Abstract:Lithium-ion batteries offer several advantages, including high operating voltage, high energy density, fast charge and discharge rates, excellent cycle stability, and lightweight design. These attributes make them widely used in electronic devices, electric vehicles, and other applications. LiNixCoyMnzO2 lithium-ion battery (NCM LIB) are particularly favored for their higher theoretical energy density, gaining significant market attention. However, the layered structure of the NCM cathode material is inherently unstable, causing battery performance to degrade after repeated charge-discharge cycles. Moreover, spent NCM LIB contain valuable strategic metals such as nickel, cobalt, and lithium, as well as organic components like separators, electrolytes, and binders. Improper disposal of these materials results in a resource wastage and an environmental pollution. This study focuses on the combination of various components of spent NCM LIB, examining the composition of pyrolytic products during the pyrolysis process. The research reveals the compositional patterns of pyrolytic products derived from the thermal decomposition of different battery components. Based on the analysis of the composition and distribution of these pyrolysis products, a pretreatment and recovery strategy for spent NCM LIB was proposed, facilitating the recovery of both organic and inorganic materials within the battery cell. The main conclusions are as follows: During the pyrolysis process, organic matter volatilizes or decomposes, with the electrolyte having a relatively low volatilization temperature, ranging from 150 °C to 200 °C. As the pyrolysis temperature is increased to 450 °C, the electrolyte, separator, and binder undergo bond cleavage, cracking, and recombination. This results in the formation of the first long-chain hydrocarbons, alcohols, and esters, such as C4H8O3, C11H22, C17H34, and C10H22O, which exist in the form of pyrolysis oil. These long-chain organic compounds undergo further pyrolysis, producing small molecular gases such as CO2, CH4, C2H6, C2H2, and C3H6. As a result, the pyrolysis gas acquires the ability to reduce the cathode material. The inorganic substances in the battery are present in the pyrolysis residue. During the pyrolysis process, the cracking of the binder facilitates the dissociation of the electrode materials, enabling the separation of the black powder from the Cu-Al current collector. Multi-component pyrolysis enhances the reduction of the cathode materials, which can be attributed to the reductive pyrolysis gases. Among these, the pyrolysis products of the separator play a key role in the reduction reaction. A recycling strategy for spent NCM LIB based on pyrolysis technology was developed to achieve the stepwise recovery of all battery components. The electrolyte is regenerated through low-temperature volatilization and condensation. At elevated temperatures, the separator and binder decompose into long-chain hydrocarbons and alcohols, which exist as pyrolysis oil and can be utilized as fuel for energy supply. These long-chain hydrocarbons and alcohols are further decomposed into small molecular reductive pyrolysis gases. Copper and aluminum powders, as well as black powder, can be obtained by separating the resulting pyrolysis residue. Additionally, nickel, cobalt, manganese, and lithium chemicals can be extracted through wet separation processes such as acid leaching and extraction, without the need for reducing agents. This study presents a novel approach for the pyrolysis and mass recovery of ternary lithium batteries.