Secondary battery and device including the same

A secondary battery, comprising:

• a negative electrode plate, including a negative current collector and a negative electrode film which is arranged on at least one surface of the negative current collector and includes a negative active material;
• a separation film, including a base material and a coating arranged on at least one surface of the base material;
• and
• an electrolyte, including an organic solvent,
• wherein the negative active material includes a silicon-based material and a carbon material;
• a thickness of the base material of the separation film is 7 μm˜12 μm;
• and
• the organic solvent includes ethylene carbonate (EC) and a weight ratio of the ethylene carbonate (EC) in the organic solvent is ≤20%,
• wherein the electrolyte further includes electrolyte salt, and the electrolyte salt includes lithium bisfluorosulfonimide (LiFSI) and lithium hexafluorophosphate (LiPF6);
• and
• molarity of the lithium bisfluorosulfonimide (LiFSI) in the electrolyte is 0.8 mol/L˜1.3 mol/L, and molarity of the lithium hexafluorophosphate (LiPF6) in the electrolyte is 0.15 mol/L˜0.4 mol/L.