Lithium-ion batteries are currently present in most portable electronic devices and their use is rapidly growing in the field of electric vehicles and renewable energy storage. Many components in lithium-ion batteries are toxic and/or environmentally hazardous. Furthermore, some of them are expensive and listed as critical materials in terms of supply-chain risk. Therefore, the need to improve the recycling techniques for lithium-ion batteries is becoming a priority.
Herein, we describe and present a model for the electrodialytic treatment of disposed lithium-ion batteries. Electrodialysis is a separation process based on the use of electric fields and ion-selective membranes. The electrodialytic cell can be designed in different configurations, to enhance the selective extraction of the target products. In a standard electrodialytic cell, the treated matrix is separated from the anode and the cathode compartments by means of anion- and cation-exchange membranes respectively. However, depending on the ionic charge and the specific chemistry of the matrix, different cell designs can be used.
In the present work, different possible configurations are explored for the optimization of the extraction of key valuable components from spent lithium-ion batteries, taking into account the chemical properties of the system depending on the chosen extracting agent and cell configuration. The model presented here is based on a set of differential and algebraic equations consisting of a Nernst-Planck based continuity equations for each of the chemical species involved in the process, coupled with the electroneutrality and the local chemical equilibrium conditions.
The numerical solution is performed using COMSOL Multiphysics, and the simulation results are compared with experimental data for model validation.
