Natural small molecule-based recoverable polymer binders for intact and efficient recycling of lithium-ion batteries

As an indispensable part of the battery, the binder plays an important role in maintaining the structural integrity of the battery electrode and improving its electrochemical performance. Conventional polyvinylidene fluoride (PVDF) binders are particularly difficult to remove during the recycling of waste batteries because of their strong chemical stability, which not only markedly increases the recycling cost but also generates a large amount of fluorine-containing waste gas that pollutes the environment. In this study, a recoverable polymer binder (LM) with excellent self-healing properties, adhesion, and long-lasting stability was prepared for lithium-ion batteries using a simple heating polymerization method based on the natural small molecule α-lipoic acid (LA). The batteries assembled with LM exhibited excellent long-term stable performance at a high rate. After 920 cycles of charging and discharging at 1.0 C, the specific capacity was maintained at 80 %, while the battery assembled with PVDF only provided 524 cycles under the same conditions. More importantly, LM can be easily removed using a pH-control method to realize intact and efficient recycling of lithium iron phosphate (LFP) active material. This strategy opens a new path for the efficient recycling of large-scale energy storage batteries.