Fig. 1

Microstructure of dry electrodes[19]"

Table 1

Properties of binders commonly used in dry electrode technology"

Table 2

Dry electrodes versus wet electrodes"

Fig. 2

The evolution of dry electrode technology[40]"

Fig. 3

(a) The number of patents for dry powder spray deposition and polymer fibrillation in lithium-ion batteries[41]; (b) The number of published articles on the Web of Science with the keyword “lithium-ion batteries with dry electrodes or solvent-free electrodes” for the period 2006—2022[41]; (c) The distribution of patents for polymer fibrillation and dry powder spray deposition[24]; (d) Number of patents filed by different countries as a percentage of total patents[24]; (e) Number of patents filed by each country for polymer fibrillation and dry powder spray deposition[24]"

Fig. 4

(a) Schematic diagram of active graphene/activated carbon dry electrode preparation process[44]; (b) Diagram of the dispersion state of the electrode material[45]; (c) SEM images of the surface of the dry electrode[46]; (d) SEM images of the cross section of the dry electrode[46]; (e) SEM image of the surface of the wet electrode[46]; (f) SEM images of the cross section of the wet electrode[46]; (g)Capacity retention of supercapacitors during float charging[47]; (h) Resistance changes of supercapacitors during float charging[47]; (i) Rate performance of supercapacitors during float charging[47]"

Fig. 5

(a) Schematic diagram of polymer fibrillation used for the preparation of LFP electrode process[53]; (b) Schematic diagram of dry PVDF graphite electrode preparation process based on PTFE fibrillization[54]; (c) Schematic diagram of electrode preparation using dry powder spray deposition process[21]; (d) Schematic of the dry powder spray deposition process used to fabricate cathodes containing NMC, carbon black and PVDF[15]; (e) Schematic of NMC surfaces with different PVDF[62]"

Fig. 6

(a) Schematic of magnetron sputtering deposition setup[66]; (b) Schematic of all-solid-state cell using LiCoO2 thin film on Au and Pt single crystal (110) substrate[67]; (c) Specific energy of hypothetical LTO/LFP cell as a function of surface area and comparison between active material loading and commercial SoA[69]; (d) Schematic of dry process[29]; (e) Schematic of dry process for lithium-ion battery electrode preparation[70]"

Fig. 7

(a) Schematic of wet electrode process and direct pressing of dry electrodes for lithium-ion batteries[72]; (b) Schematic of uniformly applying a pressure of 2 MPa to a soft-packed cell using a pressure jig[73]; (c) Cross-sectional view of an all-solid-state battery[74]; (d) Schematic of a lithium-ion battery with 3D cross-finger microcellular architecture prepared by 3D printing[75]; (e) Schematic of a cross-finger electrode 3D-printed[76]"

Table 3

Summary of advantages, disadvantages and applications of six dry electrode technologies"