Stable Interfaces in a Sodium Metal-Free, Solid-State Sodium-Ion Battery with Gradient Composite Electrolyte

• Published in: ACS applied materials & interfaces Vol. 13; no. 33; pp. 39355 - 39362
• Main Authors: Ran, Lingbing, Tao, Shiwei, Gentle, Ian, Luo, Bin, Li, Ming, Rana, MdMasud, Wang, Lianzhou, Knibbe, Ruth
• Format: Journal Article
• Language: English
• Published: American Chemical Society 25.08.2021
• Subjects: Energy, Environmental, and Catalysis Applications; polymer; composite electrolyte; sodium metal-free anode; NASICON; solid-state battery
• ISSN: 1944-8244; 1944-8252
• DOI: 10.1021/acsami.1c09792

Composite electrolytes (CE) combining a ceramic filler and a polymer matrix is an effective way to enhance battery safety. But the increased ceramic filler mass fraction decreases the flexibility, which increases the interfacial resistance. To alleviate interfacial resistance further, a gradient composite electrolyte (GCE) using a Sc, Ge-doped Na3Zr2Si2PO12 (NZSP) as the ceramic filler and poly­(ethylene oxide) (PEO) as the polymer matrix is proposed. The outer layer contains a low concentration of ceramic filler to improve interfacial contact, and the central layer contains a high concentration of ceramic filler to inhibit dendrite penetration. This GCE possesses an enhanced conductivity (4.0 × 10–5 S cm–1 at 30 °C) and a reduced interfacial resistance. Furthermore, the safety was boosted using Sn4P3@CNT/C as the high-capacity anode active material and Na3V2(PO4)3 (NVP) as the cathode active material. This ultrasafe sodium metal-free, solid-state sodium-ion battery (SSSIB) displays an impressive cycling performance.