Heteroatom molybdenum doping-driven morphology regulation for high-performance VS4@HNaV6O16·4H2O cathode in aqueous zinc-ion batteries

Aqueous zinc-ion batteries have attracted tremendous research interest for large-scale energy storage applications due to their resource abundance, high theoretical/volumetric capacity, and environmental friendliness. However, their development is hindered by sluggish Zn 2+ kinetics in cathode materials, caused by strong electrostatic interactions, and by unsatisfactory cycle life. In this work, we developed a Mo-doped VS 4 @HNaV 6 O 16 ·4H 2 O cathode that exhibits excellent electrochemical performance. The relative Mo content strongly influences the morphology of the cathode materials. With optimized doping at 3.0%, the structure evolves from spherical nanoparticles anchored on elongated layered structures to nanosized particles with a rose-like morphology. The optimized Mo-doped VS 4 @HNaV 6 O 16 ·4H 2 O cathode, coated on a stainless steel foil current collector, achieved a specific capacity of 427 mAh g −1 and an energy density of 281.8 Wh kg −1 at 0.3 A g −1 . At a high current density of 10 A g −1 , it delivered 171 mAh g −1 with ~66% capacity retention after 10,000 cycles. Furthermore, when tested with different current collectors, the best performance was obtained with carbon cloth, delivering a specific capacity of 451 mAh g −1 and an energy density of 297 Wh kg −1 at 0.3 A g −1 , along with 176 mAh g −1 and ~76% capacity retention after 10,000 cycles at 10 A g −1 . This study highlights the effectiveness of Mo doping and the critical role of current collector selection, providing valuable insights for the design of high-performance aqueous zinc-ion energy storage systems.