Table 2.
Summary of soft materials for wearable energy conversion and storage devices.
| Class of Soft Material | Electrodes | Electrolyte | Endplate/Current Collector/Support | Shape/ Conformation |
Properties | Device | Ref. |
|---|---|---|---|---|---|---|---|
| Polymer | c | c | Au-deposited cyclo-olefin polymer | scotch-tape | flexible | PEMFC | [79] |
| Metal | Ag | c | Ag | nanowires | high electron conductive/flexible | PEMFC | [89,90] |
| CNTs | CNTs/carbon paper | c | plastic membrane | air-breathing cathode | lightweight, flexible, bendable, stretchable, twistable | PEMFC | [91] |
| Carbon-based | pyrolyzed - Zn/Co-ZIFs/polymer nanofibers | c | / | MOF fibers |
ORR OER electrocatalyst | PEMFC, Zn–air batteries |
[95] |
| polymer | c | c | Au-sputtered SOI wafers filled with Nafion | flat | thin, flexible | PEMFC | [97] |
| polymer | / | polyimide membrane | / | flat | lightweight, flexible ionic-electron conductive |
PEMFC | [98] |
| polymer | / | in-situ gelled chitosan | / | flat | green, soft, highly proton conductive, flexible | PEMFC, DMFC | [99,100] |
| CNTs | CNT/Si and CNT/LMO composite yarn |
c | c | fibers | flexible | LIBs | [120] |
| CNTs | MWCNTs/LiO composite yarns | c | absent | wire-shaped fiber |
lightweight, flexible, | LIBs | [122] |
| CNTs | CNTs sheets/PDMS | c | c | sandwich structure | lightweight, flexible, stretchable | LIBs | [123] |
| metal nanostructures | hierarchical nanostructured 3D ZnCo2O4 arrays on carbon cloth | c | c | hierarchical | flexible and thin | LIBs | [126] |
| polymer | poly(vinylidene fluoride-co-hexafluoropropylene)-based gel electrolytes | c | c | flat | tensile strength, elasticity | LIBs | [134,135,136,137,138] |
| graphene | N-doped 3D porous graphene/cotton cloth | c | c | flat | high specific surface area, mechanical resistance, electron conductive | LIBs | [127] |
| polymer | c | poly(vinylidene fluoride-co-hexafluoropropylene) gel | c | flat | flexible, bendable | LIBs | [138] |
| polymer | c | polyurethane/poly(vinylidene fluoride) membrane | c | flat | stretchable ionic conductive |
LIBs | [139] |
| CNTs Polymer Nanostructured metal |
MnO2/SWCNTs cathode Zn foil anode |
polyethylene oxide/TiO2 nanoparticles | carbon nanofiber mats current collector | flat | flexible | Zn–carbon | [145,146] |
| CNTs Nanostructured metal |
3D CNTs/Ni foam cathode | c | c | flat | flexible | Zn–air battery |
[150] |
| CNTs | Zn nanosheet/CNTs fibers anode ZnHCF/CNTs sheets cathode | c | c | coaxial-fiber | flexible, bendable, stable | Zn-ion battery |
[154] |
| polymer | / | porous gelatin-based | / | flat | flexible, waterproof | Zn-ion battery |
[156] |
| rGO/CNTs | rGO/CNTs/S | c | c | fiber | flexible | Li–S | [167] |
| graphene | graphene foam/S | c | c | cable-shaped | surface area, electron conductive, flexible | Li–S | [169] |
| graphene, CNTs | Ink filler | / | / | ink filler | flexible, electron conductive | EFCs | [213,214,215] |
| conductive polymer |
polystyrene sulfonate/polyethyleneimine/polypyrrole | c | c | ink filler | flexible, electron conductive | EFCs | [216,217,218] |
| graphene, CNTs | paper anode Carbon sheets/CNTs/mediator complex cathode |
sprayed selective separation layer | c | flexible, electron conductive | MFCs | [234,235] | |
| GO, rGO | GO and rGO |
/ | / | fibers | SCs | [252] | |
| graphene | graphene fiber wrapped with 3D graphene sheet | / | / | fiber wrapped 3D |
flexible, electron conductive, compressible | SCs | [254] |
| graphene | thin graphene |
c | Au current collector, PET substrate | thin | flexible, electron conductive, | SCs | [253] |
| CNTS | SWCNTs | PVP-H2SO4 gel | substrate | self-healing, flexible | SCs | [255] | |
| polymer | PANI/CNTs/ethylene-vinyl acetate copolymer | c | c | nanostructured | flexible, bendable | SCs | [259] |
| transition oxides | Hybrid WO3-Au MnO2 -based |
c | c | core-shell nanowires | flexible, bendable | SCs | [263] |
“c”: conventional; “/”: not available.