Biomimetic Structural Foil Anode with Toughened Fracture Mechanism for High Energy Density Lithium-Ion Batteries

Mechanical fracture is a critical failure mode in lithium-ion batteries (LIBs), with crack propagation—central to the fracture mechanism—posing significant challenging in control. This issue is particularly pronounced in alloy-type anodes, which exhibit limited stress tolerance, constraining advancements toward higher energy densities in LIBs. Herein, we introduce a biomimetic laminated structure alloy-type foil anode by compositing Sn foil with single-walled carbon nanotubes that enables cyclic stability and high energy density. By modulating the crack propagation mechanism at multiple length scales, the biomimetic structure effectively raises the energy release threshold and facilitates the delocalization of electrochemically induced stress concentration, significantly delaying the onset of mechanical fracture during cycling. Consequently, the full-cell paired with LiFePO₄ and LiNi_0.8Co_0.1Mn_0.1O₂ cathodes achieve stable hundreds of cycles at practically relevant areal capacities. In particular, the full-cell with LiNi_0.8Co_0.1Mn_0.1O₂ at high loading of 10 mAh cm⁻² delivers a volumetric energy density of 1127.2 Wh L⁻¹, offering a promising pathway for advancing alloy-type foil anodes in high-energy LIBs.