Negative electrode current collector, negative electrode plate and electrochemical device
The present application discloses a negative electrode current collector, a negative electrode plate and an electrochemical device. The negative electrode current collector includes an organic support layer and a copper-based conductive layer disposed on at least one surface of the organic support layer; and a copper-based crystal grain size in the copper-based conductive layer is from 10 nm to 500 nm. The negative electrode current collector provided by the present application has good mechanics properties while having less weight and good electrical conductivity and current collection performance, which can improve preparation yields of the negative electrode current collector, the negative electrode plate and the electrochemical device and their safety and reliability during use, and enables the electrochemical device to have relatively high gravimetric energy density and good electrochemical performance.
1 . A negative electrode current collector, comprising an organic support layer and a copper-based conductive layer disposed on at least one surface of the organic support layer,
wherein the negative electrode current collector further comprises a protective layer that is disposed on a surface of the copper-based conductive layer facing away from the organic support layer; and
wherein the protective layer comprises one or more of nickel, chromium, nickel-based alloy, copper-based alloy, alumina, cobalt oxide, chromium oxide, nickel oxide, graphite, superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers,
wherein the organic support layer comprises one or more of polymer materials and the polymer materials are one or more of polyimide, and polyethylene terephthalate,
a thickness D 1 of the copper-based conductive layer and a copper-based crystal grain size d in the copper-based conductive layer satisfies 6.67≤D 1 /d≤10,
the copper-based conductive layer has a thickness D 1 of 600 nm≤D 1 ≤1.2 μm; and
the copper-based crystal grain size d in the copper-based conductive layer is from 100 nm to 150 nm.
2 . The negative electrode current collector according to claim 1 , wherein the organic support layer has a Young's modulus E of E≥2 GPa.
3 . The negative electrode current collector according to claim 1 , wherein the negative electrode current collector has an elongation at break of 3% or more.
4 . The negative electrode current collector according to claim 1 , wherein the organic support layer has a thickness D 2 of 1 μm≤D 2 ≤30 μm.
5 . The negative electrode current collector according to claim 1 , wherein the copper-based conductive layer comprises one or more of copper and copper alloy; and
the copper alloy comprises copper element and additional elements, the additional elements are selected from titanium, vanadium, nickel, chromium, iron, cobalt, manganese, zinc, zirconium, molybdenum, niobium, tungsten, silver, palladium and cadmium, a mass percentage of the copper element in the copper alloy is 80 wt % or more.
6 . The negative electrode current collector according to claim 1 , further comprising a second protective layer that is disposed on a surface of the copper-based conductive layer facing toward the organic support layer.
7 . A negative electrode plate, comprising a negative electrode current collector and a negative electrode active material layer disposed on the negative electrode current collector, wherein the negative electrode current collector is the negative electrode current collector according to claim 1 .
8 . An electrochemical device, comprising a positive electrode plate, a negative electrode plate and an electrolyte, wherein the negative electrode plate is the negative electrode plate according to claim 7 .
9 . The negative electrode current collector according to claim 2 , wherein the organic support layer has the Young's modulus E of 2 GPa≤E≤20 GPa.
10 . The negative electrode current collector according to claim 4 , wherein the organic support layer has the thickness D 2 of 1 μm≤D 2 ≤15 μm.
11 . The negative electrode current collector according to claim 4 , wherein the organic support layer has the thickness D 2 of 1 μm≤D 2 ≤10 μm.
12 . The negative electrode current collector according to claim 4 , wherein the organic support layer has the thickness D 2 of 2 μm≤D 2 ≤6 μm.
13 . The negative electrode current collector according to claim 4 , wherein the organic support layer has the thickness D 2 of 1 μm≤D 2 ≤8 μm.
14 . The negative electrode current collector according to claim 4 , wherein the organic support layer has the thickness D 2 of 2 μm≤D 2 ≤8 μm.
15 . The negative electrode current collector according to claim 5 , wherein the protective layer has a thickness D 3 of 1 nm≤D 3 ≤200 nm, and the thickness D 3 of the protective layer and the thickness Di of the copper-based conductive layer satisfy: D 3 ≤0.1 D 1 .
16 . The negative electrode current collector according to claim 6 , wherein the copper-based conductive layer is a vapor deposited layer or an electroplated layer.