Abstract Flexible energy devices with high energy density and long cycle life are considered to be promising applications in portable electronics. In this study, silicon/carbon nanofiber (Si@CNF) core–shell electrode has been prepared by the coaxial electrospinning method. The precursors of polyimide (PI) were for the first time used to form the core–shell structure of Si@CNF, which depicts outstanding flexibility and mechanical strength. The effect of doping concentrations of silicon (Si) nanoparticles embedded in the fiber is investigated as a binder-free anode for lithium-ion batteries. A 15 wt% doped composite electrode demonstrates superior performance, with an initial reversible capacity of 621 mA h g−1 at the current density of 100 mA g−1 and a high capacity retention up to 200 cycles. The excellent cycling performance is mainly due to the carbonized PI core–shell structure, which not only can compensate for the insulation property of Si but also has the ability to buffer the volume expansion during the repeated charge–discharge process.

中文翻译：

---

将硅合理合成为聚酰亚胺衍生的中空电纺碳纳米纤维以增强锂存储

摘要 具有高能量密度和长循环寿命的柔性能源器件被认为在便携式电子产品中具有广阔的应用前景。本研究采用同轴静电纺丝法制备了硅/碳纳米纤维（Si@CNF）核壳电极。聚酰亚胺 (PI) 的前体首次用于形成 Si@CNF 的核壳结构，具有出色的柔韧性和机械强度。研究了嵌入纤维中的硅 (Si) 纳米粒子的掺杂浓度作为锂离子电池的无粘合剂阳极的影响。15 wt% 掺杂的复合电极表现出优异的性能，在 100 mA g-1 的电流密度下具有 621 mA h g-1 的初始可逆容量和高达 200 次循环的高容量保持率。