Carbon ( IF 10.5 ) Pub Date : 2021-10-22 , DOI: 10.1016/j.carbon.2021.10.062
Chuanlei Qi 1 , Shengping Li 1 , Zipan Yang 1 , Zhihua Xiao 1 , Lu Zhao 1 , Fan Yang 1 , Guoqing Ning 1 , Xinlong Ma 1 , Chengxiu Wang 1 , Jun Xu 2 , Jinsen Gao 1
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Silicon (Si) is capable of delivering a high theoretical specific capacity as anode in Li ion batteries (LIBs), but suffers from remarkable volume expansion, poor electrical conductivity and unstable solid electrolyte interface (SEI) film. Carbon coating is a facile and effective method to improve the electrochemical stability of Si anode. However, the electrode behavior performance of Si@C anode will be affected by the different thickness of carbon coating layer. Here, core-shell nanostructured Si@C materials with various thickness of carbon coating (around 2–30 layers) are prepared via the chemical vapor deposition with different deposition times. Especially, the Si@C composite with 2–3 carbon coating layers exhibits an outstanding electrical conductivity and strong mechanical strength, which is in favor of buffering the dramatic volume expansion of Si nanoparticles during the repeated lithiation/delithiation processes. As the anode material, the Si@C electrode exhibits a high capacity (3019 mA h g−1 at 0.2 A g−1), excellent rate capability (1647 mA h g−1 at 5 A g−1) and long-term cycling stability. Moreover, the excellent durability is also delivered by the full pouch-cell fabricated with Si@C anode and Ni0.6Co0.2Mn0.2O2 cathode. The huge volume expansion and unstable SEI film can be effectively alleviated by the suitable carbon coating layers.
中文翻译:
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合适的硅阳极碳涂层厚度
硅 (Si) 作为锂离子电池 (LIB) 中的负极能够提供高理论比容量,但存在显着的体积膨胀、导电性差和不稳定的固体电解质界面 (SEI) 膜。碳涂层是提高硅负极电化学稳定性的一种简便有效的方法。然而,不同厚度的碳涂层会影响Si@C负极的电极行为性能。在这里,通过不同沉积时间的化学气相沉积制备了具有不同碳涂层厚度(约 2-30 层)的核壳纳米结构 Si@C 材料。特别是具有 2-3 层碳涂层的 Si@C 复合材料表现出优异的导电性和强大的机械强度,这有利于在重复的锂化/脱锂过程中缓冲 Si 纳米颗粒的剧烈体积膨胀。作为负极材料,Si@C 电极表现出高容量(3019 mA hg-1 at 0.2 A g -1),优异的倍率性能(1647 mA hg -1 at 5 A g -1)和长期循环稳定性。此外,由 Si@C 阳极和 Ni 0.6 Co 0.2 Mn 0.2 O 2阴极制造的全软包电池也提供了出色的耐久性。合适的碳涂层可以有效缓解巨大的体积膨胀和不稳定的SEI膜。