Rose-like VS2 Nanosheets Chemically Anchored on Carbon Nanotubes for Flexible Zinc-Ion Batteries with Enhanced Properties

Rechargeable aqueous zinc-ion batteries (ZIBs) are an attractive alternative for flexible energy storage devices due to their excellent safety and low cost. One of the main challenges that plagues their practical applications is the restricted variety of cathode materials with fast reaction kinetics and good mechanical properties. Herein, we prepared rose-like VS2 nanosheets which have decent specific capacities, metallic conductivity, and open enough channels and further incorporated them into a single-walled carbon nanotube (SWCNT) network, achieving a C-V chemical bonded freestanding VS2@SWCNT (C-VS2) composite. Such chemical bonding in the composites builds a bridge for rapid electron transfer and ion diffusion in the longitudinal direction from one layer to another layer. As a result, the reversible Zn/C-VS2 system in core cells exhibits a high specific capacity (205.3 mA h g(-1) at 0.1 A g(-1)), an excellent cyclic stability (115.4 mA h g(-1) was obtained after 1500 cycles at 5 A g(-1)), and a remarkable rate capability (135.4 mA h g(-1) at 10 A g(-1)). Furthermore, the freestanding C-VS2 films with good flexibility and conductivity can serve as a flexible cathode to assemble soft-packaged ZIBs. Meanwhile, the soft-packaged ZIB has good electrochemical stability even under different bending conditions (the discharge capacity dropped by only 2.1 mA h g(-1) after bending). This work offers insights into the rational design of zinc-ion hosts throughout chemical bond engineering.

Automated summary

In this study, rose-like VS2 nanosheets were prepared and incorporated into a SWCNT network to form a C-VS2 composite. The composites showed rapid electron transfer and ion diffusion due to the chemical bonding between layers. The reversible Zn/C-VS2 system exhibited high specific capacity, excellent cyclic stability, and remarkable rate capability. The flexible C-VS2 films also served as a cathode for soft-packaged ZIBs, which showed good electrochemical stability even under bending conditions.