Spatially Confined in Situ Formed Sodiophilic-Conductive Network for High-Performance Sodium Metal Batteries
Xuan Lu, Ruochen Chen, Shenyu Shen, Yuyang Li, Hongyang Zhao, Hongkang Wang, Tiantian Wu, Yaqiong Su, Jianmin Luo, Xiaofei Hu, Shujiang Ding, Weiyang Li
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 2 S 3 nanoparticles encapsulated within the electrospun carbon nanofibers (Sb 2 S 3 @CNFs). The formed sodiophilic Na 3 Sb sites and the high Na + -conducting Na 2 S matrix, coupled with CNFs, establish a spatially confined “sodiophilic-conductive” network, which effectively reduces the Na nucleation barrier, improves the Na + diffusion kinetics, and suppresses the volume expansion, thereby inhibiting the Na dendrite growth. Consequently, the Na/Sb 2 S 3 @CNFs electrode exhibits a high Coulombic efficiency (99.94%), exceptional lifespan (up to 2800 h) at high current densities (up to 5 mA cm –2 ), and high areal capacities (up to 5 mAh cm –2 ) in symmetric cells. The coin-type full cells assembled with a Na 3 V 2 (PO 4 ) 3 /C cathode demonstrate significant enhancement in electrochemical performance. The flexible pouch cell achieves an excellent energy density of 301 Wh kg –1 .