Hierarchical Yolk‐Shell Silicon/Carbon Anode Materials Enhanced by Vertical Graphene Sheets for Commercial Lithium‐Ion Battery Applications

Abstract

Yolk‐shell structured silicon/carbon (YS‐Si/C) anode materials show promise for commercial lithium‐ion batteries (LIBs) because of their high specific capacity and excellent cycling life. However, their commercialization has not been realized despite nearly a decade of research, primarily due to poor mechanical strength, limited rate capability, and low energy density. This study reports a hierarchical YS‐Si/C anode material synthesized via thermal chemical vapor deposition for the growth of vertical graphene sheets (VGSs), polymer self‐assembly, and one‐step carbonization, which establishes connections between the Si core and carbon shell through VGSs, enhancing the electrochemical and mechanical characteristics of the YS‐Si/C material. The unique material outperforms VGSs‐free composites, which presents a high specific capacity of 1683.2 mAh g−1 at 0.1 C, excellent rate performance of 552.2 mAh g−1 at 10 C, and superior capacity retention of 80.1% after 1000 cycles. When matched with LiNi0.8Co0.1Mn0.1O2 cathodes, the ampere‐hour‐level pouch cell delivers high gravimetric and volumetric energy densities of 429.2 Wh kg−1 and 1083 Wh L−1, respectively. Finite element analysis shows that VGSs reduce stress concentration on the carbon shell, helping hollow materials withstand industrial electrode calendaring. This work demonstrates potential for the commercial application of YS‐Si/C anode materials in practical LIBs.