Solid lithium cell, battery comprising said cells and manufacturing process for manufacturing said battery
A solid lithium cell is formed by stacking an etched copper substrate, a layer of graphite, an electrolyte, and a layer of nickel, manganese, and cobalt oxides. The electrolyte is in contact with the graphite layer and the layer of nickel, manganese, and cobalt oxides. The copper substrate forms the anode of the cell. The layer of nickel, manganese and cobalt oxides forms the cathode of the cell. The electrolyte is a solid lithium-based electrolyte. The graphite layer has a first solid electrolyte interface produced during a pre-lithiation with a liquid lithium-based electrolyte and a second solid electrolyte interface produced during a pre-lithiation with the solid lithium-based electrolyte.
1 . A solid lithium cell formed by stacking of an etched copper substrate, of a graphite layer, of an electrolyte, and of a layer of nickel, manganese and cobalt oxides, the electrolyte being in contact with the graphite layer and the layer of nickel, manganese and cobalt oxides, the copper substrate forming an anode of the cell, and the layer of nickel, manganese and cobalt oxides forming a cathode of the cell,
in which the electrolyte is a solid lithium-based electrolyte and the graphite layer exhibits a first solid electrolyte interface produced during a prelithiation with a liquid lithium-based electrolyte and a second solid electrolyte interface produced during a prelithiation with the solid lithium-based electrolyte.
2 . The solid lithium cell as claimed in claim 1 , in which the solid lithium-based electrolyte is a porous membrane electrolyte made of poly(vinylidene fluoride)-poly(hexafluoropropylene) improved with lithium bis(trifluoromethylsulfonyl) imide.
3 . The solid lithium cell as claimed in claim 1 , in which the copper substrate and the graphite layer are rendered integral mechanically.
4 . The solid lithium cell as claimed in claim 1 , in which the layer of nickel, manganese and cobalt oxides is of formula LiNi x Mn y Co z O 2 , where x, y, and z represent atomic percentage values and x is of between 0.3 and 0.8, y is of between 0.1 and 0.3, and z is of between 0.1 and 0.3.
5 . A solid lithium battery comprising at least two of the solid lithium cells as claimed in claim 1 , the cells being fitted in parallel.
6 . A manufacturing process for manufacturing the solid lithium battery as claimed in claim 5 , comprising the following stages:
carrying out a wet etching of a copper substrate in order to obtain a relief pattern,
placing a graphite layer on the etched copper substrate,
assembling a first cell comprising the graphite layer on the etched copper substrate, a layer of nickel, manganese and cobalt oxides and a liquid lithium-based electrolyte in contact both with the graphite layer and with the layer of nickel, manganese and cobalt oxides,
carrying out a prelithiation of the graphite layer of the first cell,
withdrawing, from the first cell, the prelithiated graphite layer placed on the etched copper substrate,
assembling a second cell comprising the prelithiated graphite layer on the etched copper substrate, a layer of nickel, manganese and cobalt oxides and a solid lithium-based electrolyte in contact with the prelithiated graphite layer and with the layer of nickel, manganese and cobalt oxides, and
assembling a solid lithium battery comprising at least two second cells in parallel.
7 . The manufacturing process for manufacturing the solid lithium battery as claimed in claim 6 , in which the prelithiation of the first cell is carried out with a discharge cycle, in a constant current and constant voltage mode at 0.05 C at ambient temperature and a voltage window of OCV-10 mV.
8 . The manufacturing process for manufacturing the solid lithium battery as claimed in claim 6 , in which the etching of the copper substrate comprises the following stages:
applying a solution of FeCl 3 , HCl and H 2 O for 30 seconds,
washing the copper substrate with an ammonium bicarbonate NH 4 HCO 3 solution and then with water, and
drying the copper substrate over a hot plate at 80° C.
9 . The manufacturing process for manufacturing the solid lithium battery as claimed in claim 6 , in which the solid lithium-based electrolyte is a dry polymer electrolyte.
10 . The manufacturing process for manufacturing the solid lithium battery as claimed in claim 9 , in which the solid lithium-based electrolyte is a porous membrane electrolyte made of poly(vinylidene fluoride)-poly(hexafluoropropylene) improved with lithium bis(trifluoromethylsulfonyl) imide.