More importantly, they can be stored at low state of charge, which is unlike detrimental to the life of Li-ion batteries. 2 However, Na-ion battery performance is often limited by challenges associated with sluggish ion diffusion and lower energy density compared to lithium-based systems. To overcome these limitations, many approaches are being adapted. Among these, one approach involves the use of two-dimensional (2D) materials and their innovative components particularly phosphorene, due to its high surface area, excellent electronic conductivity, tunable Van der Waals gap and unique layer-dependent properties. Phosphorene is a highly promising anode material for SIBs due to its ability to accommodate larger Na ions, unlike traditional carbon-based anodes, resulting in a high theoretical specific capacity of ~2600 mAh g⁻¹. DFT studies indicate that Na intercalation in phosphorene enables fast (0.04 eV energy barrier) and anisotropic diffusion while also triggering a semiconductor-to-metal transition at high Na concentrations, benefiting from its larger interlayer channel size (3.08 Å vs. 1.86 Å for graphite). However, the utilization of phosphorene to PQDs for Na-ion batteries requires a careful control over its physical dimensions to enhance its electrochemical performance for lithium-ion and SIBs. SIB cathodes mainly consist of layered transition metal oxides (e.g., NaxCoO2), polyanionic compounds (e.g., Na3V2(PO4)3), and Prussian blue analogs, each exhibiting unique benefits in terms of capacity, structural stability, and electrochemical performance. While layered oxides offer high capacity, polyanionic materials demonstrate enhanced stability due to strong covalent bonding within their framework. Among them Prussian white (PW) (NaxMa[Mb(CN)6]) stands out for its affordability, non-toxicity, and high energy density, making it a strong candidate for cathodes. Additionally, it features extensive three-dimensional ion diffusion channels, large sodium storage sites, and minimal lattice strain, allowing for quick Na + (de)intercalation while preserving structural integrity. Furthermore, PW can be synthesized through a simple coprecipitation method, bypassing the need for high-temperature sintering and significantly lowering production costs. Consequently, PW material shows great potential for development and practical application in cost-effective sodium-ion batteries (SIBs). However, exposure of PW to moisture leads to surface contamination and structural transformation from a rhombohedral to a monoclinic phase due to water absorption, while vacuum drying at 150 °C restores the rhombohedral structure by removing interstitial water but not surface impurities. Hence, combining PW with the size tailored PQDs, not only improves the specific capacity and rate capability of Na-ion batteries but also ensures the structural stability of the PQDs@PW over extended cycles.