The application discloses a high-energy-density
lithium ion battery, which comprises a positive
electrode sheet and a negative
electrode sheet, the positive
electrode sheet comprises a positive electrode active material, the positive electrode active material comprises a
lithium iron phosphate material and a
lithium-rich material, the
mass ratio of the lithium-rich material in the positive electrode active material is 0.2%-8%, and the
chemical formula of the
lithium iron phosphate material is Li 1+x Fe 1‑ y M y (PO4) 1+z , 0<=x<0.1, 0<=y<0.01, 0<=z<0.04, M comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, the lithium-rich material comprises at least one of LFO and LNO, the
chemical formula of the LFO is Li 5+a Fe 1‑b Z b O 4+c , 0<=a<0.5, 0<=b<0.01, 0<=c<0.03, Z comprises at least one of Ti, V, Zr, Nb, Mg, Mo, W and Al, and the
chemical formula of the LNO is Li 2+d Ni 1‑ e Y e O 2+f , -0.5<=d<=0.5, e>=0, -0.5<=f<=0.5, Y comprises at least one of Ti, V, Al, Mg, Mn and Fe, and the negative electrode active material comprises a
silicon negative
electrode material, the
mass ratio of the
silicon negative
electrode material in the negative electrode active material is 1%-50%. The application has the advantages of improving the
energy density, rate performance and cycle performance of the
lithium battery.