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Orthogonal decoupling of an ionic-electronic transport microarchitectured vertical array cathode for flexible sodium-ion batteries
Sodium-ion batteries (SIBs) have emerged as a promising alternative to lithium-ion batteries due to the abundance and cost-effectiveness of sodium resources. However, their widespread application is hindered by challenges such as sluggish ion diffusion kinetics and structural instability of cathode materials during prolonged cycling. The design of advanced cathode architectures with enhanced ion transport and mechanical resilience is therefore crucial for achieving high-performance SIBs. Here, we present a vertically aligned Na3V2O2(PO4)2F3 (NVOPF) microarchitectured cathode with an orthogonally decoupled ionic-electronic transport pathway, which significantly enhances electrochemical performance. The in-situ engineered single-crystalline nanorod structure, anchored on a carbon nanotube substrate, not only enhances interfacial stability but also facilitates rapid Na+ diffusion (5.82 × 10-12 m2 s-1). This optimized microarchitecture exhibits a high discharge capacity of 131.16 mAh g-1 at 0.2 C and demonstrates excellent long-term cycling stability, retaining 95.99% of its capacity after 1,000 cycles at 3 C. Moreover, its outstanding rate capability (85.53 mAh g-1 at 5 C) underscores its potential for next-generation flexible energy storage systems. This work offers a new paradigm for designing high-loading cathodes, advancing the practical implementation of SIBs.