A novel high specific capacity lithium‐ion capacitor battery with Li + ‐doped Ni 0.64 Al 0.64 Mn 0.56 O 2 prepared by coprecipitation method as cathode active material

Summary Lithium‐ion capacitor battery is a late‐model energy storage system. It can combine the lithium‐ion battery with the capacitor to ensure that it has a high specific capacity and excellent large‐current discharge performance. In this paper, a novel Li + ‐doped Ni 0.64 Mn 0.64 Al 0.56 O 2 is synthesized by coprecipitation method and as a capacitor active material with commercialized LiNi 1/3 Co 1/3 Mn 1/3 O 2 in different proportions forms the cathode of the lithium‐ion capacitor batteries. By analyzing the results of physical property characterization, when the mass ratio is 7:3, the crystal size of cathode material is less than 2 μm with uniform porous distribution. And, through electrochemical tests, the cathode has the greatest excellent reversibility, the lowest‐charge resistance, and the fastest‐lithium‐ion diffusion rate. Specific capacity can reach 196.34 mAh g −1 at 0.5°C and, even at 5°C current density, it also can be 67.63 mAh g ‐1 . After 110 times charge and discharge cycles, capacity retention of this cathode material at 5°C still can be over 85%.