Ma Haiqiang, Yin Bo, Ye Tong, Egun Ishioma Laurene, Li Yafei, Zhang Xianglan, He Haiyong
School of Chemical and Environmental Engineering, China University of Mining & Technology (Beijing), Beijing 100083, China; Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences, Ningbo 315201, China.
J Colloid Interface Sci. 2025 Sep 16;702(Pt 2):139042. doi: 10.1016/j.jcis.2025.139042.
Hard carbon rich in closed pores is considered a highly promising anode candidate for advanced sodium-ion batteries (SIBs). Nevertheless, the precise regulation of closed pore structures is significantly impeded by the structural complexity of hard carbon. In this study, a hard carbon with tunable closed-pore architecture was constructed by using ZIF-8-derived porous carbon with uniform pore size (∼0.8 nm) and adjustable pore structure as the substrate. Carbonization temperature control and a chemical vapor deposition (CVD)-based pore-sealing strategy were combined to tailor the pore structure and optimize sodium storage performance. The results revealed that the size and number of closed pores are determined by the open-pore characteristics of the carbon substrate; specifically, substrates with larger micropores and higher specific surface areas promote the development of a greater number of closed pores of larger diameters. Benefiting from the optimized closed-pore architecture, the sample ZCHC-1200 exhibits outstanding electrochemical performance, delivering a high reversible capacity of 436.9 mAh g at 30 mA g with a plateau capacity of 265.0 mAh g, and retaining 86.5 % of its initial reversible capacity after 100 cycles. Even at a high current density of 2C, it provides 236.8 mAh g. In situ Raman and ex situ X-ray photoelectron spectroscopy (XPS) analyses revealed that the predominant contributor to the elevated plateau capacity is Na filling within closed pores. This study offers a novel strategy for designing closed pores through open-pore modulation, shedding light on the development of next-generation hard carbon anodes for SIBs.
富含封闭孔的硬碳被认为是先进钠离子电池（SIBs）极具前景的负极候选材料。然而，硬碳结构的复杂性严重阻碍了对封闭孔结构的精确调控。在本研究中，以具有均匀孔径（约0.8纳米）和可调节孔结构的ZIF-8衍生多孔碳为基底，构建了一种具有可调封闭孔结构的硬碳。结合碳化温度控制和基于化学气相沉积（CVD）的孔封闭策略来调整孔结构并优化储钠性能。结果表明，封闭孔的尺寸和数量由碳基底的开孔特性决定；具体而言，具有较大微孔和较高比表面积的基底会促进更多更大直径封闭孔的形成。受益于优化后的封闭孔结构，样品ZCHC-1200表现出优异的电化学性能，在30 mA g下具有436.9 mAh g的高可逆容量，平台容量为265.0 mAh g，并且在100次循环后保留其初始可逆容量的86.5%。即使在2C的高电流密度下，它仍能提供236.8 mAh g。原位拉曼光谱和非原位X射线光电子能谱（XPS）分析表明，平台容量升高的主要原因是封闭孔内的钠填充。本研究为通过开孔调制设计封闭孔提供了一种新策略，为下一代SIBs硬碳负极的开发提供了思路。
