Lithiophilic metal oxide-based double gradient anode host design for lithium-sulfur batteries

Abstract

The development of rechargeable lithium-sulfur (Li-S) batteries is hampered by Li dendrite growth and large volume changes in the anode. To tackle these issues, a novel double gradient anode host material consists of carbon nanofibers (CNFs) embedded ZnO and Co3O4 is developed. In this ZnOCo3O4/CNF composite, the decorated ZnO and Co3O4 forms lithiophilic and Li nucleation overpotential double gradient, which is beneficial for the uniform Li deposition and suppressing the irregular growth of Li dendrites. The 3D network structure of the CNFs substrate improves the electrical conductivity and buffering the stress of volume changes as well. Owing to these features, the ZnOCo3O4/CNF electrode exhibits stable voltage during the 400 h plating/stripping process at current density of 5 mA cm−2 and delivers an area capacity of 5 mAh cm−2. The Li@ZnOCo3O4/CNF||S/CNT battery maintains excellent stability with capacity decay rate of 0.036 % per cycle after 500 cycles at 1 C. The design of gradient anode hosts constructed from bimetallic oxides offers a promising alternative strategy for suppressing the irregular growth of Li dendrites, thereby increasing the cycle life of the batteries.