A Gradient Composite Structure Enables a Stable Microsized Silicon Suboxide-Based Anode for a High-Performance Lithium-Ion Battery.

Liu, Zhenhui; Hu, Rui; Yu, Ruohan; Zheng, Mingbo; Zhang, Yulin; Chen, Xuanning; Shen, Laifa; Xia, Yongyao · Nano Lett · 2024

basic_science · Level V

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Abstract

The practical application of microsized anodes is hindered by severe volume changes and fast capacity fading. Herein, we propose a gradient composite strategy and fabricate a silicon suboxide-based composite anode (d-SiO@SiO<sub><i>x</i></sub>/C@C) consisting of a disproportionated microsized SiO inner core, a homogeneous composite SiO<sub><i>x</i></sub>/C interlayer (<i>x</i> ≈ 1.5), and a highly graphitized carbon outer layer. The robust SiO<sub><i>x</i></sub>/C interlayer can realize a gradient abatement of stress and simultaneously connect the inner SiO core and carbon outer layer through covalent bonds. As a result, d-SiO@SiO<sub><i>x</i></sub>/C@C delivers a specific capacity of 1023 mAh/g after 300 cycles at 1 A/g with a retention of >90% and an average Coulombic efficiency of >99.7%. A full cell assembled with a LiNi<sub>0.8</sub>Co<sub>0.15</sub>Al<sub>0.05</sub>O<sub>2</sub> cathode displays a remarkable specific energy density of 569 Wh/kg based on total active materials as well as excellent cycling stability. Our strategy provides a promising alternative for designing structurally and electrochemically stable microsized anodes with high capacity.