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Journal of Inorganic Materials

Journal of Inorganic Materials

   

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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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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