Multi-wall carbon nanotube-induced nanobelt potassium vanadate composite as cathode for sodium-ion batteries

Sodium-ion battery is an ideal alternative to lithium-ion battery because of its resource-rich and cost-effective properties. Herein, potassium vanadate nanobelts composite (KV3O8-x@CNTsmiddot2.5H(2)O) induced by the multi-wall carbon nanotube (MWCNT) is synthesized via a hydrothermal treatment process as a cathode material for sodium-ion battery. The carbon nanotubes serve as the nucleation centers and induce the growth of potassium vanadate, which effectively decreases the agglomeration of potassium vanadate nanobelts. Besides, the characteristic 3D interconnected network structure provides a continuous conductive path with more adsorption sites for sodium ions. Therefore, KV3O8-x@CNTsmiddot2.5H(2)O exhibits high specific surface area and fast kinetics accordingly showing excellent electrochemical performance. The capacity can reach 138.9 mAh g(-1) at 20 mA g(-1) and keep a high retention rate of 85% at 2 A g(-1). Beneficial from the layered morphology, the composite exhibits a highly stable and reversible change during the repeated charge/discharge processes, and thence a high capacity retention rate of 81% after 240 cycles at 100 mA g(-1) can be achieved. This work presents a facile approach for further exploration of vanadate-based cathode materials in the field of sodium-ion batteries.

Automated summary

A potassium vanadate nanobelts composite as a cathode material for sodium-ion battery was successfully synthesized in this study, showing excellent electrochemical performance and high stability, providing a facile approach for further exploration of vanadate-based cathode materials.