Silicon Negative Electrode with Conductive Carbon Layer

The Si-based active material particles are embedded within a porous carbon matrix structure, creating a nested configuration where the carbon matrix surrounds and contains the Si particles. This nested structure allows the Si particles to expand and contract during charge-discharge cycles while being constrained by the carbon matrix, preventing volume expansion issues and maintaining battery life characteristics while preserving high theoretical capacity.

The negative electrode is constructed as a composite material system combining Si-based active material with porous carbon matrix and conductive carbon material. This composite structure integrates the high capacity advantage of Si with the structural stability and conductivity of carbon materials, resolving the contradiction between high theoretical capacity and battery life by synergistically combining different materials with complementary properties.

The conductive carbon material serves multiple functions simultaneously: it acts as part of the active material layer, provides conductivity enhancement, improves adhesive strength between layers, and reduces interfacial resistance. By merging these multiple functions into a single material component, the structure achieves improved reliability without proportionally increasing device complexity.

The conductive carbon material exhibits multi-functionality by simultaneously providing electrical conductivity, mechanical adhesion, and electrochemical activity. This universal material performs multiple roles that would otherwise require separate components, thereby improving adhesive strength and resistance properties while minimizing the increase in device complexity.