State Key Laboratory of Environmental Criteria and Risk Assessment, Chinese Research Academy of Environmental Sciences, Beijing 100012, China; National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China.
National-Regional Joint Engineering Research Center for Soil Pollution Control and Remediation in South China, Guangdong Key Laboratory of Integrated Agro-environmental Pollution Control and Management, Institute of Eco-environmental and Soil Sciences, Guangdong Academy of Sciences, Guangzhou 510650, China; Key Laboratory of Pollution Ecology and Environmental Engineering, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China.
Waste Manag. 2024 Jun 15;182:186-196. doi: 10.1016/j.wasman.2024.04.021. Epub 2024 Apr 25.
Current Li-ion battery (LIB) recycling methods exhibit the disadvantages of low metal recovery efficiencies and high levels of pollution and energy consumption. Here, products generated via the in-situ catalytic pyrolysis of bamboo sawdust (BS) were utilized to regulate the crystal phase and nanoscale size of the NCM cathode to enhance the selective Li extraction and leaching efficiencies of other valuable metals from spent LIBs. The catalytic effect of the NCM cathode significantly promoted the release of gases from BS pyrolysis. These gases (H, CO, and CH) finally transformed the crystal phase of the NCM cathode from LiNiCoMnO into (Ni-Co/MnO/LiCO)/C. The size of the spent NCM cathode material was reduced approximately 31.7-fold (from 4.1 μm to 129.2 nm) after roasting. This could be ascribed to the in-situ catalytic decomposition of aromatic compounds generated via the primary pyrolysis of BS into C and H on the surface of the cathode material, resulting in the formation of the nanoscale composite (Ni-Co/MnO/LiCO)/C. This process enabled the targeted control of the crystal phase and nanoscale size of the material. Water leaching studies revealed a remarkable selective Li extraction efficiency of 99.27 %, and sulfuric acid leaching experiments with a concentration of 2 M revealed high extraction efficiencies of 99.15 % (Ni), 93.87 % (Co), and 99.46 % (Mn). Finally, a novel mechanism involving synergistic thermo-reduction and carbon modification for crystal phase regulation and nanoscale control was proposed. This study provides a novel concept for use in enhancing the recycling of valuable metals from spent LIBs utilizing biomass waste and practices the concept of "treating waste with waste".
目前的锂离子电池（LIB）回收方法存在金属回收率低、污染和能耗高的缺点。在这里，利用竹屑（BS）原位催化热解产生的产物来调节 NCM 正极的晶体相和纳米级尺寸，以提高从废旧 LIB 中选择性提取和浸出其他有价值金属的效率。NCM 正极的催化作用显著促进了 BS 热解产生的气体的释放。这些气体（H、CO 和 CH）最终将 NCM 正极的晶体相从 LiNiCoMnO 转化为（Ni-Co/MnO/LiCO）/C。经过煅烧，废旧 NCM 正极材料的尺寸缩小了约 31.7 倍（从 4.1μm 缩小到 129.2nm）。这归因于 BS 初次热解产生的芳香族化合物在正极材料表面原位催化分解为 C 和 H，从而形成纳米级复合材料（Ni-Co/MnO/LiCO）/C。该过程实现了对材料晶体相和纳米尺寸的靶向控制。水浸出研究表明，Li 的选择性提取效率高达 99.27%，浓度为 2M 的硫酸浸出实验表明，Ni 的提取效率高达 99.15%，Co 的提取效率高达 93.87%，Mn 的提取效率高达 99.46%。最后，提出了一种协同热还原和碳改性的新机制，用于调节晶体相和纳米控制。该研究为利用生物质废物增强废旧 LIB 中有价值金属的回收提供了一个新的概念，并实践了“以废治废”的概念。
