• Layered iron vanadate ultrathin nanosheets (FeVO UNSs) with a thickness of ~ 2.2 nm were synthesized by a sonicate-assisted method.

• Pseudocapacitive Na⁺ intercalation of FeVO UNSs anode delivers high initial coulombic efficiency (93.86%), high reversible capacity (292 mAh g⁻¹), excellent rate capability, and remarkable cycling stability.

• A pseudocapacitor–battery hybrid SIC is assembled with the elimination of presodiation and delivers high energy and power densities.

中文翻译：

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具有Na+嵌入赝电容阳极的高能高功率赝电容器-电池混合钠离子电容器

• 
  通过超声辅助方法合成了厚度约为 2.2 nm 的层状钒酸铁超薄纳米片（FeVO UNS）。

• 
  FeVO UNSs负极的赝电容Na ⁺插层具有高初始库仑效率（93.86%）、高可逆容量（292 mAh g ^-1 ）、优异的倍率性能和卓越的循环稳定性。

• 
  赝电容器-电池混合 SIC 的组装消除了预沉淀，可提供高能量和功率密度。