Constructing cellulose nanofiber / Si composite 3D-Net structure from waste rice straw via freeze drying process for lithium-ion battery anode materials

Silicon is one of the most potential anode materials for next-generation lithium-ion batteries. However, a quick fading occurs during the charging and discharging process due to a large volume expansion. In this work, waste Si from the photovoltaic (PV) industry is applied as the raw materials for fabricating lithium-ion battery anode, and the cellulose nanofibers (CNFs) from waste rice straw is used to protect crack formation. A 3D-net structure of Si/CNF composite is revealed after a freeze-drying process. This structure offers not only a physical capture but also a chemical bonding of hydrogen bonding between cellulose and poly (acrylic acid) (PAA) binder. Si-bare and Si–CNF1wt appear distinct active materials detachment after 30 cycles. In contrast, Si–CNF2wt demonstrates 3386mAh/g in the initial cycle and remains 640mAh/g after 100 cycles without active materials detachment. The SEM images show that CNFs prevent cracking on silicon after cycling, indicating that Si/CNF 3D-net composite from the industrial and agricultural recycled wastes is a promising structure and green manufacturing for next-generation lithium-ion batteries. • Waste silicon from photovoltaic industry and waste rice straw from agriculture are recycled. • 3D-net structure of Si/CNF composite is fabricated by freeze-drying process. • 3D-net structure offers hydrogen bond formation and plays a physical capture with PAA binder. • CNFs effectively reduce the crack formation after cycling. • Si–CNF2wt/graphite composite demonstrates high retention about 90% after 100 cycles.