Ultrafine ZnSe Encapsulated in Nitrogen-Doped Porous Carbon Nanofibers for Superior Na-Ion Batteries with a Long Lifespan and Low-Temperature Performance
Xuewen Wang, Weiming Zhao, Wei Zhang, Ka Wai Wong, Jiawei Wu, Tong Chen, Shaoming Huang
Abstract
The inferior cycle lifespan and unsatisfactory energy density of traditional anode materials for sodium-ion batteries need to be improved toward actual application. Here, MOF-derived ultrafine ZnSe nanoparticles encapsulated within nitrogen-doped porous carbon nanofiber composites (ZnSe@NCNFs) are fabricated via in situ pyrolysis and selenylation from electrospun PAN@ZIF-8 nanofibers. As an anode, the ZnSe@NCNF electrode displays outstanding sodium-storage performance and superior cycling stability (197.3 mAh g–1 after 1700 cycles at 10 A g–1). Remarkably, the assembled SIBs work well in low temperatures within the range from −20 to −40 °C, showing the prospect for energy storage in an extreme environment. The impressive electrochemical properties are primarily due to the peculiar porous framework and ultrafine ZnSe nanoparticles, as well as a robust N-doped carbon matrix, which provide a penetrating network for fast ion/electron transfer and alleviate the pulverization of ZnSe during a sodiation/desodiation reaction. Moreover, the underlying reaction mechanism and outstanding reversibility of the ZnSe@NCNF electrodes are systematically revealed through ex situ X-ray diffraction/scanning electron microscopy (XRD/SEM) analysis and dynamic analysis.