A green and facile pretreatment for flotation separation of electrode materials from spent lithium-ion batteries: Low-temperature roasting-induced deformation of PVDF

The rapid growth of lithium-ion batteries (LIBs) in recent years has produced a large number of spent LIBs that need to be recycled urgently. The effective separation of cathode active materials from spent LIBs by froth flotation is an important step in the recovery process. Herein, the low-temperature roasting pretreatment is used to change the surface wettability of electrode material particles to achieve the efficient flotation separation of cathode material and graphite. The phase composition, surface morphology and surface wettability of the roasted electrode materials were systematically investigated, and the variation of polyvinylidene fluoride (PVDF) binder with temperature was observed by atomic force microscopy and investigated by molecular dynamics simulation. After roasting at 350 ℃, a large number of hydrophilic sites are exposed on the surface of the cathode material due to the condensation of PVDF, and after intensive flotation by carboxymethyl cellulose, the grade of cathode active material reached 94.02 %. It is worth noting that PVDF does not decompose at the used temperature for LIBs recycling, which can save energy and prevent the release of fluoride and other gases into the environment. It is believed that the provided idea has reference meaning for the efficient and sustainable recycling of LIBs.