Liang Yucang, Oettinger Jonathan David, Zhang Peng, Xu Bin
Institut für Anorganische Chemie, Eberhard Karls Universität Tübingen, Auf der Morgenstelle 18, 72076 Tübingen, Germany.
State Key Laboratory of Organic-Inorganic Composites, Beijing Key Laboratory of Electrochemical Process and Technology for Materials, Beijing University of Chemical Technology, Beijing 100029, P. R. China.
Nanoscale. 2020 Jul 23;12(28):15157-15168. doi: 10.1039/d0nr03019h.
In this paper, phase-pure monodisperse NiO nanocrystals were prepared in a temperature-dependent manner via a thermal decomposition approach, showing sphere-like shapes and snowflake-like NiO arrays. Such hydrophobic NiO nanocrystals were converted into hydrophilic nickel oxide-sodium oleate-Pluronic P123 (NiO-SO-P123) micelles in aqueous solution. Phenolic resin (PR) formed in situ was successfully deposited on the hydrophilic area of the NiO-SO-P123 micelles via a heterogeneous nucleation mechanism to form NiO-phenolic resin nanospheres (NiO-PRNSs) with uniform particle size. By adjusting the size and amount of NiO nanocrystals used, the diameter of the obtained NiO-PRNSs can be effectively controlled from 185 to 103 nm, and a narrow size distribution is seen, revealing the effects of the NiO nanocrystals on the reconstructed NiO-integrated micellar size. Meanwhile, the morphology (ring buoy, semi-bowl, sphere) depends upon the initial amount of NiO. The carbonization of NiO-PRNSs produced Ni(0)-integrated hollow N-doped carbon nanospheres (Ni(0)-HNCNSs), which involved the conversion of NiO to Ni(0) and the contraction of particle size, and the size and distribution was affected by the starting amount of NiO. However, upon using monodisperse and polyhedral FeO nanocrystals, the obtained FeO-free/-incompletely-filled/-fully-filled core-shell structured Fe-PRNSs showed relatively uniform particle size, except for when multiple FeO cores formed large FeO-PR nanospheres after starting with the same initial FeO size. The carbonized FeO-HNCNSs still preserved a pomegranate-like core-shell structure with uniform size and there was no change in the size of the FeO nanocrystals. Moreover, high-loaded Ni(0)-integrated hollow or solid N-doped carbon microspheres or flakes can be synthesized via a one-pot method, but with a broad size range, showing highly uniform Ni distribution with a Ni size as small as 8.5 nm. Note that Ni(0)- and FeO-HNCNSs were prepared for the first time according to our knowledge. Finally, low-loaded Ni- and FeO-HNCNSs with uniform morphology and size were chosen as representatives to investigate their electrochemical properties for lithium-ion batteries (LIBs), showing excellent lithium storage properties and superior reversibility. This study provides a potential strategy for controlling the sizes and morphologies of metal-integrated carbon materials to obtain adjustable electrochemical properties.
在本文中，通过热分解法以温度依赖的方式制备了相纯的单分散NiO纳米晶体，其呈现出球状形状和雪花状NiO阵列。这种疏水性NiO纳米晶体在水溶液中转化为亲水性氧化镍-油酸钠-普朗尼克P123（NiO-SO-P123）胶束。原位形成的酚醛树脂（PR）通过异质成核机制成功沉积在NiO-SO-P123胶束的亲水区，形成粒径均匀的NiO-酚醛树脂纳米球（NiO-PRNSs）。通过调整所用NiO纳米晶体的尺寸和数量，可将所得NiO-PRNSs的直径有效控制在185至103nm之间，且粒径分布较窄，这揭示了NiO纳米晶体对重构的含NiO胶束尺寸的影响。同时，其形态（环形浮标、半球形、球形）取决于NiO的初始量。NiO-PRNSs的碳化产生了含有Ni(0)的中空N掺杂碳纳米球（Ni(0)-HNCNSs），这涉及到NiO向Ni(0)的转化以及粒径的收缩，且尺寸和分布受NiO起始量的影响。然而，使用单分散的多面体FeO纳米晶体时，除了在相同初始FeO尺寸下多个FeO核形成大的FeO-PR纳米球的情况外，所得不含FeO/部分填充FeO/完全填充FeO的核壳结构Fe-PRNSs显示出相对均匀的粒径。碳化后的FeO-HNCNSs仍保留石榴状核壳结构，尺寸均匀，且FeO纳米晶体的尺寸没有变化。此外，通过一锅法可合成高负载的含有Ni(0)的中空或实心N掺杂碳微球或薄片，但尺寸范围较宽，显示出高度均匀的Ni分布，Ni尺寸小至8.5nm。请注意，据我们所知，Ni(0)-和FeO-HNCNSs是首次制备。最后，选择形态和尺寸均匀的低负载Ni-和FeO-HNCNSs作为代表，研究它们在锂离子电池（LIBs）中的电化学性能，结果显示出优异的储锂性能和卓越的可逆性。本研究为控制金属集成碳材料的尺寸和形态以获得可调的电化学性能提供了一种潜在策略。
