Silicon Negative Electrode Structure for Conductive Cycle Stability

The patent employs a flexible polymer binder (polyacrylic acid or carboxymethyl cellulose) that can accommodate the expansion and contraction of silicon-containing materials during charging and discharging cycles. This flexible binder maintains electrode structure stability while allowing the silicon material to undergo volume changes, thus resolving the contradiction between high capacity and structural stability.

The patent creates a composite negative electrode structure combining silicon-containing particles with carbon materials and polymer binders. This composite approach allows the silicon to provide high capacity while the carbon matrix and flexible binder maintain structural integrity during cycling, preventing electrode degradation.

The patent optimizes the binder content to a specific range (1-5 wt% relative to silicon-containing material) to achieve the best balance between mechanical strength and electrical conductivity. Additionally, the binder is crosslinked through heating treatment to enhance strength while minimizing conductivity loss, demonstrating parameter optimization to resolve the contradiction.

The patent applies binder and conductive material in specific proportions and distributions within the electrode structure. By locally optimizing the composition around silicon particles with conductive carbon materials and appropriate binder amounts, the electrode achieves both mechanical integrity and electrical conductivity without uniform increases in binder content.