Active Interphase Enables Stable Performance for an All‐Phosphate‐Based Composite Cathode in an All‐Solid‐State Battery. Issue 21 (27th April 2022)

• Record Type: Journal Article
• Authors: Xu, Qi; Liu, Zigeng; Windmüller, Anna; Basak, Shibabrata; Park, Junbeom; Dzieciol, Krzysztof; Tsai, Chih‐Long; Yu, Shicheng; Tempel, Hermann; Kungl, Hans; Eichel, Rüdiger‐A.
• Is Part Of: Small. Volume 18:Issue 21(2022)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2022-04-27
• Subjects: active interphases -- co‐fired LFP/LATP composite cathodes -- high areal capacity -- LATP redox; Nanotechnology -- Periodicals; Nanoparticles -- Periodicals; Microtechnology -- Periodicals; 620.5
• DOI: 10.1002/smll.202200266
• Languages: English
• ISSNs: 1613-6810

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 Li1.3 Al0.3 Ti1.7 (PO4 )3 (LATP) composite cathode is obtained by a co‐firing technique. Benefiting from the densified structure and the formed redox‐active Li3– x Fe2– x – y Ti x Al y (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. Abstract : A dense all‐phosphate‐based composite cathode with ion‐conductive and redox‐active interphase is fabricated via a co‐firing technique. The active interphase enhances the ionic conductivity of the composite cathode and meanwhile enables the stable performance of the bulk type all‐solid‐state battery, which has an industrially relevant reversible areal capacity.