Multilayer Silicon Anode Structure for Fast-Charging Li Batteries

The negative electrode active material layer is divided into three distinct active material layers stacked in sequence on the current collector. The second active material layer contains silicon-containing particles with higher conductive material content, while the first and third layers have lower conductive material content. This segmentation allows different regions to contribute differently to capacity and conductivity, achieving high energy density without excessive overall complexity.

The conductive material is distributed non-uniformly across the three active material layers, with the second layer (containing silicon particles) having the highest conductive material content. This local quality enhancement ensures that the region with highest capacity demand receives disproportionate conductive support, optimizing both energy density and charging/discharging rate while maintaining manageable structural complexity.

The second active material layer containing silicon-containing particles is equipped with the highest conductive material content among the three layers. This localized enhancement of conductivity in the high-capacity region ensures that silicon particles contribute maximally to capacity while maintaining sufficient electron transport pathways, resolving the trade-off between capacity and conductivity.

The negative electrode employs a composite structure combining carbon-based active materials with silicon-containing particles across three layers. The conductive material (such as carbon black or graphite) is integrated throughout, with enhanced concentration in the silicon-containing layer, creating a composite system that leverages the high capacity of silicon while maintaining conductivity through the carbon matrix.

Rather than uniform distribution, the conductive material is strategically concentrated in the second active material layer containing silicon particles. This non-uniform local quality approach enhances charging/discharging rate by ensuring optimal conductivity where capacity demand is highest, while the layer-by-layer manufacturing process keeps production complexity manageable.

The conductive material distribution is segmented across three layers, with the second layer receiving the highest concentration. This segmentation allows targeted optimization of charging/discharging performance in the high-capacity silicon-containing region without requiring complex overall distribution control, as each layer can be processed separately during manufacturing.