The battery's 3.7V is the nominal voltage, not the discharge 3.7V.
The discharge cut-off voltage is 3.0V, and the charge cut-off voltage is 4.2V.
The capacity of the battery is also based on the size of its cell. An analogy is easy to understand. A 5-liter bucket you want to fill with 5.5 liters of water is unrealistic. Fill it up to 5 liters and the benefits will come.
For example:
Specification of a steel shell core: 053652, we first find 05 thickness of the core capacity of 600mAh, and then with the thickness than the thickness of 36/30 = 1.2, with the coefficient of 600mAh first multiplied by 720mAh, and then with the length than the length of 52/48 = 1.08, with the coefficient of 720mAh first multiplied by = 780mAh, usually the capacity, but also the length of the steel shell core: 053652, we first find the thickness of 05, with the thickness of 600mAh. 780mAh, usually the capacity will not be so large, there will be some shrinkage, the empirical value of 90% -95%, so this specification of the capacity of the core is: 780mAh x 95% = 740mAh or so, this calculation is very accurate, generally will not appear large deviation, aluminum shell calculation with such the same, not introduced here