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无机材料学报

• 研究论文 •    

NASICON型陶瓷固态电池的电化学电位界面调控

李勇锋1,2, 顾玉萍2,3,4, 师广照2,3,4, 胡九林2,3,4, 雷萌2,3,4, 彭晖1,5, 曾宇平2,3, 李驰麟2,3,4   

  1. 1.华东师范大学 物理与电子科学学院, 极化材料与器件教育部重点实验室, 上海 200241;
    2.中国科学院 上海硅酸盐研究所, 高性能陶瓷和超微结构国家重点实验室, 上海 201899;
    3.中国科学院大学 材料与光电研究中心, 北京 100049;
    4.中国科学院 上海硅酸盐研究所, 中国科学院能量转换材料重点实验室, 上海 201899;
    5.山西大学 极端光学协同创新中心, 太原 030006
  • 收稿日期:2024-12-16 修回日期:2025-03-07
  • 作者简介:李勇锋(1999–), 男, 硕士研究生. E-mail: 51254700112@stu.ecnu.edu.cn
  • 基金资助:
    国家自然科学基金(52372249)

Regulation of Electrochemical Potential Interfaces in NASICON-Type Ceramic Solid-State Batteries

LI Yongfeng1,2, GU Yuping2,3,4, SHI Guangzhao2,3,4, HU Jiulin2,3,4, LEI Meng2,3,4, PENG Hui1,5, ZENG Yuping2,3, LI Chilin2,3,4   

  1. 1. Key Laboratory of Polar Materials and Devices (MOE), Ministry of Education, School of Physics and Electronic Science, East China Normal University, Shanghai 200241, China;
    2. State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China;
    3. Center of Materials Science and Optoelectronics Engineering, University of Chinese Academy of Sciences, Beijing 100049, China;
    4. CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences, Shanghai 201899, China;
    5. Collaborative Innovation Center of Extreme Optics, Shanxi University, Taiyuan 030006, China
  • Received:2024-12-16 Revised:2025-03-07
  • About author:LI Yongfeng (1999–), male, Master candidate. E-mail: 51254700112@stu.ecnu.edu.cn
  • Supported by:
    National Natural Science Foundation of China (52372249)

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摘要： Li1.3Al0.3Ti1.7(PO4)3(LATP)是一种NASICON型固态电解质,其离子电导率高,化学稳定性优良,剪切模量(40~60 GPa)高。然而含四价钛离子的LATP在与锂金属负极接触时和循环过程中容易发生还原反应,进而导致电解质结构降解,并在电解质中引入电子电导。为了提高LATP的化学和电化学稳定性,本研究对LATP固态电解质表面进行了普鲁士蓝(PB)界面层的改性,优化了电解质与负极之间的接触。引入具有丰富开框架锂离子扩散通道的PB作为电解质-负极界面的混合导电改性层,具有如下优点：(1)锂化后PB层的本征电导率得到增强,可以加速界面层电子往负极的均化传输。(2)锂化过程中PB中间层的亲锂性增强,从而使电化学过程中LATP与锂金属之间的界面接触更加紧密。(3)锂化后PB仍然保持三维骨架结构,有利于实现界面处锂离子通量的均质化效应,从而提升锂沉积/剥离过程的稳定性。(4)具有金属有机框架(MOF)结构的PB可以保证循环过程中界面的机械稳定性,并减小锂负极的体积变化。(5)PB结构在锂化后不发生坍塌,不易出现相分离,不会形成额外的相边界或相缝隙,有利于集成锂离子流和电子流。(6)更为独特的是,PB的氧化还原电位高于界面两侧的锂金属和LATP,有利于在Li-LATP之间形成能垒,阻隔电子传输,防止LATP的还原降解。改进后的固态电池具有良好的循环稳定性和动力学性能。在0.025 mA·cm-2电流密度下,PB改性的Li/Li对称固态电池可稳定循环800 h。PB改性的Li/LiFePO4固态电池在为0.025 mA·cm-2电流密度下循环160圈后,容量还接近200 mAh·g-1。改性的Li/FeF3固态电池在0.025 mA·cm-2下可以保持高的库仑效率,表明PB改性对电化学循环过程中产生的体积变化具有较好的容忍性。

关键词: 固态电解质, 界面改性, NASICON型陶瓷, 普鲁士蓝, 固态锂电池

Abstract: Li1.3Al0.3Ti1.7(PO4)3(LATP), one of the NASICON-type solid-state electrolytes, possesses a high ionic conductivity, excellent chemical stability, and high shear modulus (40-60 GPa). However, the tetravalent titanium ion in LATP is particularly prone to undergo the reduction reaction with lithium metal during cycling, leading to the structure degradation and electron introduction in LATP electrolyte. In order to maintain the chemical and electrochemical stability of LATP, this work modified the surface of LATP solid electrolyte with a Prussian blue (PB) interfacial layer to optimize the contact between electrolyte and anode. Using PB with abundant open-frame lithium ion diffusion channels as the mixed conductive modification layer has the following advantages: (1) The intrinsic conductivity of PB layer is enhanced after lithiation, accelerating the homogenized transmission of electrons from the interfacial layer to the negative electrode. (2) The lithiation process is accompanied by the enhancement of the lithium affinity of PB intermediate layer, which makes the interface contact between LATP and lithium metal closer during the electrochemical process. (3) The lithiated PB still maintains a three-dimensional skeleton structure, which is conducive to the homogenization effect of lithium ion flux at interface, thereby promoting the stabilization of lithium deposition/stripping process. (4) The PB with metal-organic framework(MOF) structure is conducive to ensuring the mechanical stability of interface during cycling and reducing the volume change of lithium negative electrode. (5) The PB structure does not collapse after lithiation, and it is not easy to lead to phase separation and additional phase boundaries or phase gaps, which is conducive to the integration of lithium ion flow and electron flow. (6) More uniquely, the redox potential of PB is higher than those of lithium metal and LATP on both sides of the PB interface, and it is conducive to the formation of an electron transport barrier between Li and LATP, and prevents the reduction and degradation of LATP. The improved solid-state battery has good cycling stability and kinetic performance. At a current density of 0.025 mA·cm-2, the PB-modified Li/Li symmetric solid-state cell can achieve a stable cycle of 800 h. After 160 cycles at a current density of 0.025 mA·cm-2, the capacity of PB-modified Li/LiFePO4 solid-state battery is still close to 200 mAh·g-1. The modified Li/FeF3 solid-state battery can be operated at 0.025 mA·cm-2 with the preservation of a high Coulombic efficiency, indicating that the PB modification has good tolerance to the volume change generated during electrochemical cycling.

Key words: solid-state electrolyte, interface modification, NASICON type ceramics, Prussian blue, solid-state lithium batteries

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