In recent years, the demand for lithium-ion batteries (LIB) has grown rapidly, but many basic elements in the positive electrode, such as lithium, cobalt, and nickel, are expensive and heavily dependent on imports. At present, most hydrometallurgical leaching methods are based on the use of an “in/organic acid+H₂O₂” system, but there are environmental pollution, safety hazards, and efficiency issues. Therefore, this study proposes a new environmentally friendly, safe, and efficient leaching process using malonic acid and ascorbic acid as leaching and reducing agents. Under the optimal conditions: malonic acid concentration of 0.4 mol/L, ascorbic acid concentration of 0.2 mol/L, solid-liquid ratio of 30 g/L, leaching temperature of 50 ℃, and leaching time of 50 minutes; the leaching rates of lithium, nickel, cobalt, and manganese are all more than 95%. The kinetic fitting validation results indicate that the leaching process conforms to the “shrinking core model” and the apparent activation energy is lower than the previous values of “organic acid+H₂O₂”; therefore, the addition of ascorbic acid can effectively promote the leaching of valuable metals from positive electrode materials with malonic acid, thereby improving the leaching efficiency; the infrared spectrum and XRD results indicate that the coordination form between malonic acid and transition metals during the leaching process is C₃H₂O₄M (M is transition metals Ni, Co, Mn).