Prussian blue analogue functionalized separators regulating Li+ flux for dendrite-suppressed lithium metal anodes

The development of high-energy-density lithium metal batteries (LMBs) is crucial for advanced energy storage but is hindered by uncontrolled lithium dendrite growth, largely stemming from non-uniform Li⁺ flux induced by commercial polypropylene (PP) separators. To address this, we fabricate a functionalized separator by modifying a PP separator with Prussian blue analog (PBA)-derived composite material (denoted as PG@PB). The resulting PP/PG@PB separator features a nanoscale porous structure that effectively regulates Li⁺ transport, significantly increasing Li⁺ transference number to 0.80 and promoting uniform Li deposition. Electrochemical characterization demonstrates that a Li||Li symmetrical cell employing PP/PG@PB achieves exceptional cycling stability, operating for 800 h at 1 mA cm⁻² with fixed specific capacity of 1 mAh cm⁻². Furthermore, the Li₄Ti₅O₁₂ (LTO)||Li full battery assembled with PP/PG@PB exhibits superior long-term cycling performance, retaining a high discharge capacity of ∼157 mAh g⁻¹ after 1000 cycles at 1C. These results underscore the crucial role of PP/PG@PB in homogenizing Li⁺ flux and suppressing Li dendrite formation, providing significant insights for designing high-performance LMBs.