Secondary battery, preparation method therefor, and electrical device

A secondary battery, comprising a negative electrode, wherein:

• the negative electrode comprises a current collector and an active material layer arranged on a surface of the current collector, the active material layer comprises a silicon-based material and a carbon-containing material, and the carbon-containing material comprises a first carbon material;
• the current collector comprises a main body portion and a tab located on one side of the main body portion, the main body portion comprises a first region and a second region, and the second region is located between the first region and the tab;
• the active material layer comprises a first active material layer and a second active material layer, the first active material layer is located in the first region, and the second active material layer is located in the second region;
• the percentage by weight of the silicon-based material in the second active material layer is greater than the percentage by weight of the silicon-based material in the first active material layer;
• and
• the percentage by weight of the first carbon material in the second active material layer is greater than the percentage by weight of the first carbon material in the first active material layer.