Lithium-ion batteries are the primary energy source for modern electric mobility, making the processing of battery waste and the recovery of critical raw materials – particularly lithium, cobalt, manganese, and nickel – a major challenge for sustainable industrial development. The rapidly growing demand for energy storage technologies further intensifies the need for efficient and environmentally benign recycling processes. This study investigates the hydrometallurgical leaching of black mass derived from LCO-type lithium-ion batteries obtained exclusively through manual dismantling and mechanical processing, without any prior thermal or chemical pretreatment. Reductive leaching was performed using a ternary system consisting of sulfuric acid, adipic acid, and hydrogen peroxide at 85°C for one 120 minutes, with a liquid-to-solid ratio of 10. Under these conditions, the leaching efficiencies reached 83.91% for Co, 85.86% for Li, 76.98% for Al, 94.16% for Cu, 58.48% for Ni. The results demonstrate that synergistic organic-acid-based reductive leaching offers a promising alternative for the recovery of valuable metals from polymetallic lithium-ion battery waste, contributing to more sustainable and cleaner recycling practices.