It is found that when x > 0.5, the structure of Li1-xCoO2 is extremely unstable, and the crystal form collapses and the external performance is the overwhelming end of the cell. Therefore, the x value in Li1-xCoO2 should be controlled by limiting the charging voltage during the use of the cell, and the general charging voltage is not greater than 4.2V, then x is less than 0.5, and the crystal form of Li1-xCoO2 is still stable.

The negative electrode C6 itself has its own characteristics, when the first formation, the Li in the positive electrode LiCoO2 is charged into the negative electrode C6, and when the discharge is discharged, Li returns to the positive electrode LiCoO2, but after the formation, a part of the Li must be left in the center of the negative electrode C6 to ensure the normal embedding of the next charge and discharge of Li, otherwise the overpowering of the battery cell is very short, in order to ensure that a part of Li remains in the negative electrode C6, Generally, it is achieved by limiting the discharge lower limit voltage: the upper limit voltage of safe charging ≤ 4.2V, and the lower discharge limit voltage ≥ 2.5V.

The principle of the memory effect is crystallization, which is almost impossible to produce in lithium batteries. However, the capacity of lithium-ion batteries still decreases after multiple charges and discharges, and the reasons for this are complex and varied. Mainly due to the changes in the cathode and anode materials themselves, from the molecular level, the hole structure containing lithium ions on the cathode and anode will gradually collapse and block. From a chemical point of view, it is the active passivation of the positive and negative electrode materials, and the side reactions to form stable other compounds. Physically, the cathode material will gradually peel off, which ultimately reduces the number of lithium ions in the battery that can move freely during charging and discharging.

Overcharging and over-discharging will cause permanent damage to the positive and negative electrodes of lithium-ion batteries, and from the molecular level, it can be intuitively understood that over-discharge will lead to the excessive release of lithium ions from the negative electrode carbon and make its sheet structure collapse, and overcharging will shoehorn too many lithium ions into the negative carbon structure, so that some of the lithium ions can no longer be released.

The unsuitable temperature will trigger other chemical reactions inside the lithium-ion battery to form compounds that we do not want to see, so many lithium-ion batteries have a protective temperature-controlled separator or electrolyte additives between the positive and negative electrodes. When the battery heats up to a certain level, the composite film hole is closed or the electrolyte is denatured, the internal resistance of the battery increases until the circuit is broken, and the battery no longer heats up, ensuring that the battery charging temperature is normal.