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    用于快速高容量储钠的拓扑缺陷层状多孔炭

    Topologically Defective Lamellar Porous Carbon for Fast and High-Capacity Sodium-Ion Storage

    • 摘要: 以交联自组装层状嵌段共聚物为前驱体,通过低温掺杂-高温脱除杂原子策略制备了一类拓扑缺陷层状多孔炭(TDLPC)。通过扫描电子显微镜、拉曼光谱仪、顺磁共振波谱仪、透射电子显微镜、小角X射线散射仪和比表面与孔隙度分析仪等研究了TDLPC的层状形貌、缺陷结构、闭孔结构和开放孔结构。结果表明:杂原子脱除可以引发周边碳原子重排,TDLPC具有丰富的拓扑缺陷以及闭孔结构;原位形成的氧化硅模板在刻蚀后赋予TDLPC适量的开放微/介孔;TDLPC作为钠离子电池负极材料兼具高斜坡容量(130 mA·h/g)和高平台容量(83 mA·h/g),并且表现出优异的倍率性能(5 A/g下比容量为162 mA·h/g)以及长循环稳定性(1 A/g下循环500圈容量保持率高达94%)。

       

      Abstract: A class of topologically defective lamellar porous carbon (TDLPC) is fabricated by a thermal-driven heteroatom removal strategy using crosslinked self-assembled lamellar block copolymers as precursors. The structures (lamellar morphologies, defects, closed pores, and open pores) of TDLPC are investigated using methods such as scanning electron microscopy (SEM), Raman spectroscopy, electron paramagnetic resonance (EPR) spectroscopy, transmission electron microscopy (TEM), small-angle X-ray scattering (SAXS) spectroscopy, and specific surface area and porosity analyzer. Results demonstrate that the removal of heteroatoms induces the rearrangement of adjacent carbon atoms, leading to formation of abundant topological defects as well as closed pores, while etching of in situ formed silica templates generates moderate open micro/mesopores. Specifically, defect sites with enhanced sodium adsorption can raise sloping capacity, closed pores with suitable sites for sodium filling can increase plateau capacity, and open pores with interconnected channels can facilitate ion transfer. Benefiting from the above structural advantages, when TDLPC is used as anodes for sodium-ion batteries, it can simultaneously exhibit high sloping capacity (130 mA·h/g) as well as high plateau capacity (83 mA·h/g), excellent rate performance (162 mA·h/g at 5 A/g), and long cycling stability (capacity retention of 94% after 500 cycles at 1 A/g).

       

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