You Jianghong, Yuan Yiming, Zhang Chen, Xu Haoming, Chen Mingyao, Wang Ying, Chen Dongsheng
College of Mathematics and Physics, Shanghai University of Electric Power, Shanghai 200090, PR China.
College of Mathematics and Physics, Shanghai University of Electric Power, Shanghai 200090, PR China.
J Colloid Interface Sci. 2025 Nov 15;698:138011. doi: 10.1016/j.jcis.2025.138011. Epub 2025 May 30.
The transition metal oxide of nickel cobaltite (NiCoO) has gained more and more attention from battery industry for its excellent properties of high capacitance and cycling stability. However, its performance when used in supercapacitors is compromised due to its limited active sites and poor conductivity. Herein, a 3D (three-dimensional) hierarchical and high-performance material of NiCoO@MXene@LDH (LDH: layered double hydroxide) composite was designed and synthesized. In the material, NiCoO nanorods form a skeleton of nanosheet arrays on layered MXene; and on the nanosheet arrays, NiCo-LDH nanoparticles are attached to form a 3D hierarchical structure, extending the electrochemically active sites, suppressing the agglomeration of NiCo-LDH and producing hierarchical channels that promote electron and ion transport. Density functional theory (DFT) calculations and the results of Ultraviolet-visible (UV-Vis) spectrophotometry indicated that the introduction of MXene and NiCo-LDH induces a redistribution of the electronic states of NiCoO due to the formation of a heterointerface, thereby decreasing its bandgap by about 1.42 eV. The X-ray photoelectron spectroscopy (XPS) analysis further demonstrated the negative shift in the initial binding energies of nickel (Ni) and cobalt (Co) atoms, which is due to their transition of spin states; and this is in agreement with the high intensity of electron paramagnetic resonance (EPR) peak in the NiCoO@MXene@LDH composite. The in situ Raman analysis reveals that the enhanced energy storage performance originates from the accelerated formation and increased exposure of NiCoOOH active species during electrochemical cycling. The synergistic effect of MXene and NiCo-LDH introduced into NiCoO enhanced the supercapacitor in terms of power and energy densities. It was indicated that the supercapacitor fabricated from NiCoO@MXene@LDH supercapacitor exhibited a specific capacitance of 5066 F g at 1 A g, and a capacitance retention of 97.82 % after 10,000 charge cycles at 10 A g. Moreover, an asymmetric supercapacitor (ASC) device with a NiCoO@MXene@LDH//AC configuration was developed. The supercapacitor presented an energy density and power density of 70.11 Wh kg and 850.22 W kg, respectively. The redistribution of electronic states and decreased bandgap could facilitate the creation of NiCoO-based materials with customized features for supercapacitors.
镍钴矿过渡金属氧化物（NiCoO）因其高电容和循环稳定性等优异性能而越来越受到电池行业的关注。然而，由于其活性位点有限且导电性差，其在超级电容器中的性能受到影响。在此，设计并合成了一种三维（3D）分级高性能材料NiCoO@MXene@LDH（LDH：层状双氢氧化物）复合材料。在该材料中，NiCoO纳米棒在层状MXene上形成纳米片阵列骨架；在纳米片阵列上，附着NiCo-LDH纳米颗粒以形成3D分级结构，扩展了电化学活性位点，抑制了NiCo-LDH的团聚，并产生了促进电子和离子传输的分级通道。密度泛函理论（DFT）计算和紫外可见（UV-Vis）分光光度法结果表明，由于异质界面的形成，MXene和NiCo-LDH的引入导致NiCoO电子态重新分布，从而使其带隙降低约1.42 eV。X射线光电子能谱（XPS）分析进一步证明了镍（Ni）和钴（Co）原子初始结合能的负移，这是由于它们的自旋态转变；这与NiCoO@MXene@LDH复合材料中电子顺磁共振（EPR）峰的高强度一致。原位拉曼分析表明，储能性能的增强源于电化学循环过程中NiCoOOH活性物种的加速形成和暴露增加。引入NiCoO中的MXene和NiCo-LDH的协同效应在功率和能量密度方面增强了超级电容器。结果表明，由NiCoO@MXene@LDH超级电容器制备的超级电容器在1 A g时的比电容为5066 F g，在10 A g下进行10000次充放电循环后的电容保持率为97.82%。此外，还开发了一种具有NiCoO@MXene@LDH//AC配置的非对称超级电容器（ASC）器件。该超级电容器的能量密度和功率密度分别为70.11 Wh kg和850.22 W kg。电子态的重新分布和带隙的降低有助于制备具有定制特性的基于NiCoO的超级电容器材料。
