Enhanced Performance of Ternary NASICON-Type Na3.5−Mn0.5V1.5−Zr (PO4)3/C Cathodes for Sodium-Ion Batteries

Sodium-ion batteries (SIBs) are widely studied for energy storage applications, but achieving cathode materials with balanced high energy density , stability, and fast charge/discharge performance remains a key challenge. In this study, we successfully synthesized a series of NASICON-type Na 3.5− x Mn 0.5 V 1.5− x Zr x (PO 4 ) 3 /C, incorporating Mn, V, and Zr to investigate their impact on electrochemical performance. By introducing Zr alongside Mn and V, we developed a novel strategy to activate V 4+ /V 5+ redox reactions , achieving high energy density . Moreover, this substitution promotes Na-ion migration by widening the migration pathways and generating additional Na vacancies, which greatly enhances electrode reaction kinetics and boosts overall performance. Na 3.4 Mn 0.5 V 1.4 Zr 0.1 (PO 4 ) 3 /C demonstrates superior stability, retaining 90% of its capacity after 800 cycles, and delivers high-rate performance (84 mAh∙g −1 at 20 C ), significantly outperforming pristine Na 3.5 Mn 0.5 V 1.5 (PO 4 ) 3 /C. These advancements highlight a potential approach for developing efficient and sustainable SIBs. The Zr-doped NASICON cathode exhibits enhanced cycling stability and high-rate performance, making it highly promising for advanced sodium-ion batte