The invention discloses a high-energy-density lithium ion battery. The lithium ion battery comprises a positive electrode, a negative electrode, a diaphragm and an electrolyte. The negative electrodecomprises a negative electrode active material, a conductive agent and a binder, the binder comprises a polymer shown in the structural formula I, and the electrolyte contains a fluorine-substituted cyclic carbonate compound shown in the structural formula II. The binder and fluorine-substituted cyclic carbonate are used together so that side effects caused by repeated expansion and contraction ofa SiO/artificial graphite negative electrode can be inhibited more effectively, SiO/artificial graphite active substances, the conductive agent and a current collector are bonded together more firmly, rapid growth of the internal resistance of the battery is inhibited, and therefore the high-temperature cycling performance of the battery is improved.