Synergistically exfoliated Na/P co-doped vanadium oxide nanostructures with enhanced charge transport for high-capacity Li-ion battery anodes

초록

Rising interest in high-performance lithium-ion batteries (LiBs) has intensified the search for advanced anode materials with enhanced capacity, long-term stability, and excellent rate capabilities. Vanadium oxide (V2O5), owing to its high theoretical capacity and versatile redox chemistry, is a promising candidate but faces challenges such as poor cycling stability and low conductivity. In this work, we introduce a simple and scalable two-step method to synthesize a sodium- and phosphorus-doped vanadium nanocomposite (NaVP) designed to overcome these limitations. Electrochemical tests reveals that NaVP delivers an initial discharge capacity of 941 mAh g- 1, significantly higher than that of NaV (664 mAh g- 1), with an average cell discharge voltage of 3.0 V. Moreover, NaVP exhibits improved rate capability and lower charge-transfer resistance (Rct = 350 S2) compared to NaV (Rct = 400 S2). According to methodical comparisons, P alters the local vanadium-oxygen coordination and solid-electrolyte interphase (SEI) chemistry, allowing for faster Li+ transit and better cycling stability, whereas Na functions as an intercalant and stabilizer of the layered framework. These findings suggest that NaVP is a promising next-generation anode material and co-doping can be an economical way to enable highperformance vanadium-based anodes for Li-ion batteries.

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