Abstract: High-power and fast-discharging lithium-ion battery, which can be used in smart power grids, rail transits, electromagnetic launch systems, aerospace systems, and so on, is one of the key research directions in the field of lithium-ion batteries and has attracted increasing attention in recent years. To obtain lithium-ion batteries with a high power density, the cathode materials should possess high voltage and high electronic/ionic conductivity, which can be realized by selecting high-voltage materials and modifying them to improve the voltage and reduce the battery’s internal resistance. Currently, the cathode materials of high-power lithium-ion batteries mainly include high-voltage LiCoO₂, LiN_i0.5Mn_1.5O₄, and Li(NiCoMn)O₂ materials. Meanwhile, the anode materials include carbon- and Ti-based materials and metal oxides. This paper reviews the research on the modification of these materials, such as element doping and surface coating, which have gained considerable attention nowadays, as well as some new types of anode materials that exhibit excellent electrochemical properties. In terms of the negative electrode, the prelithiation process is one of the effective means to improve the power performance of a lithium-ion battery. This process’s significance is to compensate the consumption of Li⁺ and reduce the potential of the negative electrode to the working range for improving the platform voltage of the battery and improving the power density and energy density. This paper summarizes several commonly used prelithiation methods of the lithium-ion battery. Finally, the lithium salts, solvents, and additives for the electrolytes of lithium-ion batteries are introduced on the basis of their classification, properties, and performances. Several new types of lithium salts and additives are mentioned herein, such as lithium bis(fluorosulfonyl)imide, lithium bis(oxalate)borate, and tetramethylene sulfone. Furthermore, this paper summarizes several common power density test methods of lithium-ion batteries and prospects the research of high-power lithium-ion batteries. As a matter of fact, the power performance of lithium-ion batteries is gaining increasing attention and has truly achieved considerable improvement in recent years.