In situ formed self-embedded ion/electron conductive skeletons enabling highly stable sodium metal anodes

• Published in: Inorganic chemistry frontiers Vol. 11; no. 11; pp. 3211 - 3220
• Main Authors: Tao, Fang-Yu, Xie, Dan, Wang, Dan-Hong, Diao, Wan-Yue, Liu, Chang, Wu, Xing-Long, Li, Wen-Liang, Zhang, Jing-Ping
• Format: Journal Article
• Language: English
• Published: London Royal Society of Chemistry 28.05.2024
• Subjects: Anodes; Batteries; Deposition; Electrode polarization; Electrolytes; Nucleation; Sodium; Stability
• ISSN: 2052-1553; 2052-1545; 2052-1553
• DOI: 10.1039/D4QI00654B

Sodium (Na) metal has been considered as one of the most promising anodes for achieving next-generation battery systems with high energy density and low cost. Nevertheless, the uncontrolled dendrite growth, infinite volume expansion, and unstable solid/electrolyte interphase severely hinder the practical application of Na metal batteries. Herein, a self-embedded 3D ion/electron-conductive framework consisting of Na 15 Sn 4 (3D IECF) throughout the Na metal (referred to as NSN-3D IECF) is successfully prepared through the spontaneous alloy reaction between Na and Sn (4Sn + 15Na → Na 15 Sn 4 ). The self-embedded 3D IECF, featuring an interconnection network, not only facilitates rapid Na + transfer under high current density, but also offers abundant space for Na + deposition, which alleviates the volume expansion of the electrode during repeated cycling and maintains the interfacial stability of the anode/electrolyte. Meanwhile, the strong affinity between metallic Na and Na 15 Sn 4 lowers the nucleation energy barrier, achieving uniform and compact Na metal deposition with a dendrite-free morphology. Benefiting from these merits, the NSN-3D IECF-based symmetrical cell exhibits excellent stability at 1 mA cm −2 and 1 mA h cm −2 for more than 4000 h and a low polarization voltage (10 mV). More importantly, the full battery paired with the Na 3 V 2 (PO 4 ) 2 F 3 cathode maintains a reversible capacity of 106.2 mA h g −1 after 650 cycles at 5 C.