Spatially Confined in Situ Formed Sodiophilic-Conductive Network for High-Performance Sodium Metal Batteries.

Lu, Xuan; Chen, Ruochen; Shen, Shenyu; Li, Yuyang; Zhao, Hongyang; Wang, Hongkang; Wu, Tiantian; Su, Yaqiong et al. · Nano Lett · 2024

basic_science · Level V

Where this comes from

Abstract

The sodium (Na) metal anode encounters issues such as volume expansion and dendrite growth during cycling. Herein, a novel three-dimensional flexible composite Na metal anode was constructed through the conversion-alloying reaction between Na and ultrafine Sb<sub>2</sub>S<sub>3</sub> nanoparticles encapsulated within the electrospun carbon nanofibers (Sb<sub>2</sub>S<sub>3</sub>@CNFs). The formed sodiophilic Na<sub>3</sub>Sb sites and the high Na<sup>+</sup>-conducting Na<sub>2</sub>S matrix, coupled with CNFs, establish a spatially confined "sodiophilic-conductive" network, which effectively reduces the Na nucleation barrier, improves the Na<sup>+</sup> diffusion kinetics, and suppresses the volume expansion, thereby inhibiting the Na dendrite growth. Consequently, the Na/Sb<sub>2</sub>S<sub>3</sub>@CNFs electrode exhibits a high Coulombic efficiency (99.94%), exceptional lifespan (up to 2800 h) at high current densities (up to 5 mA cm<sup>-2</sup>), and high areal capacities (up to 5 mAh cm<sup>-2</sup>) in symmetric cells. The coin-type full cells assembled with a Na<sub>3</sub>V<sub>2</sub>(PO<sub>4</sub>)<sub>3</sub>/C cathode demonstrate significant enhancement in electrochemical performance. The flexible pouch cell achieves an excellent energy density of 301 Wh kg<sup>-1</sup>.