Energy-storage long-cycle-life lithium ion battery and preparation method thereof

The invention discloses an energy-storage long-cycle-life lithium ion battery and a preparation method thereof, and relates to the technical field of lithium ion batteries. Preparing a total electrolyte; the electrolyte is injected twice, and the first electrolyte used in the first injection accounts for 80-90% of the total electrolyte; the second electrolyte used in the second liquid injection accounts for 10-20% of the total; and assembling the negative plate, the total electrolyte, a positive plate and a diaphragm to obtain the energy-storage long-cycle-life lithium ion battery. According to the energy-storage long-cycle-life lithium ion battery and the preparation method thereof, graphite prepared from an isotropic coke source is adopted in the aspect of a negative electrode material so as to obtain better cycle performance, meanwhile, a PAA binder is added to relieve the expansion phenomenon in the graphite cycle process, then the VC content is increased through secondary liquid injection, and the cycle