NiCo2S4 Nanotube Research Articles

Construction of desirable NiCo2S4 nanotube arrays on nickel foam substrate for pseudocapacitors with enhanced performance

Ternary NiCo2O4 synthesized via annealing NiCo-precursor has been extensively studied as an advanced electrode material for high-performance supercapacitors. In this work, we demonstrate a facile hydrothermal synthesis of NiCo2S4 nanotube arrays (NTAs) by simply treating the NiCo-precursor with Na2S solution based on the Kirkendall effect. The NiCo2S4 NTAs grown on nickel foam substrate are directly evaluated as binder-free electrode for supercapacitors. Impressively, the NiCo2S4 NTA electrode delivers an ultrahigh capacitance of 15.58F cm−2 at a current density of 10mAcm−2, which is much higher than 3.63F cm−2 of the mesoporous NiCo2O4 nanowire array (NWA) electrode. In addition, the NiCo2S4 NTA electrode also exhibits good cycling stability with 79.3% capacitance retention at high current density of 60mAcm−2 after 2000 cycles. In view of the excellent electrochemical performance and the facile and cost-effective synthesis, such NiCo2S4 NTA electrode would hold great promise for high-performance supercapacitor applications in future.

Direct Growth of NiCo2S4 Nanotube Arrays on Nickel Foam as High‐Performance Binder‐Free Electrodes for Supercapacitors

Arrays of NiCo2 S4 nanotubes on nickel foam were prepared by means of a two-step method, and were directly applied as a binder-free supercapacitor electrode. Such a binder-free method enables intimate contact between the current collector and the active materials, and can effectively improve ion and charge transportation. As a result, the electrochemical performances of supercapacitors can be improved. The as-prepared NiCo2 S4 nanotubes/Ni foam electrode shows a high specific capacitance (738 F g-1 at 4 A g-1 ), excellent rate capability (78 % capacitance retention at 32 A g-1 ), and good cycling stability (retention capacity of 93.4 % after 4000 cycles), which suggests its promising application for electrochemical capacitors.

Design Hierarchical Electrodes with Highly Conductive NiCo2S4 Nanotube Arrays Grown on Carbon Fiber Paper for High-Performance Pseudocapacitors

We report on the development of highly conductive NiCo2S4 single crystalline nanotube arrays grown on a flexible carbon fiber paper (CFP), which can serve not only as a good pseudocapacitive material but also as a three-dimensional (3D) conductive scaffold for loading additional electroactive materials. The resulting pseudocapacitive electrode is found to be superior to that based on the sibling NiCo2O4 nanorod arrays, which are currently used in supercapacitor research due to the much higher electrical conductivity of NiCo2S4. A series of electroactive metal oxide materials, including CoxNi1-x(OH)2, MnO2, and FeOOH, were deposited on the NiCo2S4 nanotube arrays by facile electrodeposition and their pseudocapacitive properties were explored. Remarkably, the as-formed CoxNi1-x(OH)2/NiCo2S4 nanotube array electrodes showed the highest discharge areal capacitance (2.86 F cm(-2) at 4 mA cm(-2)), good rate capability (still 2.41 F cm(-2) at 20 mA cm(-2)), and excellent cycling stability (∼ 4% loss after the repetitive 2000 cycles at a charge-discharge current density of 10 mA cm(-2)).

In situ growth of NiCo2S4 nanotube arrays on Ni foam for supercapacitors: Maximizing utilization efficiency at high mass loading to achieve ultrahigh areal pseudocapacitance

Self-standing NiCo2S4 nanotube arrays have been in situ grown on Ni foam by the anion-exchange reaction and directly used as the electrode for supercapacitors. The NiCo2S4 nanotube in the arrays effectively reduces the inactive material and increases the electroactive surface area because of the ultrathin wall, which is quite competent to achieve high utilization efficiency at high electroactive materials mass loading. The NiCo2S4 nanotube arrays hybrid electrode exhibits an ultrahigh specific capacitance of 14.39 F cm−2 at 5 mA cm−2 with excellent rate performance (67.7% retention for current increases 30 times) and cycling stability (92% retention after 5000 cycles) at a high mass loading of 6 mg cm−2. High areal capacitance (4.68 F cm−2 at 10 mA cm−2), high energy density (31.5 Wh kg−1 at 156.6 W kg−1) and high power density (2348.5 W kg−1 at 16.6 Wh kg−1) can be achieved by assembling asymmetric supercapacitor with reduced graphene oxide at a total active material mass loading as high as 49.5 mg. This work demonstrates that NiCo2S4 nanotube arrays structure is a superior electroactive material for high-performance supercapacitors even at a mass loading of potential application-specific scale.

NiCo2S4 porous nanotubes synthesis via sacrificial templates: high-performance electrode materials of supercapacitors

NiCo2S4 porous nanotubes are synthesised by a sacrificial template method based on the Kirkendall effect. The as-prepared NiCo2S4 nanotube electrode shows a specific capacitance of 1093 F g−1 at a current density of 0.2 A g−1 (933 F g−1 at 1 A g−1).