A Multifunctional Lithium Amide Salt for Circular Battery Recycling

Electrolyte instability is an intrinsic issue that curtails the cycle life of lithium-ion batteries in energy storage devices. Residual trace moisture inevitably induces LiPF6 hydrolysis, generating aggressive hydrofluoric acid (HF) during cycling, which degrades the cathode-electrolyte interphase (CEI) and accelerates solvent decomposition, thereby decreasing ionic conductivity and escalating interfacial impedance. Herein, we develop a multifunctional lithium trifluoro-N-methylacetamide (LiTFMA) salt to scavenge residual moisture and HF via a thermodynamic mechanism, thereby rejuvenating the ionic conductivity and lithium-ion transference number of degraded electrolytes. Furthermore, TFMA– anions derive a thin and uniform nitrogen-containing CEI, which renovates degraded interphases and suppresses transition-metal dissolution. Consequently, retired NCM811 electrodes remanufactured with the LiTFMA-regenerated electrolyte deliver a capacity retention exceeding 80% after 300 cycles. This dual-functional strategy upcycles hazardous spent electrolytes into high-performance functional components, establishing a scalable pathway toward a circular battery economy.