High-efficiency core-shell magnetic heavy-metal absorbents derived from spent-LiFePO₄ Battery

Search for simple and efficient recycling methods to utilize spent lithium-ion batteries is crucial for achieving sustainable resource development and reducing the hazardous materials released from the spent batteries. Herein, we have developed a new strategy to utilize the spent LiFePO₄ batteries by utilizing the cathode plate as raw material to synthesize mesoporous core-shell adsorbent Mm@SiO₂ (Mm denoted as the magnetic material) through a simple alkaline leaching process. The as-converted material exhibits excellent adsorption capacity when it has been used to remove heavy metal ions in heavy metal polluted water. The adsorption capacities for Cu²⁺, Cd²⁺, and Mn²⁺ have been achieved up to 71.23, 80.31 and 68.73 mg g^-1, respectively. The detailed adsorption mechanism has been elucidated with comprehensive characterization techniques, including TEM, XPS, NEXAS, and EXAFS, the edge shared [Cu₂O₈] bipyramids can be fit against the EXAFS data to represent the atomic-scale local structure after Mm@SiO₂ adsorbs Cu²⁺. The present work demonstrates a novel routine to reutilize the spent lithium batteries, which is of great importance to achieve sustainable development based on the "waste-to-treasure" and "waste-to-control-waste" strategy for simultaneously reducing the hazardous release from industrial solid waste and heavy metal polluted water.