Double-functional 3D cross-linking carbon fiber with Sn particle coating layer for improving interfacial performance of Na-β″-Al2O3 batteries

Abstract

β″-Al2O3 solid-state electrolyte (BASE) possesses excellent ionic conductivity and stability with metallic sodium (Na) anode, which shows great application potential in solid-state sodium batteries. However, poor contact between Na anode and solid-state electrolyte causes high interfacial resistance and uneven anodic sodium deposition, which degrades the electrochemical performance of the battery and results in safety concerns. Herein, we demonstrate a double-functional layer composed of three-dimensional (3D) cross-linking carbon fiber with tin (Sn) particle (SC) coating on the BASE surface to enhance interfacial wettability and guide the uniform sodium-ion deposition during the cycling. Experimental results show that the assembled Na symmetric cell exhibits low interfacial area specific resistance (ASR) of 6.6 Ω cm2, and shows long-cycling performance for over 3000 h at 0.2 mA cm−2. The critical current density (CCD) reaches up to 1.3 mA cm−2 at 25 ℃. Moreover, with the SC modified layer, quasi-solid-state sodium cell with Na3V2(PO4)3 cathode presents excellent cycling and rate performance..