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Nano Research

Article Title

Rational structure design to realize high-performance SiOx@C anode material for lithium ion batteries

Keywords

mesoporous structure, silicon suboxide, electrochemical properties, anode, lithium ion batteries

Abstract

Silicon suboxide (SiOx) is considered to be one of the most promising materials for next-generation anode due to its high energy density. For its preparation, the wet-chemistry method is a cost-effective and readily scalable route, while the so-derived SiOx usually shows lower capacity compared with that prepared by high temperature-vacuum evaporation route. Herein, we present an elaborate particle structure design to realize the wet-chemistry preparation of a high-performance SiOx/C nanocomposite. Dandelionlike highly porous SiOx particle coated with conformal carbon layer is designed and prepared. The highly-porous SiOx skeleton provides plenty specific surface for intimate contact with carbon layer to allow a deep reduction of SiOx to a low O/Si ratio at relatively low temperature (700 °C), enabling a high specific capacity. The abundant mesoscale voids effectively accommodate the volume variation of SiOx skeleton, ensuring the high structural stability of SiOx@C during lithiation/delithiation process. Meanwhile, the three-dimensional (3D) conformal carbon layer provides a fast electron/ion transportation, allowing an enhanced electrode reaction kinetics. Owing to the optimized O/Si ratio and well-engineered structure, the prepared SiOx@C electrode delivers an ultra-high capacity (1,115.8 mAh·g−1 at 0.1 A·g−1 after 200 cycles) and ultra-long lifespan (635 mAh·g−1 at 2 A·g−1 after 1,000 cycles). To the best of our knowledge, the achieved combination of ultra-high specific capacity and ultra-long cycling life is unprecedented.

Graphical Abstract

Publisher

Tsinghua University Press

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