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_x/C@C) consisting of a disproportionated microsized SiO inner core, a homogeneous composite SiO_x/C interlayer (x ≈ 1.5), and a highly graphitized carbon outer layer. The robust SiO_x/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_x/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_0.8Co_0.15Al_0.05O₂ 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.

中文翻译：

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梯度复合结构为高性能锂离子电池提供稳定的微型低氧化硅基阳极

剧烈的体积变化和快速的容量衰减阻碍了微型阳极的实际应用。在此，我们提出了一种梯度复合策略，并制造了一种低氧化硅基复合阳极（d-SiO@SiO _x /C@C），该阳极由歧化微米级SiO内核、均质复合SiO _x /C中间层（x ≈ 1.5）组成。 ），以及高度石墨化的碳外层。坚固的SiO _x /C中间层可以实现应力的梯度消除，并通过共价键同时连接SiO内核和碳外层。结果，d-SiO@SiO _x /C@C在1 A/g下循环300次后，比容量为1023 mAh/g，保留率>90%，平均库仑效率>99.7%。与LiNi _0.8 Co _0.15 Al _0.05 O ₂阴极组装的全电池显示出基于总活性材料的569 Wh/kg的显着比能量密度以及优异的循环稳定性。我们的策略为设计结构和电化学稳定的高容量微型阳极提供了一种有前途的替代方案。