School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, China.
School of Materials Science and Engineering, Xi'an University of Technology, Xi'an 710048, China.
J Colloid Interface Sci. 2023 Mar;633:723-736. doi: 10.1016/j.jcis.2022.11.131. Epub 2022 Dec 5.
The research on the structure of advanced electrode materials is significant in the field of supercapacitors. Herein, for the first time, we propose a novel 3D/3D composite structure by a multi-step process, in which 3D hollow NiCo LDH nanocages are immobilized on 3D sea urchin-like CoO microspheres. Results show that the 3D CoO acts as an efficient and stable channel for ion diffusion, while the hollow NiCo LDH provides abundant redox-active sites. The calculated results based on density function theory (DFT) show that the CoO@NiCo LDH heterostructure has an enhanced density of states (DOS) near the Fermi level and strong adsorption capacity for OH, indicating its excellent electrical conductivity and electrochemical reaction kinetics. As a result, the CoO@NiCo LDH electrode has an areal specific capacity of 4.71C cm at a current density of 3 mA cm (440.19C g at 0.28 A g) and can still maintain 88.76 % of the initial capacitance after 5000 cycles. In addition, the assembled hybrid supercapacitor has an energy density of 5.59 mWh cm at 39.54 mW cm.
在超级电容器领域，对先进电极材料结构的研究具有重要意义。在此，我们首次通过多步工艺提出了一种新颖的 3D/3D 复合结构，其中 3D 中空 NiCo LDH 纳米笼被固定在 3D 海胆状 CoO 微球上。结果表明，3D CoO 作为一种有效的、稳定的离子扩散通道，而中空 NiCo LDH 提供了丰富的氧化还原活性位点。基于密度泛函理论（DFT）的计算结果表明，CoO@NiCo LDH 异质结构在费米能级附近具有增强的态密度（DOS）和对 OH 的强吸附能力，表明其具有优异的导电性和电化学反应动力学。因此，CoO@NiCo LDH 电极在电流密度为 3 mA cm （在 0.28 A g 时为 440.19 C g）时具有 4.71C cm 的比面积容量，并且在 5000 次循环后仍能保持初始电容的 88.76%。此外，组装后的混合超级电容器在 39.54 mW cm 的功率密度下具有 5.59 mWh cm 的能量密度。
