Significant efforts continue to be directed toward the construction of anode materials with high specific capacity and long cycling stability for lithium-ion batteries (LIBs). In this context, silicon is preferred due to its high capacity even though it has a problem of excessive volume expansion during electrochemical reactions as well as poor cyclability due to a reduction in conductivity. Hence, the hybridization of silicon with suitable materials could be a promising approach to overcome the abovementioned problems. Herein, we demonstrate the uniform decoration of nickel oxide (NiO) nanoparticles (15–20 nm) on silicon nanosheets using bis(cyclopentadienyl) nickel(II) (C₁₀H₁₀Ni) at low temperatures, taking advantage of the presence of two unpaired electrons in an antibonding orbital in the cyclopentadienyl group. The formation and growth mechanism are discussed in detail. The electrochemical study of the nanocomposite revealed an initial delithiation capacity of 2507 mA h g⁻¹ with a reversible capacity of 2162 mA h g⁻¹, having 86% retention and better cycling stability for up to 500 cycles. At the optimum concentration, NiO nanoparticles facilitate Li⁺-ion adsorption, which in turn accelerates the transport of Li⁺-ions to active sites of silicon. The Warburg coefficient and Li⁺-ion diffusion at the electrodes confirm the enhancement in the charge transfer process at the electrode/electrolyte interface with NiO nanoparticles. Further, the NiO nanoparticles with uniform distribution suppress the agglomeration of Si nanosheets and provide sufficient space to accommodate a volume change in Si during cycling, which also reduces the diffusion path length of the Li-ions. It also helps to strengthen the mechanical stability, which might be helpful in preventing the cracking of silicon due to volume expansion and maintains the Li-ion transport pathway of the active material, resulting in enhanced cycling stability. Due to the synergic effect between NiO nanoparticles and Si sheets, the nanocomposite delivers high reversible capacity.

中文翻译：

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氧化镍纳米粒子在硅上的装饰对增强锂离子电池电化学性能的协同作用

继续致力于构建具有高比容量和长循环稳定性的锂离子电池（LIB）负极材料。在这种情况下，硅由于其高容量而被优选，尽管它在电化学反应过程中具有过度的体积膨胀以及由于电导率降低而导致循环性能差的问题。因此，硅与合适材料的杂化可能是克服上述问题的有希望的方法。在此，我们展示了使用双（环戊二烯基）镍（ II）（C ₁₀ H ₁₀）在硅纳米片上均匀修饰氧化镍（NiO）纳米颗粒（15-20 nm）Ni）在低温下，利用环戊二烯基的反键轨道中存在两个不成对电子。详细讨论了其形成和生长机制。纳米复合材料的电化学研究表明，初始脱锂容量为 2507 mA hg ^-1，可逆容量为 2162 mA hg ^-1，具有 86% 的保留率和更好的循环稳定性，最多可循环 500 次。在最佳浓度下，NiO 纳米颗粒促进了 Li ⁺离子的吸附，进而加速了Li ⁺离子向硅活性位点的传输。Warburg 系数和 Li ⁺电极处的离子扩散证实了在电极/电解质界面与 NiO 纳米颗粒的电荷转移过程的增强。此外，均匀分布的 NiO 纳米颗粒抑制了 Si 纳米片的团聚，并提供了足够的空间来适应循环过程中 Si 的体积变化，这也减少了锂离子的扩散路径长度。它还有助于增强机械稳定性，这可能有助于防止硅因体积膨胀而开裂，并维持活性材料的锂离子传输路径，从而提高循环稳定性。由于 NiO 纳米颗粒和 Si 片之间的协同作用，纳米复合材料具有高可逆容量。