Innovative Method to Recover Graphite from Spent Lithium-Ion Batteries

Abstract

This paper introduces an innovative approach to efficiently separate anode materials by leveraging the properties of the organic binder found in the anode sheets of spent lithium-ion batteries. Initially, the study investigates the impact of the liquid/solid ratio, treatment temperature, and treatment time on the separation efficiency of anode materials within an aqueous solution system. The underlying reasons influencing the separation efficiency in this system are thoroughly analyzed. Subsequently, a novel method involving the use of a surfactant as a separating agent is proposed to enhance the efficiency of anode material separation. The study explores influencing factors such as the separating agent concentration, temperature, and time. Under optimal conditions, the separation efficiency of the anode material reaches 100%. The results indicate that the solubility of styrenebutadiene rubber (SBR) and carboxymethyl cellulose (CMC) in water gradually decreases with an increase in the liquid−solid ratio in the aqueous solution system, leading to a decrease in the separation efficiency. However, in the surfactant system, the combination of the hydrophilic group in the surfactant molecule and the CMC group in the solution results in surface adsorption, increasing binder molecule solubility and achieving higher separation efficiency, particularly under high liquid−solid ratios. Ultimately, after heat treatment for impurity removal, the anode material achieves a tapped density of 1.06 g/cm 3 . This provides a prelithiated raw material for the further restoration of graphite materials.