The key technologies to be developed in REVITALISE include innovative pre-treatment, direct recycling and hydrometallurgy. The target is that 40% of pre-treated input materials will be suitable for direct recycling and the rest will be fed to hydrometallurgical processing. The pre-treatment targets scrap coating (scraps produced during battery production) and EOL batteries. To produce materials available for direct recycling, clean separation of battery components is warranted through physical separation and delamination, electrohydraulic fragmentation, ultrasonication, magnetic and electrostatic separation techniques, which are being developed and tested.
Battery components targeted in direct recycling test include graphite, NMC, LFP and Na-ion battery cathode. NMC cathodes have been successfully purified through organic leaching and regenerated by relithiation. Prussian white cathode has been successfully purified by ice-stripping process and regenerated by resodiation. Graphite has been successfully regenerated through coating process. Electron microscopy and X-ray diffraction combined with electrochemical characterization confirmed the success in battery component regeneration.
Two hydrometallurgical processes are being developed: mild leaching based process for the recovery of Li and acid leaching based process for total metal recovery. In the former case, water leaching based process has been tested at lab scale leading to 92% pure Li2CO3 with Li recovery rate of 90%. For total recovery, leaching tests with different inorganic acids (HCl, HNO3 and H2SO4) on different black mass chemistries (NMC 111, NMC 622, NMC 901 and LFP) show HCl as the acid of choice for high leaching efficiencies. Further, leaching performance of HCl was not affected by black mass chemistry. This means HCl based process can deal with the black mass cross contamination (black mass mixture). Several organic acids such as acetic, oxalic and citric acids have been tested to recover valuable metals from black mass. In the case of Na-ion battery, several organic and inorganic chemicals have been screened for leaching. All these flowsheets are being currently tested at lab scale, before providing inputs for life cycle analysis, techno-economic analyses and the likes.