Formation method for preparing a fast-charging lithium ion cell

A method of preparing a fast-charging lithium ion cell, the method comprising:

• forming a solid-electrolyte interphase (SEI) in the anode by:
• performing a first formation cycle of charging the cell to between 30 and 70% of a full cell capacity and then discharging the cell, and
• performing, consecutively, a plurality of charge-discharge formation cycles, in which the cell is charged to 80% of the full cell capacity and then discharged, in each of said plurality of charge-discharge formation cycles.

A method of preparing a fast-charging lithium ion cell for use, the method comprising:

• forming a solid-electrolyte interphase (SEI) in the anode by:
• performing at least a first formation cycle of fully charging the cell and then discharging the cell, wherein a charging current in the first formation cycle is gradually increased during the first formation cycle, from under 0.02 C to over 0.3 C.