| 摘要: | 面對日益嚴峻的能源與環境問題，鋰離子電池（LIBs）的回收與再利用成為實現循環經濟與永續發展的重要議題。本研究以廢棄NCM正極材料作為出發點，採用環境友善的檸檬酸進行亞臨界濕法浸出，有效回收其中之Ni、Co、Mn等高價值金屬離子，並進一步將其轉化為水電解析氧反應（Oxygen Evolution Reaction, OER）之高效催化劑，研究中分別利用水熱法與真空雷射鹽類還原技術（pulsed vacuum laser metal salt, PLMS）合成FeNiCoMn多金屬催化材料，並將其應用於鹼性條件下之電化學測試與陰離子交換膜水電解系統（Anion Exchange Membrane Water Electrolysis, AEMWE）中。
實驗結果顯示，在最適化浸出條件下，濃度1M的檸檬酸、反應溫度160℃、反應時間4小時、固液比30g/L，可實現Li、Ni、Co、Mn金屬離子高達94%以上的浸出效率；使用PLMS合成之催化劑能展現出優異的電化學性能，在1 M KOH中展現低的OER過電位與500小時長時間穩定的反應表現。應用於AEMWE系統時，在2V操作電壓下可以實現629.2mA/cm²的高電流密度，進一步的ICP與XRD分析指出，PLMS製程相較於水熱法在元素比例控制與晶體結構均勻性上更具有優勢，能進一步提升催化活性與穩定性。此外，本研究也進行了成本與碳排放的評估，發現回收製程可分別降低催化劑製備成本約20-22%、減少碳排放達34.9%，本研究證明廢棄鋰電池正極材料不僅能有效回收，同樣具有潛力轉化為高效能的電催化材料，達到資源回收、能源轉換與永續發展三者兼顧之目標。
;In response to increasingly severe energy and environmental challenges, the recycling and reuse of lithium-ion batteries (LIBs) have become critical topics for achieving a circular economy and sustainable development. This study focuses on the sustainable recovery of discarded NCM cathode materials, employing citric acid ,a green and environmentally friendly leaching agent under subcritical hydrometallurgical conditions to effectively extract high-value metal ions such as Ni, Co, and Mn. These recovered metals were subsequently transformed into efficient oxygen evolution reaction (OER) electrocatalysts. Two synthesis methods were adopted: hydrothermal synthesis and pulsed vacuum laser metal salt (PLMS) reduction, to fabricate FeNiCoMn multi-metallic catalysts. The resulting materials were tested for their electrocatalytic performance under alkaline conditions and in an anion exchange membrane water electrolysis (AEMWE) system.
Experimental results indicate that under optimized leaching conditions 1M citric acid, 160 ℃ reaction temperature, 4 hour duration, and a solid-to-liquid ratio of 30 g/L over 94% leaching efficiency was achieved for Li, Ni, Co, and Mn ions. The PLMS-derived catalyst demonstrated excellent electrochemical performance, with an OER overpotential as low in 1M KOH and stable operation for up to 500 hours. When applied in an AEMWE system, the catalyst achieved a high current density of 629.2 mA/cm² at an operating voltage of 2V. Further ICP and XRD analyses revealed that the PLMS process provided superior control over elemental ratios and enhanced structural uniformity compared to the hydrothermal method, contributing to improved catalytic activity and stability.Additionally, cost and carbon footprint assessments showed that the recycling-based process reduced catalyst production costs by approximately 20-22% and carbon emissions by 34.9%. This study demonstrates that waste LIB cathode materials can not only be effectively recovered but also transformed into high-performance electrocatalysts, simultaneously addressing resource recovery, energy conversion, and sustainability goals. |
