High-performance sodium-ion batteries using Na₅PV₂Mo₁₀O₄₀ modified reduced graphene oxide (rGO) composite materials...

Sodium-ion batteries (SIBs) have gained increasing attention as a promising alternative to lithium-ion batteries, owing to the abundance and low cost of sodium. However, despite these advantages, the performance of SIBs is hindered by the larger ionic radius of sodium, which not only reduces ion migration rates but also significantly decreases the specific capacity. To address this challenge, the present study explores the synthesis of Na₅PV₂Mo₁₀O₄₀ (PV₂Mo₁₀)-modified reduced graphene oxide (rGO) composites by employing imidazole ionic liquid (IL) as electrostatic attraction agent, this approach not only prevents the aggregation of polyoxometalates (POMs) but also increases the interlayer distance of rGO, improving the battery's specific capacity and enhancing the diffusion rate of Na⁺ ions. Experimental results indicate that the PV₂Mo₁₀-rGO-IL hybrid material exhibits exceptional electrochemical properties, characterized by significantly improved conductivity and an impressive specific capacity of 290mAh g^-1 while achieving nearly 100 % Coulombic efficiency over 900 cycles. Furthermore, theoretical calculations reveal that the incorporation of POMs effectively reduces the electrode impedance of rGO and enhances the structural stability of POMs during cycling. This study opens up new avenues for the design of high-performance sodium ion batteries based on POMs.