Scholarlink

<p>Freestanding electrodes promise higher energy densities and high-rate capabilities by eliminating inactive mass, but they require an interphase that preserves porosity and percolating electronic pathways during cycling. This paper reports a carbon nanofiber (CNF)-supported Si freestanding anode formed by programming the surface chemistry of electrospun polyacrylonitrile (PAN) to guide SiCl<sub>4</sub> interfacial hydrolysis–condensation, followed by stabilization/carbonization. KOH pretreatment and annealing generate oxygen- and nitrogen-containing groups that nucleate a uniform Si–O precursor; subsequent carbonization anchors a Si-containing oxide-rich interphase (hereinafter denoted as Si/SiO<sub>x</sub>, 40–50&#xa0;nm shell) to the CNF core via Si–O–C bonds. Microscopic and spectroscopic analyses confirmed a conformal carbon-core/Si–SiO<sub>x</sub> shell without over-coating or aggregation, maintaining junctions and fiber spacing. The freestanding electrodes delivered 727 and 288 mAh&#xa0;g<sup>−1</sup> at 0.1 and 10&#xa0;A&#xa0;g<sup>−1</sup>, respectively, retaining 85.9% capacity at 0.2&#xa0;A&#xa0;g<sup>−1</sup> and 79.8% at 1&#xa0;A&#xa0;g<sup>−1</sup>, and reduced charge-transfer resistance (approximately 130 → 44&#xa0;Ω) while increasing pseudocapacitive contribution and Li<sup>+</sup> diffusivity relative to control electrodes. In LiNi<sub>0.6</sub>Co<sub>0.2</sub>Mn<sub>0.2</sub>O<sub>2</sub> (NCM622)//CNF-supported Si full cells, the full cell delivered 176.5&#xa0;mAh&#xa0;g<sup>−1</sup> and retained 91.6% capacity after 300 cycles (approximately 0.028% capacity fade per cycle), demonstrating high-rate cyclability. To the best of our knowledge, this is the first CNF-supported Si freestanding anode that forms a conformal Si/SiO<sub>x</sub> interphase via PAN surface-functionalization-enabled SiCl<sub>4</sub> interfacial hydrolysis–condensation and stabilization/carbonization. The oxide-rich interphase, tethered to the CNF framework, preserves porosity and junctions, buffers Si volume change, stabilizes the solid electrolyte interphase (SEI), and sustains fast ionic/electronic transport, thereby enabling high-rate long-life Li-ion battery operation.</p> Graphical Abstract <p></p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

CNF-Supported Si Freestanding Anode with a Conformal Granular Si/SiOx Interphase for High-Rate, Long-Life Li-Ion Batteries

  • 期刊论文

  • 发表日期：

    2026年4月6日

查看全文
  • Hyeon-Woo Yang,
  • Perumal Naveenkumar,
  • Munisamy Maniyazagan,
  • Nayoung Kang,
  • K. P. Nithyanandam,
  • Woo Seung Kang,
  • Sun-Jae Kim

摘要

Freestanding electrodes promise higher energy densities and high-rate capabilities by eliminating inactive mass, but they require an interphase that preserves porosity and percolating electronic pathways during cycling. This paper reports a carbon nanofiber (CNF)-supported Si freestanding anode formed by programming the surface chemistry of electrospun polyacrylonitrile (PAN) to guide SiCl4 interfacial hydrolysis–condensation, followed by stabilization/carbonization. KOH pretreatment and annealing generate oxygen- and nitrogen-containing groups that nucleate a uniform Si–O precursor; subsequent carbonization anchors a Si-containing oxide-rich interphase (hereinafter denoted as Si/SiOx, 40–50 nm shell) to the CNF core via Si–O–C bonds. Microscopic and spectroscopic analyses confirmed a conformal carbon-core/Si–SiOx shell without over-coating or aggregation, maintaining junctions and fiber spacing. The freestanding electrodes delivered 727 and 288 mAh g−1 at 0.1 and 10 A g−1, respectively, retaining 85.9% capacity at 0.2 A g−1 and 79.8% at 1 A g−1, and reduced charge-transfer resistance (approximately 130 → 44 Ω) while increasing pseudocapacitive contribution and Li+ diffusivity relative to control electrodes. In LiNi0.6Co0.2Mn0.2O2 (NCM622)//CNF-supported Si full cells, the full cell delivered 176.5 mAh g−1 and retained 91.6% capacity after 300 cycles (approximately 0.028% capacity fade per cycle), demonstrating high-rate cyclability. To the best of our knowledge, this is the first CNF-supported Si freestanding anode that forms a conformal Si/SiOx interphase via PAN surface-functionalization-enabled SiCl4 interfacial hydrolysis–condensation and stabilization/carbonization. The oxide-rich interphase, tethered to the CNF framework, preserves porosity and junctions, buffers Si volume change, stabilizes the solid electrolyte interphase (SEI), and sustains fast ionic/electronic transport, thereby enabling high-rate long-life Li-ion battery operation.

Graphical Abstract