Zhao Yang, Yang Xiaofei, Kuo Liang-Yin, Kaghazchi Payam, Sun Qian, Liang Jianneng, Wang Biqiong, Lushington Andrew, Li Ruying, Zhang Huamin, Sun Xueliang
Department of Mechanical and Materials Engineering, University of Western Ontario, London, Ontario, N6A 5B9, Canada.
Division of Energy Storage, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Zhongshan Road 457, Dalian, 116023, China.
Small. 2018 May;14(20):e1703717. doi: 10.1002/smll.201703717. Epub 2018 Apr 15.
Na metal anode attracts increasing attention as a promising candidate for Na metal batteries (NMBs) due to the high specific capacity and low potential. However, similar to issues faced with the use of Li metal anode, crucial problems for metallic Na anode remain, including serious moss-like and dendritic Na growth, unstable solid electrolyte interphase formation, and large infinite volume changes. Here, the rational design of carbon paper (CP) with N-doped carbon nanotubes (NCNTs) as a 3D host to obtain Na@CP-NCNTs composites electrodes for NMBs is demonstrated. In this design, 3D carbon paper plays a role as a skeleton for Na metal anode while vertical N-doped carbon nanotubes can effectively decrease the contact angle between CP and liquid metal Na, which is termed as being "Na-philic." In addition, the cross-conductive network characteristic of CP and NCNTs can decrease the effective local current density, resulting in uniform Na nucleation. Therefore, the as-prepared Na@CP-NCNT exhibits stable electrochemical plating/stripping performance in symmetrical cells even when using a high capacity of 3 mAh cm at high current density. Furthermore, the 3D skeleton structure is observed to be intact following electrochemical cycling with minimum volume change and is dendrite-free in nature.
由于具有高比容量和低电位，钠金属阳极作为钠金属电池（NMBs）的一种有前景的候选材料，正吸引着越来越多的关注。然而，与锂金属阳极使用中面临的问题类似，金属钠阳极仍存在关键问题，包括严重的苔藓状和树枝状钠生长、不稳定的固体电解质界面形成以及巨大的无限体积变化。在此，展示了以氮掺杂碳纳米管（NCNTs）修饰的碳纸（CP）作为三维主体的合理设计，以获得用于NMBs的Na@CP-NCNTs复合电极。在这种设计中，三维碳纸充当钠金属阳极的骨架，而垂直排列的氮掺杂碳纳米管可以有效减小CP与液态金属钠之间的接触角，这被称为“亲钠性”。此外，CP和NCNTs的交叉导电网络特性可以降低有效局部电流密度，从而实现均匀的钠成核。因此，即使在高电流密度下使用3 mAh cm的高容量，所制备的Na@CP-NCNT在对称电池中仍表现出稳定的电化学镀/脱镀性能。此外，观察到三维骨架结构在电化学循环后保持完整，体积变化最小且本质上无枝晶。
