使用済みLiCoO2のフラッシュアップサイクリングによる高機能電池用酸素抑制型リチウム補充剤への転換

Battery recycling is essential to mitigate resource depletion and improve environmental sustainability. However, conventional metallurgical and direct regeneration methods involve trade-offs among energy input, environmental impact, and feedstock adaptability. Here we report a universal upcycling method that converts spent LiCoO₂ into Li₆CoO₄ within 10 seconds via flash Joule heating, achieving complete lithium and cobalt recovery regardless of degradation state. The resulting Li₆CoO₄ serves as a high-capacity sacrificial additive to offset active lithium loss. To overcome its inherent air sensitivity and oxygen release during delithiation, a conformal sulfur coating was applied to stabilize surface chemistry and redirect oxygen evolution into sulfate formation. This sulfur-mediated mechanism effectively suppresses gas generation and parasitic side reactions, enabling non-destructive lithium replenishment. When integrated into graphite | |LiFePO₄ pouch cells, the stabilized Li₆CoO₄ achieves 91.4% capacity retention over 1400 cycles at a current density of 80 mA g^-1. Comparative life-cycle and techno-economic analyses reveal clear reductions in energy consumption and CO₂ emissions, along with improved economic returns. This work provides a scalable route that bridges positive electrode waste recovery with high-performance lithium supply, advancing closed-loop battery systems for sustainable energy storage.