POSITIVE ELECTRODE SHEET AND PREPARATION METHOD THEREOF
Provided is a positive electrode sheet and a preparation method thereof. The positive electrode sheet includes a current collector and a positive electrode material layer. The positive electrode material layer is coated on the current collector and includes a Prussian blue-type material containing crystal water, a conductive agent, a binder, and a gelatinous non-aqueous electrolyte. The positive electrode material layer has characteristics satisfying 0.1≤R2*(M1+M4)/((M2+M3)*R1)≤9, wherein the M1 represents a thermogravimetric loss rate of the Prussian blue-type material at 200° C.˜400° C.; the M2 represents a mass proportion of the conductive agent in the positive electrode material layer; the M3 represents a mass proportion of the binder in the positive electrode material layer; the M4 represents a mass proportion of the gelatinous non-aqueous electrolyte in the positive electrode material layer; the R1 represents a resistivity of the positive electrode sheet, and the R2 represents a resistivity of the current collector.
1 . A positive electrode sheet, comprising:
a current collector;
a positive electrode material layer, wherein the positive electrode material layer is coated on the current collector and comprises: a Prussian blue-type material containing crystal water, a conductive agent, a binder, and a gelatinous non-aqueous electrolyte, and the positive electrode material layer has characteristics satisfying 0.1≤R2*(M1+M4)/((M2+M3)*R1)≤9, wherein
the M1 represents a thermogravimetric loss rate of the Prussian blue-type material containing crystal water at 200° C.˜400° C.;
the M2 represents a mass proportion of the conductive agent in the positive electrode material layer;
the M3 represents a mass proportion of the binder in the positive electrode material layer;
the M4 represents a mass proportion of the gelatinous non-aqueous electrolyte in the positive electrode material layer; and
the R1 represents a resistivity of the positive electrode sheet in Ω·m, and the R2 represents a resistivity of the current collector in Ω·m.
2 . The positive electrode sheet according to claim 1 , wherein the Prussian blue-type material comprises one or more of Li + , Na + , and K + .
3 . The positive electrode sheet according to claim 1 , wherein the conductive agent is one or more of conductive carbon black, conductive graphite, carbon nanotubes, and carbon nanofibers.
4 . The positive electrode sheet according to claim 1 , wherein the binder is one or more of polyvinylidene fluoride, styrene butadiene rubber, nitrile rubber, polyimide, sodium carboxymethyl cellulose, sodium alginate, polyacrylic acid, and polytetrafluoroethylene.
5 . The positive electrode sheet according to claim 1 , wherein the gelatinous non-aqueous electrolyte has a dynamic viscosity of 10 4 Pa·s˜10 10 Pa·s.
6 . The positive electrode sheet according to claim 5 , wherein the gelatinous non-aqueous electrolyte comprises an electrolyte solute and an organic solvent mixed with the electrolyte solute, the electrolyte solute comprising a sodium salt and an organic solute mixed with the sodium salt, and a concentration of the sodium salt in the organic solute is 0.8 mol/L˜1.2 mol/L.
7 . The positive electrode sheet according to claim 6 , wherein the organic solute is one or more of polyethylene oxide, triethylene glycol divinyl ether, polyvinylidene fluoride-hexafluoropropylene, and polyacrylonitrile, and the organic solvent is one or more of acetonitrile, dimethylformamide, and anisole.
8 . The positive electrode sheet according to claim 6 , wherein a mass ratio of the electrolyte solute, the Prussian blue-type material containing crystal water, the conductive agent to the binder is (4˜6):(90˜95):1:1.
9 . The positive electrode sheet according to claim 1 , wherein M1=0.5%˜15%, M2=0.1%˜5%, M3=0.1%˜5%, M4=0.5%˜15%, R1=1˜100 Ω·m, and R2=0.03˜0.1 Ω·m.
10 . A preparation method of a positive electrode sheet, wherein the preparation method is used to prepare the positive electrode sheet according to claim 1 , comprising:
preparing a positive electrode slurry according to a preset proportion, wherein the positive electrode slurry comprises a gelatinous non-aqueous electrolyte, a Prussian blue-type material containing crystal water, a conductive agent, and a binder;
coating the positive electrode slurry on a current collector to form a positive electrode material layer; and
drying the current collector and the positive electrode material layer to form the positive electrode sheet, wherein
the positive electrode material layer has characteristics satisfying 0.1≤R2*(M1+M4)/((M2+M3)*R1)≤9; where
the M1 represents a thermogravimetric loss rate of the Prussian blue-type material containing crystal water at 200° C.˜400° C.;
the M2 represents a mass proportion of the conductive agent in the positive electrode material layer;
the M3 represents a mass proportion of the binder in the positive electrode material layer;
the M4 represents a mass proportion of the gelatinous non-aqueous electrolyte in the positive electrode material layer; and
the R1 represents a resistivity of the positive electrode sheet, and the R2 represents a resistivity of the current collector.
11 . The preparation method of a positive electrode sheet according to claim 10 , further comprising preparing the gelatinous non-aqueous electrolyte according to a preset proportion, comprising:
mixing a sodium salt with an organic solute to form an electrolyte solute, and then mixing the electrolyte solute with an organic solvent evenly to obtain a gelatinous electrolyte, wherein a concentration of the sodium salt in the organic solute is 0.8 mol/L˜1.2 mol/L.