GO/PbO ₂ Composite with Heterostructure for Electrocatalytic Degradation of Ethylene Carbonate in Spent Lithium-Ion Batteries

Electrocatalytic oxidation offers an efficient and environmentally compatible strategy for the treatment of organic waste. To mitigate the ecological risks caused by the discharge of organic electrolytes from spent lithium-ion batteries, the development of high-performance electrode materials is of great importance. Herein, we fabricate three graphene oxide (GO)/PbO₂ composite electrodes: GO-PbO₂-50, GO-PbO₂-100, and GO-PbO₂-150, for the electrocatalytic oxidation of ethylene carbonate (EC) that is the main organic electrolyte in spent lithium-ion batteries. The formation of a GO/β-PbO₂/α-PbO₂ heterostructure decreases the β-PbO₂ crystal size, increases active sites, enhances ·OH radical generation, reduces interfacial charge transfer resistance, and elevates the oxygen evolution potential. GO-PbO₂-100 electrode exhibits the best catalytic activity, achieving almost complete mineralization of 1000 mg L^-1 EC to CO₂ and H₂O under a current density of 40 mA cm^-2. The electrochemical degradation of EC adheres to pseudo-first-order kinetics. Density functional theory calculations confirm that the GO/PbO₂ composite significantly decreases the Gibbs free energy of each oxidation step, particularly for the rate-determining step, thereby enhancing the reaction spontaneity. Therefore, the GO/PbO₂ composite with a heterostructure is a promising catalyst for the efficient degradation of organic waste in spent lithium-ion batteries.