This study explores a novel solvent-based delamination method that employs a mixture of triethyl phosphate (TEP), acetone, and carbon dioxide (CO₂) under pressure and temperature for the efficient and fast direct recycling of positive electrode production scraps. Optimization of experimental conditions led to achieve 100% of delamination within 15 min at 120 °C and 100 bar, with a low solvent consumption of 1.5 of TEP to electrode ratio (w/w). The CO₂ allows decreasing the viscosity of the TEP and acetone mixture and so increasing its diffusivity; favoring the binder dissolution and accelerating the delamination process versus other reported processes. This original approach not only enables the reduction of solvent consumption (by 6.7×), but removes the need for stirring, which is often detrimental to solvent-based approaches for scaling up the process while maintaining 100% of delamination. Subsequent to the delamination process, the active material LiNi_0.6Mn_0.2Co_0.2O₂ (NMC622) in powder form was easily and fully separated from the current collector, enabling a comprehensive characterization. A more in-depth focus on the electrochemically active material revealed that its chemical composition, crystal structure, and microstructure remained preserved throughout the recycling process. Ultimately, the electrochemical performance of the recycled NMC622 closely resembled that of the pristine NMC622, affirming the promising potential of this approach.

中文翻译：

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使用加压 CO2 直接回收锂离子电池正极生产废料的工艺


本研究探索了一种新型的基于溶剂的分层方法，该方法在压力和温度下采用磷酸三乙酯 （TEP）、丙酮和二氧化碳 （CO ₂ ） 的混合物，以高效、快速地直接回收正极生产废料。优化实验条件后，在 120 °C 和 100 bar 下，在 15 分钟内实现 100% 的分层，溶剂消耗量低至 1.5 TEP 与电极比 （w/w）。CO ₂ 可以降低 TEP 和丙酮混合物的粘度，从而增加其扩散性;与其他已报道的工艺相比，有利于粘合剂溶解并加速分层过程。这种原始方法不仅可以减少溶剂消耗（减少 6.7×），而且无需搅拌，这通常不利于基于溶剂的方法扩大工艺规模，同时保持 100% 的分层。在分层过程之后，粉末状的活性材料 LiNi _0.6 Mn _0.2 Co _0.2 O ₂ （NMC622） 很容易、完全地从集流体中分离出来，从而能够进行全面的表征。对电化学活性材料的更深入关注表明，其化学成分、晶体结构和微观结构在整个回收过程中保持不变。最终，回收的 NMC622 的电化学性能与原始 NMC622 的电化学性能非常相似，肯定了这种方法的前景。