Metal organic frameworks derived Ni-doped hierarchical NiXCo1-XS@C bundled-like nanostructures for enhanced supercapacitors

• Published in: Electrochimica acta 2022-02, Vol.406, p.139872, Article 139872
• Main Authors: Huang, Chen, Gao, Aimei, Zhu, Zhenhua, Yi, Fenyun, Wang, Mengyi, Hao, Junnan, Cheng, Honghong, Ling, Jingzhou, Shu, Dong
• Format: Article
• Language: English
• Subjects: Adsorption; Density functional theory; DFT calculations; Doping; Electrode materials; Electrodes; Electronic structure; Flux density; Metal-organic frameworks; Nanoparticles; Nanostructure; Ni-Co-MOF; Ni-doped; Nickel; NiXCo1-XS/C; Reaction kinetics; Redox reactions; Supercapacitors
• ISSN: 0013-4686; 1873-3859
• DOI: 10.1016/j.electacta.2022.139872

•3D bundle-like structure Ni-Co-MOF were prepared via doping metal external atoms strategy.•Reported Ni-doped compound as efficient electrode material for supercapacitor.•Novel NiXCo1-XS/C-X (X = 1,3,5) bundle-like structure with different ration Ni-doped were fabricated successfully.•NiXCo1-XS/C-3 shows high specific capacitance and excellent cycle stability.•DFT calculations confirm that NiXCo1-XS posses high OH− adsorption. Metal-organic frameworks (MOFs) and their derivatives in the area of energy store have received extensive attention. Here, 3D hierarchical bundle-like micro/nanostructure Ni-Co-MOFs were designed via a co-precipitation and external metal-atom doping strategy. Based on the distinctive precursor, a carbon coated Ni-Co-S nanoparticles were prepared through a two-step thermal annealing. The Ni doping into CoS can both regulates electronic structure and stabilizes Co species as electrode material for supercapacitor. By optimizing the content of Ni-doping, the fabricated NiXCo1-XS/C-3 with 25% Ni-doping shows remarkable specific capacitance (709 C/g at 1 A/g), superior rate capability and excellent cycling stability. An asymmetric supercapacitor with an energy density of 45.3 Wh/kg was acquired successfully in two-electrode system. NiXCo1-XS possess a high OH− adsorption energy compared to single NiS and CoS was proved by density functional theory calculations. Strong OH− adsorption ability is conducive to capture electrolyte ions, which leads to rapid redox reaction kinetics. In addition, this work provides new ideas for how to design metal sulfide-based supercapacitor positive electrode materials. Hierarchical bundle-like nanostructures NiXCo1-XS@C was synthesized via doping external metal atoms strategy and thermal annealing. Further optimize the electrochemical performance of electrode materials by adjusting the content of Ni doping, resulting from the special 3D bundle-like structure and appropriate Ni-doping, NiXCo1-XS/C-3 delivers excellent electrochemical performance in both three-electrode and two-electrode systems. [Display omitted]