Zif-L Derived Carbon Flower with In-Situ Grown Cnts Accelerates the Reaction Kinetics of Li-Se Batteries

Abstract

Lithium-selenium (Li-Se) batteries have attracted increasing attention for their excellent carbonate electrolyte compatibility and considerable theoretical volumetric specific capacity. However, the development of Li-Se batteries is currently hindered by sluggish electrochemical reaction kinetics and the limitation in effectively utilizing active selenium. In this work, a ZIF-L derived carbon nanosheets flower is designed and synthesized as selenium host for Li-Se battery. On the one hand, the hierarchically porous system effectively confines Se species and alleviates volume expansion. On the other hand, the carbon nanosheets-assembled cross-linked conductive network provides shorter paths for charge/ion transfer. Particularly, with in-situ grown CNTs modification, superior cycling performance is ultimately achieved due to the enhanced electrochemical reaction kinetics. The Se/CNTs@HPC-5 cathode exhibits a reversible specific capacity of 606 mA h g-1 at 0.5 C after 350 cycles, with 0.013% capacity decay per cycle. After 400 cycles at a high current of 5 C, it can still maintain a capacity of 355 mA h g-1. This work would shed some light on the future development of carbon material for high-performance Li-Se batteries.

Keywords: ZIF-L, nanosheets-assembled carbon flower, CNTs, reaction kinetics, Li-Se batteries