Silicon Negative Electrode with Side-Bonded CNTs for Volume Change

The patent uses a composite conductive agent consisting of both single-walled carbon nanotubes and carbon black. The carbon black acts as a buffer that absorbs mechanical stress during silicon expansion and contraction, protecting the carbon nanotube network from breakage while maintaining conductivity. This composite approach allows the system to benefit from the high conductivity of carbon nanotubes while mitigating their fragility through the presence of more resilient carbon black particles.

The patent modifies the conductive agent composition by introducing carbon black alongside carbon nanotubes. This parameter change in the conductive agent system allows it to accommodate the volume changes of silicon-based active material. The carbon black particles fill spaces and provide a compliant matrix that absorbs expansion stress, enabling the silicon to undergo volume changes without breaking the conductive network.

The patent employs a composite conductive agent system combining carbon nanotubes and carbon black, which enhances battery capacity while managing the increased complexity of dispersion preparation. The synergistic combination allows for improved conductivity and capacity that outweighs the additional manufacturing steps required to create and disperse the composite conductive agent mixture.