Neoteric hollow tubular MnS/Co3S4 hybrids as high-performance electrode materials for supercapacitors

Electrochemically Deposited MoS2 and MnS Multilayers on Nickel Substrates in Inverse Opal Structure as Supercapacitor Microelectrodes

High-dispersion polystyrene (PS) microspheres with monodispersity were successfully synthesized by the non-emulsification polymerization method, and three-dimensional (3D) photonic crystals of PS microspheres were fabricated by electrophoretic self-assembly (EPSA). The metal nickel inverse opal structure (IOS) photonic crystal, of which the structural thickness can be freely adjusted via electrochemical deposition (ECD), and subsequently, MnS/MoS₂/Ni-IOS specimens were also prepared by ECD. Excellent specific capacitance values (1880 F/g) were obtained at a charge current density of 5 A/g. The samples in this experiment were tested for 2000 cycles of cycle life and still retained a reasonably good level of 76.6% of their initial capacitance value. In this study, the inverse opal structure photonic crystal substrate was used as the starting point, and then the microelectrode material for the MnS/MoS₂/Ni-IOS supercapacitor was synthesized. Our findings show that the MnS/MoS₂/Ni-IOS microelectrode makes a viable technical contribution to the design and fabrication of high-performance supercapacitors.

New nickel-rich ternary carbonate hydroxide two-dimensional porous sheets for high-performance aqueous asymmetric supercapattery

Transition metal carbonate hydroxides (M-CHs) are promising candidates for electrode materials in supercapattery, due to their low-cost preparation and high-energy features. However, they also suffer from ionic kinetics bottlenecks without efficient morphological design. Tailoring the chemical compositions and nanostructures of electrode materials to realize high performance is significant for meeting the current demand for electrical energy storage devices. Therefore, we present a simple hydrothermal method for constructing better electrochemically active M-CHs with ternary metal components and hierarchical nanostructures that are assembled by interwoven nanosheets. Benefiting from higher contents of Ni species and superior two-dimensional/three-dimensional (2D/3D) pore structures, the fabricated cobalt-nickel-zinc carbonate hydroxides with Co/Ni/Zn molar ratios of 2:3:1 (CoNiZn-231) delivered the best specific capacity of 1130.8 C g^-1 at 1 A g^-1, decent rate performance (67.2% in 1-10 A g^-1), and excellent cycling performance (92.6% over 10,000 cycles) in comparison with the majority of mono/bimetallic materials. Then, an alkaline hybrid (CoNiZn-231//activated carbon (AC)) device is developed, which shows a high energy density of 31.62 Wh kg^-1 at a power density of 646 W kg^-1 and an excellent capacity retention of 99.27% after 10,000 cycles. Herein, the rational design of trimetallic compositions and hierarchical structures of carbonate hydroxides is described, which provides good choices for the synthesis of high-performance electrode materials in electrochemical energy storage applications.