Direct capacity regeneration for spent Li-ion batteries

With the rapid increase in lithium (Li)-ion battery applications, there is growing interest in the circulation of large quantities of spent batteries. However, existing recycling systems require not only several processes for recycling itself but also remanufacturing processes, which require increased energy consumption. Here, a recovery reagent injection is proposed for regenerating spent batteries. For capacity-degraded batteries with reduced electrons and carrier Li+ ions, Li-naphthalene radical anions with controlled potential based on solvent dielectric effects are injected, selectively providing both electrons and carrier Li ions to the cathode and resulting in capacity recovery without degradation with cycles. Furthermore, the integration of constant-voltage treatment has successfully demonstrated a high-capacity recovery effect in 4 Ah-class practical batteries. The proposed method is expected to achieve the shortest route in battery regeneration and provide new options for circular battery systems.