Insight into interaction of electrode particles from spent lithium-ion batteries assisted by pyrolysis

Abstract

Pyrolysis-assisted dispersion for electrode particles from spent lithium-ion batteries (LiBs) is an extremely effective means to improve subsequent recovery efficiency. The relationship between interaction energy and surface properties of electrode particles has been constructed. The XRD results demonstrated that the mineral phases of both anode and cathode particles, mainly composed of graphite and LiCoO2 respectively, had little changes using a pyrolysis process at 550 ℃ for 30 min. Nevertheless, pyrolysis treatment could remove the organic film of electrode particles to alter the surface properties effectively. With the organic film removal by pyrolysis, the subtraction value on the contact angle of cathode and anode particles was increased from 9.3° to 35.44°, while the difference in charge ability was increased from 0.35 mV to 23.21 mV. The interaction energy calculations also illustrated that the electrostatic repulsion energy and hydrophilic repulsion energy both increased significantly, resulting in the total interaction energy of anode and cathode particles being 1.7 and 3.8 times that before pyrolysis. Furthermore, the total interaction energy, which determined the dispersing of electrode particles in suspension, mainly depended on the hydrophilic force. The findings might propose an alternative means for enhancing particle interaction to improve the recycling efficiency of electrode materials from spent LiBs by flotation.