Double-shelled microscale porous Si anodes for stable lithium-ion batteries.

The critical challenge of high-capacity Si anodes lies in its volume changes, which breaks the electronic network and induces unstable solid electrolyte interphase (SEI). Herein, take microscale porous Si (PS) for an example, hierarchical Al 2 O 3 /multilayer graphene (mG) shells are fabricated to address the above problems. The inner ceramic Al 2 O 3 (1 nm) shell can uniform the volume expansion and confine the PS to the void space. In addition, the outer cross-linked mG not only provides sufficient electronic pathways but also helps to form a uniform and condense SEI. The synergetic advantages of the enhanced mechanical integrity, the robust electronic network, and the stable SEI; enable the electrodes exhibit remarkable cycling stability, a 92% capacity retention of 1716 mAh g−1 at 0.2 A g−1 over 90 cycles and 966 mAh g−1 at 1 A g−1 after 600 cycles. This work provides new insights in addressing the electrode materials with large volume expansions. • Micrometer-sized porous Si particles synthesized by scalable Cu-assisted etching. • Atomic coated Al 2 O 3 catalyst enabling multilayer graphene growth. • Double shells are demonstrated to uniform the volume change. • Achieving stable solid electrolyte interphase by multilayer graphene. [ABSTRACT FROM AUTHOR]