Rational Design of Porous Structured Nickel Manganese Sulfides Hexagonal Sheets‐in‐Cage Structures as an Advanced Electrode Material for High‐Performance Electrochemical Capacitors

• Published in: Chemistry : a European journal 2020-02, Vol.26 (10), p.2251-2262
• Main Authors: Khalafallah, Diab, Wu, Zongxiao, Zhi, Mingjia, Hong, Zhanglian
• Format: Article
• Language: English
• Subjects: asymmetric supercapacitors; Cages; Capacitance; Charge materials; Charge transfer; Chemistry; Current density; Electrical conductivity; Electrical resistivity; Electrochemistry; Electrode materials; Electrodes; energy-storage materials; Flux density; Manganese; Nickel; nickel–manganese sulfides; Open spaces; Redox reactions; Sheets; Sulfides; Supercapacitors; Synergistic effect; synergistic effects
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.201904991

The design of hierarchical electrodes comprising multiple components with a high electrical conductivity and a large specific surface area has been recognized as a feasible strategy to remarkably boost pseudocapacitors. Herein, we delineate hexagonal sheets‐in‐cage shaped nickel–manganese sulfides (Ni‐Mn‐S) with nanosized open spaces for supercapacitor applications to realize faster redox reactions and a lower charge‐transfer resistance with a markedly enhanced specific capacitance. The hybrid was facilely prepared through a two‐step hydrothermal method. Benefiting from the synergistic effect between Ni and Mn active sites with the improvement of both ionic and electric conductivity, the resulting Ni‐Mn‐S hybrid displays a high specific capacitance of 1664 F g−1 at a current density of 1 A g−1 and a capacitance of 785 F g−1 is maintained at a current density of 50 A g−1, revealing an outstanding capacity and rate performance. The asymmetric supercapacitor device assembled with the Ni‐Mn‐S hexagonal sheets‐in‐cage as the positive electrode delivers a maximum energy density of 40.4 Wh kg−1 at a power density of 750 W kg−1. Impressively, the cycling retention of the as‐fabricated device after 10 000 cycles at a current density of 10 A g−1 reaches 85.5 %. Thus, this hybrid with superior capacitive performance holds great potential as an effective charge‐storage material. The six is in: A hexagonal sheets‐in‐cage shaped nickel–manganese sulfide (Ni‐Mn‐S) composite with a unique porous feature is employed as an advanced electrode material with a high specific capacitance and excellent rate capability. As a hybrid asymmetric capacitor electrode, the established device achieves high power and energy densities with an outstanding cycling stability for 10 000 consecutive cycles of repeated charge/discharge processes. This composite holds great potential as a multifunctional material for energy storage.