Active Interphase Enables Stable Performance for an All‐Phosphate‐Based Composite Cathode in an All‐Solid‐State Battery

Small, vol. 18, pp. e2200266

Abstract

Abstract High interfacial resistance and unstable interphase between cathode active materials (CAMs) and solid‐state electrolytes (SSEs) in the composite cathode are two of the main challenges in current all‐solid‐state batteries (ASSBs). In this work, the all‐phosphate‐based LiFePO4 (LFP) and Li1.3Al0.3Ti1.7(PO4)3 (LATP) composite cathode is obtained by a co‐firing technique. Benefiting from the densified structure and the formed redox‐active Li3–xFe2–x–yTixAly(PO4)3 (LFTAP) interphase, the mixed ion‐ and electron‐conductive LFP/LATP composite cathode facilitates the stable operation of bulk‐type ASSBs in different voltage ranges with almost no capacity degradation upon cycling. Particularly, both the LFTAP interphase and LATP electrolyte can be activated. The cell cycled between 4.1 and 2.2 V achieves a high reversible capacity of 2.8 mAh cm–2 (36 µA cm–2, 60 °C). Furthermore, it is demonstrated that the asymmetric charge/discharge behaviors of the cells are attributed to the existence of the electrochemically active LFTAP interphase, which results in more sluggish Li+ kinetics and more expansive LFTAP plateaus during discharge compared with that of charge. This work demonstrates a simple but effective strategy to stabilize the CAM/SSE interface in high mass loading ASSBs.

Authors 11

1. Qi Xu Aachen Institute of Physical Chemistry

   Forschungszentrum Jülich · RWTH Aachen University

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

   Institute of Physical Chemistry RWTH Aachen University D‐52074 Aachen Germany

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

2. Zigeng Liu

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

3. Anna Windmüller

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

4. Shibabrata Basak

   Forschungszentrum Jülich · Ernst Ruska Centre

   Affiliation as printed

   Forschungszentrum Jülich, Ernst Ruska‐Centre for Microscopy and Spectroscopy with Electrons (ERC) D‐52425 Jülich Germany

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

5. Junbeom Park

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

6. Krzysztof Dzięcioł

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

7. Chih‐Long Tsai

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

8. Shicheng Yu corresponding

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

9. Hermann Tempel

   Forschungszentrum Jülich

   Affiliation as printed

   Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

10. Hans Kungl

    Forschungszentrum Jülich

    Affiliation as printed

    Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

11. Rüdiger‐A. Eichel Aachen Institute of Physical Chemistry

    Forschungszentrum Jülich · Helmholtz-Institute Münster · RWTH Aachen University

    Affiliation as printed

    Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany

    Forschungszentrum Jülich, Helmholtz Institute Münster: Ionics in Energy Storage (IEK‐12) D‐48149 Münster Germany

    Institute of Physical Chemistry RWTH Aachen University D‐52074 Aachen Germany

    Forschungszentrum Jülich, Fundamental Electrochemistry (IEK‐9) D‐52425 Jülich Germany