Nanofiber-in-microfiber carbon/silicon composite anode with high silicon content for lithium-ion batteries
Nanofiber-in-microfiber carbon/silicon composite anode with high silicon content for lithium-ion batteries
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DOI：
10.1016/j.carbon.2022.11.100
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发表时间：
2023-01
期刊：
影响因子：
10.9
通讯作者：
Yixian Pei;Yuxin Wang;An-Yi Chang;Yixin Liao;Shuangpeng Zhang;Xiufang Wen;Shengnian Wang
中科院分区：
文献类型：
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作者：
Yixian Pei;Yuxin Wang;An-Yi Chang;Yixin Liao;Shuangpeng Zhang;Xiufang Wen;Shengnian Wang
富硅阳极被期望利用锂离子电池（LIB）的能量容量朝向关键市场。我们使用同轴静电纺丝装置制备了具有纳米纤维中微纤维结构的新型富硅复合阳极。允许高硅含量的聚乙烯醇（PVA）溶液作为中心流，其将硅纳米颗粒保持为短的、分支的复合纳米纤维。这些纳米纤维被长的、可延展的微纤维包裹，微纤维由在鞘液中提供的聚丙烯腈（PAN）制成。在碳化之后，将所接收的碳/硅复合材料作为LIB的阳极进行测试，其中富硅纳米纤维承载大部分锂离子，而其源自PVA的薄碳皮促进导电性和电荷转移。外部PAN衍生的微纤维为那些包封的富硅纳米纤维提供所需的结构支撑，使最终的复合材料也成为集成的三维集流体。纳米纤维形态和其间的空隙空间有助于适应锂化/脱锂过程中臭名昭著的体积膨胀问题。新的复合材料被证实其纳米纤维在微纤维配置。这种独特的纤维状阳极材料的硅含量为40%，通过有效平衡与富硅阳极相关的一些主要挑战，从第50次循环到第250次循环，实现了900 mAh g− 1的比容量和90%的容量保持率。
Silicon-rich anodes are desired to leverage the energy capacity of lithium-ion batteries (LIBs) towards critical markets. We prepared new silicon-rich composite anodes with a nanofiber-in-microfiber architecture using a co-axial electrospinning setup. A polyvinyl alcohol (PVA) solution that allows high silicon content serves as the central stream, which holds silicon nanoparticles into short, branched composite nanofibers. These nanofibers were wrapped by long, ductile microfibers made of polyacrylonitrile (PAN) that is supplied in the sheath fluid. After carbonization, the received carbon/silicon composites were tested as the anode of LIBs, in which the silicon-rich nanofibers host the majority of lithium ions while their thin carbon skin originated from PVA promotes the conductivity and charge transfer. The outside PAN-derived microfibers provide needed structural support for those encapsulated silicon-rich nanofibers, making the final composites also an integrated, three-dimensional current collector. The nanofibrous morphology and the void space in between help accommodate the notorious volume expansion issues during lithiation/delithiation. The new composites were confirmed on their nanofiber-in-microfiber configuration. With a Si content of 40%, this unique fibrous anode material achieves ∼900 mAh g−1specific capacity and ∼90% capacity retention from cycle 50 to cycle 250 by effectively balancing some major challenges associated with silicon-rich anodes.