High Loading Micro-Si anode with Oxidation Controlled Carbon Nanotube Scaffolds: Towards Pouch Cell Fabrication in Industrial Level

Silicon (Si) emerges as a promising anode material for lithium-ion batteries (LiB) due to its ultrahigh theoretical capacity and cost-effectiveness. However, the large-scale fabrication of high-loading Si anodes remains rarely documented. Herein, we developed large-scale oxidation-controlled carbon nanotube (CNT) scaffolds with high electrical conductivity by regulating oxidation conditions. The oxidation-controlled CNTs are self-assembled into an interwoven network, facilitating their incorporation with micro-Si particles and a polymer binder to form a stable aqueous slurry. We investigated the feasibility of scalable electrode coating through rheological analysis, revealing the viscoelastic slurry suitable for industrial-scale shear-coating. Utilizing the bar-coating method, we fabricated a large-scale electrode (30 cm x 40 cm) and confirmed the uniformity of the electrode layer via statistical quality control charts, demonstrating scalability for industrial production. In terms of electrochemical performance, the optimized Si anode surpassed previously reported Si-based anodes, exhibiting a high areal capacity of 3.9 mAh cm−2 and exceptional capacity retention (94 %) after 50 cycles. Finally, we validated the development of the Si anode, nearing industrial-level standards with exceptional pouch cell performance. The oxidation-controlled CNT scaffolds not only enable scalable coating of electrode materials but also effectively mitigate the expansion of micro-Si particles by uniformly covering the Si surface.