Conductive MWCNTs-decorated KVPO4F@C nanocomposite as a high-property cathode for potassium energy storage

Potassium vanadium fluorophosphate (KVPO₄F) has been regarded as one of the most promising cathode materials for potassium-ion batteries due to its advantages of high theoretical capacity, high operating voltage and high energy density. However, the low electrical conductivity of pristine KVPO₄F cathode remains a major issue that needs to be addressed. In this research, conductive MWCNTs-modified KVPO₄F@C (MWCNTs-KVPO₄F@C) nanocomposite has been firstly fabricated using a simple approach. SEM and TEM results indicate that the added one-dimensional MWCNTs are uniformly dispersed among the KVPO₄F@C nanoparticles. Benefiting from the excellent electrical conductivity of MWCNTs, the fabricated MWCNTs-KVPO₄F@C electrode exhibits good potassium storage performances including cyclic stability and high-rate capability. The initial discharge capacities of MWCNTs-KVPO₄F@C can reach 122.9 and 89.5 mAh g⁻¹ at 0.05 and 0.5 A g⁻¹, respectively. Even at a high rate of 1 A g⁻¹ for 600 cycles, its capacity retention ratio still reaches 92.5 %. These results prove that the fabricated MWCNTs-KVPO₄F@C material has feasibility in potassium energy storage high specialty cathode materials.