Negative electrode plate, electrode assembly, lithium-ion battery and process for preparation thereof and apparatus containing lithium-ion battery

A lithium-ion battery, comprising an electrode assembly and an electrolyte, wherein the electrode assembly is an electrode assembly including a positive electrode plate, a negative electrode plate, and a separator, wherein the negative electrode plate is a negative electrode plate (10), comprising

• a negative electrode current collector (11);
• a negative electrode active material layer (12) disposed on the negative electrode current collector (11);
• a binder-free inorganic dielectric layer (13) disposed on one side of the negative electrode active material layer (12) away from the negative electrode current collector (11), the inorganic dielectric layer (13) comprising an inorganic dielectric material, and the inorganic dielectric layer (13) including at least a main body portion (131) disposed on the surface of the negative electrode active material layer (12), the main body portion (131) having a thickness of from 30 nm to 200 nm;
• and
• a lithium metal layer (14) disposed on the surface of the inorganic dielectric layer (13) away from the negative electrode active material layer (12),
• the inorganic dielectric layer (13) further comprises an extension portion (134) connected with the surface of the main body portion (131) facing toward the negative active material layer (132), the extension portion (134) extending along a wall surface of pores in the negative electrode active material layer (12) away from the main body portion (131) and covering the wall surface of pores in a form of a thin film,
• the dimension of the extension portion (134) in a thickness direction of the negative electrode active material layer (12) to the thickness of the main body portion (131) has a ratio of 1/1000 to 1/80;
• the inorganic dielectric material comprises oxides of Al;
• the negative electrode current collector is a copper foil;
• and
• the negative electrode active material layer (12) comprises a negative electrode active material, that is artificial graphite,
• wherein in the negative electrode plate per unit area of 2 cm×2 cm, a weight ratio of the lithium metal layer to the negative electrode active material layer is 0.5%˜5%;
• wherein a ratio of a capacity C1 of negative electrode per unit area to a capacity C2 of positive electrode per unit area is 1.2˜2.1;
• and
• wherein the capacity C1 of negative electrode per unit area, the capacity C2 of positive electrode per unit area and a capacity C3 of lithium metal layer per unit area satisfy C1/(C2+C3×K)≥1.05, where K is a utilization rate of metal lithium in the lithium metal layer.