Coaxial Ni_xCo_2x(OH)_6x/TiN Nanotube Arrays as Supercapacitor Electrodes

Abstract

NixCo2x(OH)6x, as a precursor of intensively studied NiCo2O4, has been directly deposited into self-standing titanium nitride nanotube array (TiN NTA) grid monolithic supports to form a coaxial nanostructured electrode for supercapacitors. With TiN NTA substrates providing a large surface area, fast electron transport, and enhanced structure stability, this NixCo2x(OH)6x/TiN electrode exhibits superior pseudocapacitive performance with a high specific capacitance of 2543 F g(-1) at 5 mV s(-1), remarkable rate performance of 660 F g(-1) even at 500 mV s(-1), and promising cycle performance (about 6.25% capacitance loss for 5000 cycles). Interestingly, the NixCo2x(OH)6x/TiN NTA electrode outperforms the NiCo2O4/TiN NTA electrode, indicating that this self-standing NixCo2x(OH)6x/TiN NTA monolith is a promising candidate for high-performance supercapacitor applications.

All Metal Nitrides Solid‐State Asymmetric Supercapacitors

“…Among all the reported metal nitrides in energy storage, TiN and Fe 2 N received particular attention due to their high capacitance (Fe 2 N as lithium ion battery anode: ≈900 mAh g −1 ; TiN as supercapacitor cathode: ≈150 F g −1 ) and electrical conductivity. [ 15,16 ] Various types of TiN nanostructures have been employed as supercapacitive electrode such as nanoparticle, [ 13 ] nanotube, [17][18][19] mesoporous microsphere, [ 20 ] and nanosheets. [ 21 ] However, TiN was found to be easily oxidized in aqueous solutions …”

Ni@NiO core/shell dendrites for ultra-long cycle life electrochemical energy storage

“…18 Apart from the above methods, electrodeposition has gained more and more attention because the electroactive material can be directly grown on a current collector without the need for using any binder or conducting agent. 20 Flaky Ni 3 S 2 (ref. 21) 3D concentration-gradient nickel-cobalt hydroxide nanostructures, 22 nickel-cobalt hydroxide nano-networks, 23 NiO nanotube based interconnected NiO nanoakes, 24 and ternary Ni-Co-Cu oxyhydroxide nanosheets 25 have been successfully synthesized by electrodeposition and proved promising for EESDs.…”

“…26 Another problem facing the nickelbased electrode material is its low electrical conductivity, which not only restricts the power performance but also prevents the utilization of thick electrodes. 2,24 One feasible approach to this problem is to electrodeposit nanosized active materials over a 3D conductive framework to form hybrid nanostructures, such as coaxial Ni x Co 2x (OH) 6x /TiN nanotube arrays, 20 hierarchical TiN@Ni(OH) 2 core/shell nanowire arrays, 27 and ITO/NiO nanowires. 28 Both the specic capacitance and power density can be improved as expected.…”

“…Moreover, the preparation of 3D conductive networks complicates the processing procedure and impairs the electrode fabrication efficiency. 20 Hence, it is still challenging to prepare nickel-based electrodes with both high capacity and excellent stability by electrodeposition.…”

Design and synthesis of H-TiO2/MnO2 core–shell nanotube arrays with high capacitance and cycling stability for supercapacitors

“…Therefore, the main challenge for TMOs is to enhance their conductivities for simultaneously exerting the potentials of high-density energy as batteries and fast power delivery as electrolytic capacitors [19,20]. For the sake of the utilization improvement and the overall performing optimization of pseudocapacitive materials, a sagacious and attractive concept for binder-free electrodes of supercapacitors is emerging, which directly synthesizes high-capacitance pseudocapacitive materials on highly conductive reinforcement with integrated array architectures [21][22][23][24][25]. Via this construction, many competitive factors are simultaneously advantageous to obtain high specific capacitance, ideal rate performance and cycle life span, which are abundant accessible electroactive sites, direct ion transport pathways, efficient electron collection and even multi-functionalities of components.…”