvation compounds.

Influence of fluoroethylene carbonate on the solid electrolyte interphase of silicon anode for Li-ion batteries: A scanning force spectroscopy study

Jieyun Zheng(郑杰允), Jialiang Liu(刘家亮), Suijun Wang(王绥军), Fei Luo(罗飞), Liubin Ben(贲留斌), Hong Li(李泓)

Chin. Phys. B, 2020, 29 (4): 048203

Abstract: Silicon is an important high capacity anode material for the next generation Li-ion batteries. The electrochemical performances of the Si anode are influenced strongly by the properties of the solid electrolyte interphase (SEI). It is well known that the addition of flouroethylene carbonate (FEC) in the carbonate electrolyte is helpful to improve the cyclic performance of the Si anode. The possible origin is suggested to relate to the modification of the SEI. However, detailed information is still absent. In this work, the structural and mechanical properties of the SEI on Si thin film anode in the ethylene-carbonate-based (EC-based) and FEC-based electrolytes at different discharging and charging states have been investigated using a scanning atomic force microscopy force spectroscopy (AFMFS) method. Single-layered, double-layered, and multi-layered SEI structures with various Young's moduli have been visualized three dimensionally at nanoscale based on the hundreds of force curves in certain scanned area. The coverage of the SEI can be obtained quantitatively from the two-dimensional (2D) project plots. The related analysis indicates that more soft SEI layers are covered on the Si anode, and this could explain the benefits of the FEC additive.

Understanding the Li diffusion mechanism and positive effect of current collector volume expansion in anode free batteries

Yan Zhuang(庄严), Zheyi Zou(邹喆乂), Bo Lu(吕浡), Yajie Li(李亚捷), Da Wang(王达), Maxim Avdeev, Siqi Shi(施思齐)

Chin. Phys. B, 2020, 29 (6): 068202

Abstract: In anode free batteries (AFBs), the current collector acts as anode simultaneously and has large volume expansion which is generally considered as a negative effect decreasing the structural stability of a battery. Moreover, despite many studies on the fast lithium diffusion in the current collector materials of AFB such as copper and aluminum, the involved Li diffusion mechanism in these materials remains poorly understood. Through first-principles calculation and stress-assisted diffusion equations, here we study the Li diffusion mechanism in several current collectors and related alloys and clarify the effect of volume expansion on Li diffusion respectively. It is suggested that due to the lower Li migration barriers in aluminum and tin, they should be more suitable to be used as AFB anodes, compared to copper, silver, and lead. The Li diffusion facilitation in copper with a certain number of vacancies is proposed to explain why the use of copper with a thickness ≤ 100 nm as the protective coating on the anode improves the lifetime of the batteries. We show that the volume expansion has a positive effect on Li diffusion via mechanical-electrochemical coupling. Namely, the volume expansion caused by Li diffusion will further induce stress which in turn affects the diffusion. These findings not only provide in-depth insight into the operating principle of AFBs, but also open a new route toward design of improved anode through utilizing the positive effect of mechanical-electrochemical coupling.

Chinese Physics B (CPB)是由中国科学院物理研究所和中国物理学会主办，由合作出版商IOP Publishing海外宣传发行，目前国内载文量最大、影响力最大的物理类综合性英文学术期刊，报道和刊登国内外物理学科各领域（粒子物理与核物理类除外）创新性成果的“研究论文”、“研究快讯”及“前沿研究综述”。发文领域包括condensed matter and materials physics; atomic, molecular, and optical physics; statistical, nonlinear, and soft matter physics; plasma physics; interdisciplinary physics. 从投稿到录用平均审稿周期：2个月；文章录用后2天内网上预出版（with DOI）；每期评选封面文章、亮点文章并多渠道宣传推送；组织出版物理学热点研究领域和基础研究领域专题。