Search

Nanostructured transition metal oxide anodes have attracted considerable attention for high-performance lithium-ion batteries (LIBs). However, their low rate capability and rapid capacity decline resulting from their low electronic conductivities and inevitable substantial volumetric changes prevent them from being commercialized as anodes for LIBs. Herein, we design a high-performance anode for LIBs consisting of a yolk–shell structured Fe2O3@C nanoring (NR) composite that comprises a NR-like Fe2O3 core entirely protected by a fine porous carbon (C) shell to overcome such obstacles. This advantageous yolk–shell structural design can buffer the significant volume variations of Fe2O3 cores without damaging the microstructure of the electrode. Thanks to the unique structural features, the as-built electrode shows a remarkable electrochemical performance, namely, a large specific capacity of 846 mA h g−1 after 100 cycles at 0.2 A g−1, a superior rate performance of 688 mA h g−1 at 4 A g−1, and a remarkable cycling life (300 cycles, 945 mA h g−1 at 4.0 A g−1). Hence, this electrode is much better than a pure Fe2O3 NR electrode. [ABSTRACT FROM AUTHOR]

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]