Fig. 1

Three major routes for presodiation"

Fig. 2

The working mechanism of presodium technologies[5]"

Fig. 3

(a) Schematic diagram of ball grinding process between sodium metal and base metal; In (b) and (d), X-ray diffraction patterns of Na3P and Na3Sb single-phase powders are shown, respectively; (c) and (e) show the corresponding electrochemical voltage curves of Na3P and Na3Sb single-phase powders in sodium half-cells, respectively[6]"

Fig. 4

Schematic mechanism of chemical sodium[7]"

Fig. 5

Battery cycle diagram of (a) conventional batteries and (b) batteries with cathode additives[13]"

Table 1

Typical additives and the performance of the batteries"

Fig. 6

Schematic diagram of the structural transition of the cathode after electrochemical presodium [29]"

Fig. 7

(a) The conductivity of a sodium-ion batteries with a black column can be seen, (b) Different electrolyte formulations of the same solvent with sodium salt[32]"

Fig. 8

(a) Mechanism diagram of FEC additives in rechargeable sodium-ion batteries with hard carbon and NaNi1/2Mn1/2O2 as electrodes; (b) The initial reduction and oxidation curves of the HC electrode in the PC electrolyte[33]"

Fig. 9

Schematic diagram of the rolling pressure of the direct pre-sodium metal method[27]"

Fig. 10

Ultrasonically dispersed sodium metal powder was prepared with electrode sheets[41]"

Fig. 11

(a) Schematic diagram of presodium of three-electrode batteries[44]; (b) Schematic diagram of short-circuit presodium[45]"

Table 2

Electrochemical properties of different anode materials"

Fig. 12

(a) A "card" model: blue and red represent different phases, respectively, with sodium ions inserted into the nanodomain and subsequently filled pores; (b) Model structure: mechanical model of sodium ion storage at defective sites and adsorption of sodium ions in the tiny pores of graphene sheets in the low pressure range; (c) Parameters related to the capacity curve of the typical potential of the hard carbon anode in sodium batteries; (d) Schematic diagram of the storage of sodium ions in layered hard carbon[60]"

Fig. 13

Capacity-voltage map of a sodium battery[61]"

Table 3

Comparison of the electrochemical performance of anode presodium agent"

Fig. 14

(a) The charge/discharge curves of NaFe0.5Ti0.5O2, (b) CV curves, (c) rate capabilities, (d) 1C cycling performance[25]"