Recycling spent lithium ion battery as sustainable carbon sources of high-performance Si/C composites anodes

The schematic of charge-disassemble-oxidize-leach approach to recycle graphite and prepare Si/C composite. • Develop a charge-disassemble-oxidize-leach method to recover graphite from spent lithium ion battery anodes. • Demonstrate unique characteristics of recycled graphite at various SOC. • Demonstrate capacity for recycled graphite comparable to commercial graphite anode. • Use the recycled graphite as carbon source to prepared high performance Si/C composite anode. With the rapid development of electric vehicles, the harmless treatment and recycling of lithium ion battery packs have become the current research focus. This work developed a charge-disassemble-oxidize-leach method to recover spent lithium ion battery anodes to prepare recycled graphite (RG). The battery packs were charged at various state of charge (SOC), followed by safe disassembly, oxidization and leach to recover graphite from the anodes. SEM images showed the layered structure of recycled graphite after treatment; Raman spectroscopy and XRD pattern indicated the RG had more defects when charged to 100 % SOC. The RG showed 319.54 mAh·g −1 discharge capacity when cycled under 0.1C for 100 cycles. The RG material was then prepared into Si/C composite anode with silicon nanoparticles via high energy energy ball milling, and showed discharge capacity at 0.1C over 100 cycles at 430.67 mAh·g −1 , which was 34.78 % higher than that of RG alone. CV analysis also suggested characteristic charge and discharge behavior for silicon and graphite in the composite. This method provided a new approach for the future recycling and reusing of spent lithium ion battery anodes.