A water-soluble binder for recyclable lithium-ion batteries

The substantial growth in the market for lithium-ion batteries has created a huge challenge for their end-of-life management and demands sustainable solutions. Direct recycling is a promising choice due to its superior energy efficiency and environmental benefits, particularly the advantage in preserving the original chemistry and structure of the target materials. However, binders hold the active electrode materials and the current collectors tightly together, and their separation usually involves energy-intensive thermal treatment and environmentally hazardous chemicals. Here we present a water-soluble binder by crosslinking natural sericin protein with sulfuric acid through supramolecular interactions. The as-fabricated binder demonstrates comparable electrochemical performance with the most common polyvinylidene fluoride formulation, when applied to a typical LiNi 1/3 Co 1/3 Mn 1/3 O 2 (NCM111) cathode. A 1.3-Ah pouch cell retained 85.0% of its initial capacity after 500 cycles. Equally importantly, after being soaked in water at 50 °C for less than 1 min, the NCM111 and graphite can be completely detached from the current collectors for recycling. By integrating the circular economy into the battery design, this work paves the way for the development of next-generation battery chemistries with enhanced sustainability.