Lattice water removal from nickel–cobalt Prussian blue analogues by polyaniline coating for flexible sodium ion supercapacitor devices

Summary A new method to improve the performance of Prussian blue sodium ion supercapacitors by polyaniline coating is presented. The conducting mechanism of polyaniline film facilitates small water molecules transforming between benzene structure and quinone structure of polyaniline, which minimizes lattice water content of NiCo–Prussian blue analogues materials. The polyaniline-coated NiCo–Prussian blue analogues are loaded on carbon sponge material to assemble flexible supercapacitors. The specific capacity of 118.2 F g −1 , energy density of 32 Wh kg −1 , and power density of 6.23 kW kg −1 are obtained on NiCoPBA@PANI-1@CS//AC device, which are much greater than those of NiCoPBA@CS//AC without polyaniline coating.