Single-crystal FeFe(CN)6 nanoparticles: a high capacity and high rate cathode for Na-ion batteries

Abstract

Prussian blue analogues are actively explored as low cost and high capacity cathodes for Na ion batteries; however, their applications are hindered by low capacity utilization and poor cyclability of these compounds. Here we show that this problem can be solved by controlling the purity and crystallinity of the Prussian blue lattices. As a model compound, single-crystal Fe III Fe III (CN) 6 nanoparticles are synthesized and found to have a sufficiently high capacity of 120 mA h g À1 , an exceptional rate capability at 20 C and superior cyclability with 87% capacity retention over 500 cycles, showing great promise for Na ion battery applications. More significantly, these results provide a new insight into the intercalation chemistry of Prussian blue analogues and open new perspectives to develop Na storage cathodes for widespread applications of electric energy storage.

Na2NixCo1−xFe(CN)6: A class of Prussian blue analogs with transition metal elements as cathode materials for sodium ion batteries

“…3(b). Owing to the structural imperfection and abnormal cationic arrangement of the PBC lattices, the Na + insertion/extraction process in the PBC may lead to a large volume variation to accommodate the structural change [24]. However, PBN exhibits a low mechanical strain, leading to more stable cycling performance.…”

Facile Method To Synthesize Na-Enriched Na1+xFeFe(CN)6 Frameworks as Cathode with Superior Electrochemical Performance for Sodium-Ion Batteries

“…FeFe(CN)6 had good cycling stability with a slight capacity decay from the initial 120 to 115 mAh g -1 after 150 cycles, 18 and Goodenough's group also suggested that KFeFe(CN)6 exhibits excellent capacity retention of more than 99% after 30 cycles. 15 A fatal flaw, however, is that…”

Recent Progress in Electrode Materials for Sodium‐Ion Batteries

“…[ 237 ] In addition, the highly crystalline NaFe 2 (CN) 6 /graphene composite delivered a discharge capacity of 150 mA h g −1 with an energy density of 280 Wh kg −1 . [ 238 ] The family of alkali-ion-defi cient cubic AM II Fe III (CN) 6 (A = Na or K) compounds requires a presodiation process to be combined with conventional Na-free anodes; otherwise, the electrode operation undergoes only one electron transfer with Fe 3+ /Fe 2+ redox couples, resulting in a low capacity below 70 mA h g −1 .…”