An ultra-fast reaction process for recycling lithium ion batteries <i>via</i> galvanic cell interaction

The efficient realization of a closed-loop process is an ultimate goal for reusing spent lithium-ion batteries (LIBs), yet the complicated recycling processes of leaching and purification in an acid atmosphere are totally different compared with the regeneration method of the cathode precursor in alkali solution, inevitably resulting in the redundant consumption of acid/ammonia solutions and increased burden for a green environment. Herein, considering the advantages of selective extraction and similar chemical surroundings for recovery and regeneration, ammonia-leaching has been proposed to achieve short-process closed-loop recycling with effective impurity removal. Particularly, benefiting from the galvanic cell interaction, the sluggish reaction rate and relatively harsh reaction conditions of ammonia-leaching are well addressed. High leaching efficiency can be achieved within 10 min, where nearly 80% valuable metals are extracted in the initial 1 min. Notably, this leaching solution, after purification, can be used to directly synthesize the cathode precursor through the commercial alkali co-precipitation method. This process is superior to the acid leaching system, which requires the use of acid-base solutions back and forth to adjust pH for metal extraction and material regeneration. Compared to the traditional solid-to-liquid reaction with a shrinking core model, the solid-to-solid reaction with galvanic cell interaction substantially addresses the inherent issue of sluggish leaching efficiency, exhibiting much stronger competitiveness in the leaching rate and environment cost. Thus, it provides prospects to achieve large-scale recycling and regeneration of spent LIBs simultaneously in the whole-process alkali-atmosphere.