Spent Li-ion batteries(LIBs) cathodes possess high recycling value. To improve subsequent recovery efficiency and product purity, separating the cathode materials from the aluminum foil is critical. However, traditional separation methods are characterized by high energy consumption, low recycling efficiency, and environmental pollution. This research presents a novel method that involves injecting Joule heat directly into the aluminum foil in the air, resulting in the melting and slight thermal decomposition of the PVDF binder, which reduces its adhesive properties. Owing to the difference in thermal expansion coefficients between the binder and aluminum foil, an instantaneous thermal stress was generated at the interface of the cathode materials and aluminum foil, resulting in a peeling force. This method enabled a rapid and efficient separation of lithium iron phosphate (LFP) and ternary Li-ion (NCM) battery cathode materials. The optimal separation conditions, separation mechanism, and properties of the recovered products were investigated thoroughly using high-speed camera imaging, temperature rise calculations, and microscopic characterization. This chemical-free method avoids the generation of wastewater and gas emissions. Under optimal experimental parameters, the separation efficiency and purity of cathode material reached 99 % and 99.7 %, respectively. Additionally, this method preserves both the structural integrity of the aluminum foil and the crystalline structure of the cathode materials, offering a new pathway for sustainable recycling of end-of-life LIBs.

中文翻译：

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通过快速焦耳加热实现锂离子电池正极材料和集流体的高效环保分离和回收

废旧锂离子电池（LIB）正极具有很高的回收价值。为了提高后续的回收效率和产品纯度，将正极材料与铝箔分离至关重要。然而，传统的分离方法存在能耗高、回收效率低、污染环境的特点。这项研究提出了一种新颖的方法，将焦耳热直接注入空气中的铝箔，导致PVDF粘合剂熔化并轻微热分解，从而降低其粘合性能。由于粘合剂和铝箔之间的热膨胀系数差异，正极材料和铝箔的界面处产生瞬时热应力，从而产生剥离力。该方法能够快速有效地分离磷酸铁锂（LFP）和三元锂离子（NCM）电池正极材料。使用高速相机成像、温升计算和微观表征，彻底研究了最佳分离条件、分离机制和回收产物的性质。这种无化学方法避免了废水和气体排放的产生。在最佳实验参数下，正极材料的分离效率和纯度分别达到99%和99.7%。此外，该方法保留了铝箔的结构完整性和正极材料的晶体结构，为报废锂离子电池的可持续回收提供了新途径。