Calcium ion batteries, though more sustainable than lithium-ion batteries, still face significant challenges, including the lack of highly rechargeable electrodes. Prepared Prussian blue nanodisk electrodes can significantly extend the longevity of Ca-based cells. The method involves precipitating 20-nm-thick nanodisks of Prussian green from Fe(NO₃)₃ and K₃Fe(CN)₆, followed by sodiation with NaI. The Prussian-blue-based cathode with polyacrylic acid/polyaniline binder delivers an initial discharging capacity of 77.6 mAh g⁻¹ at 0.1 A g⁻¹ and retains 91.0% capacity after 700 cycles. Polyvinyl fluoride is detrimental to the Ca-based cell, as its coulombic efficiency decreases from 94.8% (120th cycle) to 86.4% (400th cycle). With the same cathode, the Ca-based cell is much less sensitive to high current densities than the Na-based cell. This can be because only half the amount of cations is required to move in Ca-based systems compared to Na-based systems; thus, the charge-transfer resistance is noticeably reduced in Ca-based systems.

中文翻译：

---

具有普鲁士蓝纳米盘的超稳定钙离子电池

钙离子电池虽然比锂离子电池更具可持续性，但仍面临重大挑战，包括缺乏高度可充电的电极。制备的普鲁士蓝纳米圆盘电极可以显着延长钙基细胞的寿命。_{该方法包括从 Fe(NO 3} ) ₃和 K ₃ Fe(CN) ₆中沉淀出 20 nm 厚的普鲁士绿纳米圆盘，然后用 NaI 钠化。具有聚丙烯酸/聚苯胺粘合剂的普鲁士蓝基正极在 0.1 A g ^{-1下提供 77.6 mAh g -1的初始放电容量}并在 700 次循环后保持 91.0% 的容量。聚氟乙烯对钙基电池有害，因为其库仑效率从 94.8%（第 120 次循环）降至 86.4%（第 400 次循环）。使用相同的阴极，钙基电池对高电流密度的敏感性远低于钠基电池。这可能是因为与基于钠的系统相比，基于钙的系统只需要一半数量的阳离子移动；因此，电荷转移电阻在钙基体系中显着降低。