MOF-Derived Hierarchical CoP Nanoflakes Anchored on Vertically-Erected Graphene Scaffolds as Self-Supported and Flexible Hosts for Lithium–Sulfur Batteries
Lithium–sulfur (Li–S) batteries have garnered numerous attentions in the realm of electrochemical energy storage owing to their high energy and low cost. However, the serious polysulfide shuttle effect of the sulfur cathode poses a critical challenge for the development of Li–S batteries with elevated sulfur loadings. In addition, the poor robustness of traditional blade-casting cathodes greatly impedes the practical applications of flexible Li–S cells harnessing high areal capacity. To address these concerns, we report herein a freestanding hybrid sulfur host via in-situ crafting of flexible carbon cloth (CC), vertically grown graphene nanoflakes over CC (G/CC) and metal-organic-framework derived CoP anchored on vertical graphene (CoP@G/CC). Thus-derived sulfur cathodes (CoP@G/CC-S) with typical sulfur loadings of 2 mg cm–2 exhibit outstanding electrochemical performances, including excellent rate capability (930.1 mAh g–1 at 3.0 C) and impressive cyclic stability (0.03% capacity decay per cycle after 500 cycles at 2.0 C). A high areal capacity of 8.81 mAh cm–2 at 0.05 C can also be harvested even at an elevated sulfur loading of 10.83 mg cm–2. In further contexts, flexible pouch cells based on the self-supported CoP@G/CC-S showcase favorable rate and cycling performances with high mechanical robustness.
- This article is part of the themed collection: Journal of Materials Chemistry A HOT Papers