Core–shell MWCNTs@ZnS composite prepared by atomic layer deposition for high-performance lithium-ion batteries anode

Abstract

In this work, zinc sulfide (ZnS) on hydroxylated multi-walled carbon nanotubes (MWCNTs) composite was prepared for lithium-ion batteries (LIBs) anode. It is demonstrated that atomic layer deposition (ALD) enables a conformal, uniform, and ultrathin ZnS (~ 7 nm) layer onto the surface of hydroxylated MWCNTs. The resulting MWCNTs@ZnS core–shell composite displays excellent electrochemical performances as LIBs anode, accounting for high capacity, stable cyclability, high rate capability, and exceptional coulombic efficiency. The MWCNTs@ZnS composite can exhibit a stable discharge capacity, sustaining 520 mAh g−1 versus 108 mAh g−1 for commercial ZnS powders after 200 cycles at 100 mA g−1. The improved electrochemical performances are attributed to the synergistic effect from MWCNTs and ALD ZnS film. MWCNTs have good conductivity and huge surface area while the ALD ZnS film has high Li storage capability. This study verifies that ALD is highly flexible in developing excellent electrodes of LIBs.