Negative-Electrode Enhancement Film for Dendrite and SEI Control

The patent applies preliminary action by pre-forming an inactive metal layer (such as aluminum, magnesium, or calcium) on the metal negative electrode surface before battery operation. This inactive layer serves as a sacrificial component that forms SEI film in advance, preventing direct contact between the electrolyte and the active metal negative electrode. By performing the SEI formation action beforehand on an inactive material, the patent reduces continuous electrolyte consumption during battery cycling while maintaining the benefits of increased specific surface area from three-dimensional current collectors.

The patent employs composite materials by combining an active metal negative electrode (such as lithium, sodium, or potassium) with an inactive metal layer (such as aluminum, magnesium, or calcium). This composite structure allows the active metal to provide high capacity and energy density while the inactive metal layer provides a stable surface that reduces current density and prevents dendrite formation. The inactive metal layer acts as an intermediate layer that maintains the benefits of high-capacity metal electrodes while mitigating their inherent safety issues.

The patent applies the flexible shells and thin films principle by using an inactive metal layer as a flexible protective interface between the silicon-based negative electrode material and the electrolyte. This thin film layer accommodates the volume expansion of silicon during lithium intercalation without causing structural failure, preventing electrode material peeling and powdering. The inactive metal layer acts as a buffer that maintains structural integrity during the dramatic volume changes that occur when silicon expands over 300% during charging.