Fig. 1

(a) Schematic diagram of various defects and ideal lattice in PBAs crystals[8]; (b) Two ways of Na+ migration in the crystal Na+ conduction through (001) crystal faces (left) and Na+ conduction through connected vacancies (right)[10]"

Fig. 2

Synthesis of highly crystalline Prussian white by chelating agent assisted coprecipitation[12]"

Fig. 3

(a) PB particle size when pH=0; (b) When pH=1, PB particle size; (c) When pH=2, PB particle size[15]"

Fig. 4

Corresponding SEM images of (a) original sample and (b) high-temperature sample; (c) Cycle curves of the original sample and the heat-treated sample at 1C current density; (d) Power properties of raw and heat-treated samples[22]"

Fig. 5

(a) Mechanism of acid etching during synchronous crystal growth and morphological modification; (b) PB-0.5H; (c) PB-1H; (d) PB-2H; (e) SEM images of PB-3H; (f) magnification properties of etching with different acid content[23]"

Fig. 6

(a)—(c) TEM images of PBMN samples at different magnifications; (d) Schematic diagram of the formation process of regular heterogeneous PBMN structure; (e) Specific capacity and coulomb efficiency of the PBMN electrode at different rates (current density :mA/g)[26]"

Fig. 7

(a) Schematic diagram of anode synthesis of tubular PB and derived tubular FeP; (b) SEM images of tubular PB; (c) TEM images of tubular PB; (d) Specific capacity at different current densities of 0.1—5.0 A/g; (e) Long-term cycle curve at 5.0 A/g[31]"

Fig. 8

(a)—(c) SEM and (d)—(f) TEM images of KNMF@3DFC at different magnifications; (g) Rate properties of KNMF and KNMF@3DFC composites; (h) Impedance spectra of KNMF and KNMF@3DFC composites[34]"

Fig. 9

FE-SEM images of (a) porous NFF and (d) porous NFF@PDA; (b)Transmission electron microscope images of porous NFF and (e) porous NFF@PDA; (c) HRTEM images of porous NFF and (f) NFF@PDA; (g) Schematic diagram of the synthesis process of porous NFF@PDA; (h) Cyclic properties of porous NFF and porous NFF@PDA at 0.2 A/g; (i) Magnification properties of porous NFF and porous NFF NFF@PDA[43]"

Table 1

Electrochemical performance of Prussian blue cathode materials for sodium-ion batteries"