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While metal sulfides have extensively investigated as electrode materials for supercapacitors, the further optimization of their material system is still necessary to achieve satisfied performance. In this work, we reported the synthesis of ternary metal sulfide SnNiCoS and its application as electrode material of asymmetric supercapacitors, in which active carbon is used as the other electrode. For control experiments, asymmetric supercapacitors based on single metal sulfide CoS and binary metal sulfide NiCoS are also fabricated and investigated. The results show that the nanospherical SnNiCoS achieves the best performance. Ternary sulphide materials offer more redox than corresponding single-metal sulphides due to the synergy among various transition metal elements. The specific capacitance is 18.6 F cm−2 at current density of 5 mA·cm−2. An energy density of 937.2 μ Wh cm−2 is achieved at a power density of 4000 μ W·cm−2. After 8000 cycles, the capacity retention rate is 82.9%. Present work indicates that SnNiCoS ternary metal sulfide could be a promising composite for high performance supercapacitors. [ABSTRACT FROM AUTHOR]

While supercapacitors have been widely studied as the next generation of energy storage devices, to develop active electrode materials for enhancing device performance is still challenging. Herein, we fabricated asymmetric supercapacitors based on NiZn-Layered double hydroxide (LDH) @NiCoSe2 hierarchical nanostructures as electrode materials. The NiZn-LDH@NiCoSe2 composites are deposited on Ni foam by a two-step strategy, in which NiZn-LDH nanosheets were firstly grown on Ni foam by hydrothermal method, and then NiCoSe2 particles were prepared by electrodeposition. Due to the synergistic effect between NiZn-LDH and NiCoSe2, excellent device performance was achieved. In a three-electrode system, the NiZn-LDH@NiCoSe2 exhibits a specific capacitance of 2980 F gâˆ'1 at 1 A gâˆ'1. Furthermore, the asymmetric supercapacitor of NiZn-LDH@NiCoSe2//activated carbon (AC) device was assembled, which exhibits the energy density of 49.2 Wh kgâˆ'1 at the power density of 160 W kgâˆ'1, with the capacity retention rate is 91% after 8000 cycles. The results indicates that NiZn-LDH@NiCoSe2 is a promising candidate as electrode materials for efficient energy storage devices. [ABSTRACT FROM AUTHOR]

Zn-ion hybrid supercapacitors (ZSC) have shown great potential as energy storage devices as they incorporate the merits of rechargeable batteries and supercapacitors. However, the poor bendability, unsatisfied energy density and cycling stability are still challenging the practical application of ZSC. Herein, Zn-doped MnO 2 nanowires (Zn-MnO 2) binder-free cathodes is synthesized with the aid of a one-step hydrothermal approach, which improves the lattice distortion caused by Zn hydrate ions and provided rich ion transport path. The Zn-MnO 2 cathode was assembled with the active carbon (AC) anode into an axial ZSC, achieving a surface capacitance of 1300 mF cm−2 and an energy density of 722.2 μWh cm−2 at power density of 1.99 mW cm−2. After 20,000 charge/discharge cycles, a capacity retention rate of 83.75% and a coulombic efficiency of 100% were achieved, indicating excellent cycle stability of present device. In addition, this axial ZSC reveals exquisite mechanical flexibility and electrochemical stability, enabling continuously power smartphones under bending conditions. Present work suggests that ZSC devices based on Zn-MnO 2 have excellent doable for business energy storage devices. • A axial ZSC was designed with Zn-doped MnO 2 cathode and carbon material anode. • The axial structure improves the flexibility and stability of the ZSC device. • The ZSC device displays high energy density (722.2 μWh cm−2). • The fiber-type device can be applied as wearable bracelet power supply device. [ABSTRACT FROM AUTHOR]

Nickel-Cobalt layered double hydroxide (NiCo-LDH) nanosheets have the advantages of large interlayer spacing, adjustable structure, and high theoretical capacity, which has attracted extensive attention. However, the poor conductivity and structural instability limit their application in electrode materials. Herein, a high-performance all-solid-state asymmetric supercapacitor (ASC) is designed with AC as the anode and Ni 3 S 2 @NiCo-LDH as the cathode. The open Ni 3 S 2 @NiCo-LDH cross-linked nanosheets arrays are uniformly arranged on the Ni foam (NF), which not only increases the sufficient contact area between electrode and electrolyte, but also facilitates the rapid transfer of electrons. Therefore, the assembled ASC exhibits high area-specific capacitance of 1267.2 mF cm−2 at 5 mA cm−2, high energy density of 450.60 μW h cm−2 at the power density of 3.99 mW cm−2, and excellent cyclic stability with 85.2 % capacity retention over 5000 cycles. This work demonstrates the feasibility of the cross-linked nanosheets arrays of Ni 3 S 2 @NiCo-LDH on NF, which shows great potential as electrode for novel energy storage devices. • Ni 3 S 2 @NiCo-LDH/NF and AC/NF are prepared as electrodes. • The cross-linked nanosheet array structure improves the electrical conductivity and specific capacitance of electrodes. • The Ni 3 S 2 @NiCo-LDH composites deliver a high energy density for the all-solid-state asymmetric supercapacitor. • The device exhibits great potential as high-performance energy storage devices. [ABSTRACT FROM AUTHOR]

• A simple and fast hydrothermal synthesis method was proposed in this paper to synthesize an electrode material with a heterostructure of NiMoO 4 nanoneedles and high-performance flower-shaped NiCoZn-LDH on a foam nickel substrate. • The electrochemical performance of the NiCoZn-LDH@NMO@NF nanoneedle composite electrode material, treated with CTAB, is significantly superior to that of the untreated NiMoO 4 @NF electrode. • It shows excellent electrochemical properties, including a specific capacitance of 3541 mF/cm2 in KOH solution and an outstanding capacity retention of 83.04 % after 10,000 cycles. Transition metal hydroxides have attracted wide attention as promising composite nanomaterials due to their numerous active sites and large specific surface areas. In this study, a two-step hydrothermal synthesis method is proposed to generate a heterostructure (NiCoZn-LDH@NiMoO 4 @NF) consisting of nanoflowers coated with nanoneedles on a foam nickel substrate. The aggregation issue of NiCoZn-LDH is effectively improved by immersing it in CTAB solution after one-step hydrothermal synthesis of NiMoO 4 nanoneedles on Ni Foam (NF). The heterostructure between NiMoO 4 nanoneedles and NiCoZn-LDH significantly enhances the material stability and electrochemical performance. Activated carbon is used as the negative electrode, and the NiCoZn-LDH@NiMoO 4 @NF composite material is used as the positive electrode to assemble an asymmetric supercapacitor (ASC) device for electrochemical testing. The device exhibits a specific capacitance of 3541 mF/cm2 at a current density of 6 mA/cm2. Furthermore, the capacity retention rate remains at 83.04 % after 10,000 cycles of charge and discharge, and a high specific energy density of 0.735 mWh/cm2 is achieved at a power density of 1.6 mW/cm2. The experimental results demonstrate that transition metal hydroxides play a crucial role in enhancing the electrochemical performance of supercapacitors. This study provides new insights into Supercapacitor (SC) active materials and offers a promising experimental approach for synthesizing new nanomaterials. [ABSTRACT FROM AUTHOR]