Mechanistic insight into the role of N-doped carbon matrix in electrospun binder-free Si@C composite anode for lithium-ion batteries
Mechanistic insight into the role of N-doped carbon matrix in electrospun binder-free Si@C composite anode for lithium-ion batteries
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DOI：
10.1007/s11581-020-03484-x
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发表时间：
2020-02
期刊：
影响因子：
2.8
通讯作者：
Kaixiang Shen;Hedong Chen;Xianhua Hou;Shaofeng Wang;Haiqing Qin;Yumei Gao;Jiadong Shen
中科院分区：
文献类型：
--
作者：
Kaixiang Shen;Hedong Chen;Xianhua Hou;Shaofeng Wang;Haiqing Qin;Yumei Gao;Jiadong Shen
为了提高Si基阳极的长循环稳定性和倍率性能，我们采用低成本、简单的静电纺丝和低温热解工艺制备了一种核壳结构的Si@NC复合材料，并在其表面修饰了N掺杂的碳网络。在铜箔上纺制的Si@PVP/尿素织物复合材料直接干燥，然后切割成圆片用作电极板，而不需要额外的导电剂和粘合剂。特殊结构Si@NC的倍率性能和循环稳定性的提高主要归因于N掺杂的碳基体提供了大量的活性位点，这些活性位点有效地吸引了Li，并且核壳结构为Si@NC复合材料提供了高的机械强度。重要的是，在1.6和3.2 A g-1的高电流密度下观察到Si@NC的容量留存率几乎提高了3倍。同时，DFT计算证实，在N掺杂的碳模型中，Li更容易被N活性位吸附，增强化学吸附能力，从而有更多的机会在短时间内捕获快速移动的Li.这对后续研究具有重要的理论指导意义。研究结果为锂离子电池的大规模生产和应用提供了可能性。
To improve the long cyclic stability and rate capability of Si-based anode, we demonstrate a core-shell structural Si@NC composite decorates with N-doped carbon network using a low-cost, a simple process of electrospinning and low-temperature pyrolysis. Si@PVP/Urea fabric composite spun on the copper foil was directly carbonized and then was cut into wafers used as the electrode plates without extra conductive agent and binder. The enhanced rate capability and cyclic stability of special structural Si@NC is mainly ascribable to N-doped carbon matrix providing numerous active sites, which attract Li to those points in an efficient way, and the core-shell structures supply high mechanical strength for Si@NC composite. Importantly, almost 3-fold improvement in the capacity retention rate of the Si@NC has been observed at high current densities of 1.6 and 3.2 A g−1. Meanwhile, DFT calculations confirm that Li will be easily adsorbed by N-active sites in N-doped carbon model to strengthen chemical absorption ability, which could have more chance to grab the quickly moving Li in a brief period. It is significant for theoretical guidance of subsequent studies. The findings should make an important contribution providing a great possibility for the mass production and application to the field of lithium-ion battery.