Crumpling Carbon-Pillared Atomic-Thin Dichalcogenides and CNTs into Elastic Balls as Superior Anodes for Sodium/Potassium-Ion Batteries

With abundant electroactive sites and rapid ion diffusion paths, ultrathin dichalcogenides such as MoS2 demonstrate enormous potential as anodes for sodium/potassium-ion batteries (SIBs/PIBs). However, ultrahigh-aspect-ratio nanosheets are very easy to aggregate and re-stack, drastically weakening their intrinsic merits. Here a sustainable dichalcogenide anode is designed via crumpling carbon-pillared atomic-thin MoS2 nanosheets with CNTs into an elastic ball structure (C-p-MoS2/CNTs). In this architecture, the glucose-derived carbon pillars atomic-thin MoS2 nanosheets and broadens interlayer spacing, ensuring fast Na+/K+ diffusion; CNTs act as 3D scaffolds to impede re-stacking of MoS2 while providing high-speed pathways for electrons; the integration of flexible atomic-thin sheets and high-toughness CNTs further endows the balls with great elasticity to release the cycling stress. Consequently, the C-p-MoS2/CNTs material delivers high reversible capacities, outstanding cycling stability, and superior rate performance as anodes for both SIBs and PIBs. Pairing with Na3V2(PO4)(2)F-3 cathode, the sodium-ion coin-cell could operate at a rate up to 50 C at high mass loading of 9.4 mg cm(-2) and manifest ultrastable cycling stability at 40 C over 600 cycles. Impressively, the assembled pouch cell can be cycled stably with a high energy density of 188 Wh kg(-1). This study is anticipated to provide inspiration for designing innovative metal dichalcogenides as battery anodes.

Automated summary

By crumpling carbon-pillared atomic-thin MoS2 nanosheets with CNTs into an elastic ball structure, a sustainable dichalcogenide anode is designed, which exhibits high reversible capacities, outstanding cycling stability, and superior rate performance. The sodium-ion coin-cell can operate at a high rate and maintain stability. The assembled pouch cell has a high energy density.