Silicon-based materials (e.g., nanosilicon and porous silicon) are being actively researched for use as anodes in high-energy Li-ion batteries (LIBs), which have high specific capacities and long charging/discharging cycling lifespans. However, the enormous specific surface area of nanosilicon and porous silicon results in a high preparation cost, agglomeration, and a low initial coulombic efficiency (ICE), all of which hinder industrialization. Low-cost micron bulk silicon has an extremely huge volume change and a low conductivity during alloying/dealloying and therefore cannot be directly used as an anode. Here, we develop a novel sol-gel method that couples low-cost micron silicon (Si) to a uniformly Ni-doped carbon layer. The Ni-mediated polymerization of sodium alginate (SA) by coulombic self-assembly and produces ionic self-locking, and is followed by in situ freeze-drying and low-temperature carbonization to produce the desired composite, Si/Ni@C. Si/Ni@C exhibits a crack-free graphite carbon layer, which increases the Si ICE of 75.5% to 84.6% and reduces the impedance; this carbon layer also promotes long-cycle stability, resulting in a Si/Ni@C capacity of 516 mAhg⁻¹ after 100 cycles at 0.1 Ag⁻¹, which is higher than that of Si (84 mAhg⁻¹). This result is attributed to the increased cross-linking of SA by Ni-doping, which enhances the mechanical strength of the carbon layer and the conductivity and reduces side reactions and the volume change of Si during alloying/dealloying.

硅基材料（例如，纳米硅和多孔硅）正被积极研究用作高能量锂离子电池（LIB）的阳极，这些电池具有高比容量和长的充电/放电循环寿命。然而，纳米硅和多孔硅的巨大的比表面积导致高的制备成本，团聚和低的初始库伦效率（ICE），所有这些都阻碍了工业化。低成本的微米级块状硅在合金化/脱合金过程中具有巨大的体积变化和低电导率，因此不能直接用作阳极。在这里，我们开发了一种新颖的溶胶-凝胶方法，该方法将低成本的微米级硅（Si）耦合到均匀掺杂Ni的碳层上。镍通过库仑自组装介导的藻酸钠（SA）聚合反应，并产生离子自锁，然后进行原位冷冻干燥和低温碳化以生产所需的复合材料Si / Ni @ C。Si / Ni @ C表现出无裂纹的石墨碳层，可将Si ICE的75.5％提高到84.6％，并降低了阻抗；该碳层还提高了长期循环稳定性，导致Si / Ni @ C容量为516 mAhg在0.1 Ag ^-1下经过100次循环后的^-1，高于Si（84 mAhg ^-1）。该结果归因于镍掺杂增加了SA的交联，从而增强了碳层的机械强度和导电性，并减少了合金化/脱合金过程中的副反应和Si的体积变化。