Constructing closed pore structures is essential for improving the plateau capacity of high-capacity hard carbon (HC) anodes for sodium-ion batteries. However, the absence of a straightforward and efficient strategy for constructing closed pores has hindered the advancement of high-capacity HC anodes. Here, we have developed a spatial confinement strategy for constructing closed pore structures using pyrolytic carbon (PC) as substrate and pyrolysis gas as the carbon source for chemical vapor deposition. The deposition of pyrolysis gas effectively tightens the pore entrance, thereby preventing electrolyte infiltration and transforming the open pores in the PC into highly efficient sites for sodium storage. The obtained optimal anodes demonstrate a remarkable specific capacity of 324.6 mAh g-1. More importantly, we calculate the kinetic diameters of the carbon source molecules from their iso-electron density surfaces and correlate them with the mechanism of closed pore formation, which will effectively guide the fabrication of closed pores for sodium storage.

中文翻译：

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受气态分子动力学直径调节钠储存的空间限制策略


构建封闭孔结构对于提高钠离子电池用高容量硬碳 （HC） 负极的平台容量至关重要。然而，缺乏构建封闭孔隙的简单有效的策略阻碍了高容量 HC 阳极的发展。在这里，我们开发了一种空间限制策略，用于使用热解碳 （PC） 作为基材，热解气体作为化学气相沉积的碳源来构建封闭孔结构。热解气体的沉积有效地收紧了孔隙入口，从而防止电解液渗入，并将 PC 中的开放孔转化为钠储存的高效场所。获得的最佳阳极显示出 324.6 mAh g-1 的显着比容量。更重要的是，我们从碳源分子的等电子密度表面计算碳源分子的动力学直径，并将其与闭孔形成的机制相关联，这将有效地指导用于钠储存的闭孔的制造。