Design Strategies toward High-Performance Hybrid Carbon Bilayer Anode for Improved Ion Transport and Reaction Stability

Compositing carbon-based materials with different properties can significantly improve the energy density of lithium-ion batteries for applications that require high power, such as electric vehicles, owing to their effective current distribution. Nevertheless, the chemical reaction is not uniform throughout the entire depth of conventionally blended electrodes. This study proposes a hybrid patterned bilayer anode that comprises a blended layer of spherical crystalline graphite (SCG) and soft carbon and a single layer of SCG alone, which maintains a stable ionic reaction at the electrode surface and improves ion transport. This bilayer anode has a smaller, more uniform solid electrolyte interphase layer that is more evenly distributed throughout the electrode compared with the blended electrode. The electrode pattern interfaces, which are optimized by controlling the pattern size, ensure excellent mechanical adhesion and low internal resistance. Consequently, the patterned bilayer half-cell achieves a high-capacity retention of 85.9% after 500 charge–discharge cycles at 1 C. The full cell also attains an energy density of 178.7 Wh kg⁻¹ with fast discharging at 10 C, which is 2.3 times higher than that of the single-layer SCG electrode.