Efficient liberation of electrode materials in spent lithium-ion batteries using a cryogenic ball mill

Efficient liberation is a key to the recycling of the electrode materials in spent lithium-ion batteries (LIBs). To improve the liberation of the electrode materials, a novel cryogenic grinding method of high selectivity was proposed. The low temperature characteristics of the traditional binder material PVDF and the current collector materials were tested. The results show that the glassy transition temperature of the binder PVDF is about 235 K. The binder would change from a high elastic state to a brittle state thus is easy to be crushed at a lower temperature. On the contrary, the impact strength of the current collector materials increases with the decrease of the temperature. Therefore, the grinding of electrode plates at low temperatures would be more selective grinding. The cryogenic grinding tests results show that, compared with that of room temperature, the content of the nickel-cobalt-manganese-lithium in the −0.15 mm particle size was increased from about 16–84%, the graphite content from 31.55% to 90.58%, and the content of aluminum and copper in the +1 mm grain size increased from 79.32% and 74.62–95.42% and 97.75%，respectively. This research may provide a new method to the recycling of spent LIBs.