(714f) Porous-Silicon for Li-Ion Battery Anodes: From Unlocking Formation Pathways to Scaled-up Manufacturing

Silicon has one of the highest specific capacities of all the potential lithium-ion battery anode materials, being able to store almost 10x more charge than the presently used graphite. Despite its huge volumetric expansion, extensive research in the field have shown that damage caused by this expansion can be limited or avoided by using porous silicon (p-Si). Producing p-Si in bulk can be achieved via the magnesiothermic reduction (MgTR), however, it requires high temperatures (>650^oC) to attain meaningful yields [J. Mater. Chem. A, 2018, 6, 18344]. Operating MgTR at such temperatures causes loss of porosity due to sintering, while also requiring uneconomical amounts of energy [J. Mater. Chem. A, 2020, 8, 4938].

We have discovered a process that can produce p-Si at as low as 380°C, with excellent yields and strong performance [RSC Adv., 2021, 11, 35182]. Using in-situ powder XRD studies the Stanford Synchrotron Radiation Lightsource, we mapped for the first time, various pathways through which p-Si formation proceeds [10.26434/chemrxiv-2024-1342w]. We have also investigated the scale-up of p-Si production by exploring the process chemistry and optimising conditions. Finally, extensive technoeconomic analysis showed that p-Si produced from our method will be highly competitive compared to other Si-based anodes [J. Power Sources, 2023, 588, 233720]. Taken together, these results strongly suggesting that our process has the potential to enable the economic and sustainable bulk production of silicon.