Concurrent Defect Healing and Electronic Hybridization Enabling Ultrahigh-Rate and Long-Life Prussian Blue Cathodes

Prussian blue analogues (PBAs) are promising cathodes for sodium-ion batteries, yet intrinsic [Fe(CN)6] vacancies, interstitial water, and poor electronic conductivity compromise their rate capability and structural stability. Here, we develop a sequential dual-modification strategy that simultaneously suppresses lattice defects and constructs a three-dimensional (3D) conductive network. Sodium carboxymethyl cellulose (CMC) regulates crystallization to minimize [Fe(CN)6] vacancies and coordinated water, thereby stabilizing the open framework, while Ketjen black (KB) forms an interconnected conductive matrix that promotes charge-transfer kinetics through host–guest electronic hybridization. This multiscale regulation accelerates Na+ transport and reduces interfacial resistance, enabling the optimized PBA cathode to deliver 109.2 mAh g–1 at 5 A g–1 and retain 86.6% of its capacity after 10,000 cycles. This work establishes a generalizable strategy integrating defect suppression and electronic hybridization for designing durable, high-rate electrode materials for high-power energy storage.