A laser-enabled low carbon emission pyrometallurgical approach to recycle Li-ion batteries via silicothermic reductions

In response to the growing shift from graphite to silicon in Li-ion battery anodes, we propose a novel low-carbon pyrometallurgical recycling method that uses silicon as the reducing agent. Silicon was chosen as the reductant because, as the emerging high-capacity anode material, it not only integrates seamlessly with next-generation battery chemistries but also offers a substantially lower carbon footprint than conventional carbon-based reducing agents. The thermodynamics and reaction mechanism between LiCoO 2 and Si are investigated using differential thermal and thermogravimetric analyses. The reaction products are characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and X-ray diffraction. When heated to 1500 °C, LiCoO 2 undergoes simultaneous decomposition and melting, reacting with Si to produce cobalt spheres. Through a laser-enabled recycling process for only 30 s with a laser power of 2 kW, LiCoO 2 is reduced via silicothermic reaction to a Co–Si alloy with only a small amount of slag (Li 2 SiO 3 and Li 2 Co(SiO 4 )). This successful use of silicon paves the way for a cleaner, more sustainable battery recycling strategy. • Developed a low-carbon emission battery recycling process via silicothermic reduction. • Achieved laser-enabled recycling in just 30 seconds. • Products from laser recycling include metallic Co-Si alloy and silicates. • Proposed a reaction mechanism for silicothermic reduction.