The forefront of current lithium-ion battery technology in various electronic applications concerns the enormous e-waste that gives rise to end-of-life batteries. Resource sustainability of battery-grade graphite, non-biodegradable polymeric separator, and ever-growing lithium-ion battery manufacturing cost extend a strong impetus for lithium-ion battery recycling. Herein, we report an effective strategy to upcycle the waste separator to valuable carbon. The recycle separator derive carbon is turbostratic with the simultaneous presence of an order-disorder phase. The carbon anode electrochemically delivers 695 mAh g−1 capacity at 100 mA g−1, which is double the capacity of the recover graphite anode (300 mAh g−1). Despite the significant electrochemistry, the poor conversion efficiency and low product yield after carbonization may impede large-scale implementations. However, the Li-ion storage capability of recycle separator derive carbon, in minimal quantity, enhances the capacity of the recycled graphite. The composite of recycle graphite and recycle separator derive carbon outperforms the capacity of recycled graphite with higher Li-ion diffusivity. It delivers a stable discharge capacity of 380 mAh g−1 at a 0.5C rate over 1200 cycles (285 mAh g−1 for recycled graphite). This study entails sustainable recycling of spent separators and boosts the efficiency of recycled graphite for high-performance lithium-ion batteries. © 2023 Elsevier B.V.