Method for producing a supercapacitor
Components for energy storage, in particular to a process for producing a supercapacitor includes a flexible substrate, the process comprising at least the steps of unwinding the flexible substrate from a first roll, spraying a plurality of suspensions comprising micro/nanoparticles suspended in a solvent, the suspension(s) being sprayed by a plurality of nozzles, transporting at least a portion of the flexible substrate at least through a region for deposition of micro/nanoparticles, along a direction of transport of the flexible substrate, the interaction of the deposition region and of the flexible substrate forming an impact region, heating the flexible substrate, during each spraying operation, so as to encourage the complete evaporation of the solvent(s) from the suspensions sprayed onto the flexible substrate.
1. A process for producing a supercapacitor, comprising a flexible substrate, said process comprising at least the steps of:
unrolling said flexible substrate from a first roll;
spraying a plurality of suspensions comprising micro/nanoparticles suspended in a solvent, said suspensions being sprayed by a plurality of nozzles forming jets of droplets of said suspension defining a spatial region, referred to as deposition region;
transporting at least a portion of said flexible substrate through a region for deposition of micro/nanoparticles, along a direction of transport of said flexible substrate, the interaction of said deposition region and of said flexible substrate forming an impact region;
heating said flexible substrate, during each spraying operation, so as to encourage the complete evaporation of said solvent from said suspensions sprayed onto said flexible substrate;
said process being wherein the composition of said micro/nanoparticles of one said sprayed suspension is different from the composition of said micro/nanoparticles of at least one other said sprayed suspension,
wherein the assembly of said nozzles are arranged according to a matrix comprising rows and columns, said impact region of one said row being substantially transverse to the direction of transport of said flexible substrate,
and in that an assembly of at least two nozzles simultaneously sprays at least two suspensions substantially over the same impact region.
2. The process as claimed in claim 1 , comprising an additional step of winding said flexible substrate around a second roll.
3. The process as claimed in claim 1 , comprising at least one step of exchanging the position of each of said nozzles from a first group of said nozzles with the position of each of said nozzles from a second group of said nozzles.
4. The process as claimed in claim 1 , wherein said flexible substrate is locally planar in said impact region along a main plane, and wherein at least three of said nozzles are arranged in a plane that is parallel to, and different from, said main plane.
5. The process as claimed in claim 1 , wherein at least one said row sprays said suspensions with the same composition of said micro/nanoparticles and with a composition that is different from at least one other said row.
6. The process as claimed in claim 1 , wherein the composition of said micro/nanoparticles of said suspensions is periodical as a function of said rows.
7. The process as claimed in claim 1 , wherein said flexible substrate is planar along a main plane and said nozzles are arranged around at least one carousel, one axis of revolution being common to each of said carousels, said axis of revolution being substantially parallel to said main plane and substantially normal to said direction of transport of said flexible substrate, said process comprising at least one step of pivoting at least one said carousel about said axis of revolution.
8. The process as claimed in claim 1 , wherein two said nozzles of said assembly spray said suspensions of micro/nanoparticles with the same composition of micro/nanoparticles and of solvent at a different angle, substantially covering the same said impact region substantially homogeneously.
9. The process as claimed in claim 1 , comprising an additional step wherein said flexible substrate is heated during each spraying operation, so as to encourage the complete evaporation of said solvent(s) from said suspensions sprayed onto said flexible substrate, to a temperature less than or equal to one and a half times the boiling point of each said solvent and less than or equal to 200 degrees Celsius.
10. The process as claimed in claim 1 , wherein said micro/nanoparticles comprise graphene sheets.
11. The process as claimed in claim 1 , wherein at least a portion of the micro/nanoparticles is oxidized before they are suspended in a said solvent.
12. The process as claimed in claim 1 , wherein, before a spraying operation, said micro/nanoparticles are suspended in a said solvent composed of more than 95% water (H.sub.2O) by weight, and preferentially more than 99% water by weight.
13. The deposition process as claimed in claim 1 , said micro/nanoparticles of which are selected from carbon nanotubes, carbon nanofibers, carbon nanorods, carbon nanohorns, carbon onions and a mixture of these micro/nanoparticles, wherein said micro/nanoparticles are oxidized before they are sprayed, and wherein said deposit is annealed after said spraying operation at a sufficient temperature to deoxidize said micro/nanoparticles.
14. The process as claimed in claim 1 , wherein the thickness of said micro/nanoparticles deposited is measured during or after the deposition of said micro/nanoparticles.
15. An electrode comprising a said flexible substrate, said flexible substrate being covered with a deposit of micro/nanoparticles, said deposition of said micro/nanoparticles being able to be obtained by a process as claimed in claim 1 .
16. A supercapacitor comprising at least one said electrode as claimed in claim 1 .