Electrodeposited NiFe2Se4 on Nickel Foam as a Binder-Free Electrode for High-Performance Asymmetric Supercapacitors

A FeCo-Se@NiCo-PO4 Electrode Designed by Hierarchical Strategy for Supercapacitors and NiCo//Bi Batteries

In this work, FeCo-Se and NiCo-PO4 were electrodeposited on nickel foam (NF) successively to prepare a cathode material for asymmetric supercapacitors (ASCs) and NiCo//Bi batteries. FeCo-Se@NiCo-PO4 combines the advantages of transition metal selenides (TMSs) and transition metal phosphates (TMPs). FeCo-Se electrodeposited in the underlying layer can facilitate electron transfer for higher conductivity. NiCo-PO4 in the outer layer can facilitate OH- ions diffusion because TMPs can be intercalated into ions readily and the outer robust P-O bond of TMPs can stabilize the structure. Precisely because the hierarchical structure maximizes the synergy between FeCo-Se and NiCo-PO4, FeCo-Se@NiCo-PO4 delivers a rapid electron/ion transfer capability and superior electrochemical performance. The FeCo-Se@NiCo-PO4 exhibits a high specific capacitance of 2221.5 F g-1 (888.6 C g-1) at 1 A g-1. Its aqueous ASC shows specific capacitance of 115.8 F g-1 at 1 A g-1 and all-solid-state ASC presents high reversibility. Its aqueous NiCo//Bi battery has superior durability of about 60% capacity retention and 98% Coulombic efficiency after 2300 cycles. And its all-solid-state NiCo//Bi battery possesses a higher energy density and power density.

Recent Developments in Electrodeposition of Transition Metal Chalcogenides-Based Electrode Materials for Advance Supercapacitor Applications: A Review

High-performance supercapacitive electrode materials have received significant attention from researchers worldwide, thus aiming for comparable performance similar to the extensively used rechargeable batteries. For emerging energy storage technologies like flexible supercapacitors, transition metal chalcogenides (TMCs) have been in the spotlight due to their promising electrochemical features compared to other electrode materials. Among the synthesis techniques, electrodeposition-mediated preparation of thin films of TMCs offered an affordable binder-free approach for electrode fabrication that effectively improved the supercapacitor performance. Hence, this review mainly focussed on the electrodeposition-based syntheses of single/ multinary chalcogenides and their composites for supercapacitors applications. Further, the effects of different deposition parameters were discussed for boosting the supercapacitor performance. Finally, this review outlined the existing challenges and future perspectives in this research domain, which will assist the upcoming exploration in the energy storage field.

Multifunctional metal selenide-based materials synthesized via a one-pot solvothermal approach for electrochemical energy storage and conversion applications

Highly-efficient electroactive materials with distinctive electrochemical features, along with suitable strategies to prepare hetero-nanoarchitectures incorporating two or more transition metal selenides, are currently required to increase charge storage ability. Herein, a one-pot solvothermal approach is used to develop iron-nickel selenide spring-lawn-like architectures (FeNiSe SLAs) on nickel (Ni) foam. The porous Ni foam scaffold not only enables the uniform growth of FeNiSe SLAs but also serves as an Ni source. The effect of reaction time on their morphological and electrochemical properties is investigated. The FeNiSe-15 h electrode shows high areal capacity (493.2 μA h cm-2) and superior cycling constancy. The as-assembled aqueous hybrid cell (AHC) demonstrates high areal capacity and a decent rate capability of 59.4% (50 mA cm-2). The AHC exhibits good energy and power densities, along with excellent cycling stability. Furthermore, to confirm its practicability, the AHC is employed to drive portable electronic appliances by charging it with wind energy. The electrocatalytic activity of FeNiSe-based materials to complete the oxygen evolution reaction (OER) is explored. Among them, the FeNiSe-15 h catalyst shows good OER performance at a current density of 50 mA cm-2. This general synthesis approach may initiate a strategy of advanced metal selenide-based materials for multifunctional applications.

Mushroom-like cobalt nickle metaphosphate@nickel diselenide core-shell nanorods for asymmetric supercapacitors

Although transition metal metaphosphates (TMPOs) display special physical/chemical features and high theoretical capacities, their applications for supercapacitors (SCs) are still restricted by their low energy densities and inferior cycling stability. Herein, a novel strategy has been proposed to address these issues through in situ construction of cobalt nickle metaphosphate (Co_0.2Ni_0.8(PO₃)₂)@nickel diselenide (NiSe₂) core-shell heterostructure on carbon paper (CP) as a self-supporting flexible electrode for SCs. Particularly, this unique mushroom-like porous nanoarchitecture assembled by one-dimensional (1D) Co_0.2Ni_0.8(PO₃)₂ nanorods and zero-dimensional (0D) NiSe₂ nanospheres can expose abundant active sites and afford multi-dimensional channels, which favors rapid electron ions/electron transfer, accelerates the reaction kinetics, and alleviates volume changes during charging/discharging processes. Profiting from its well-aligned 1D/0D nanostructure and strong synergistic effect between Co_0.2Ni_0.8(PO₃)₂ and NiSe₂, the Co_0.2Ni_0.8(PO₃)₂@NiSe₂/CP electrode delivers a specific capacity of 219.4 mAh/g/0.414 mAh cm^-2 at 1 A/g and good cycling stability with capacity retention of 90.7% after 5000 cycles, outperforming many previously reported TMPO-based electrodes in literature. Impressively, an asymmetric supercapacitor (ASC) device assembled with Co_0.2Ni_0.8(PO₃)₂@NiSe₂ as cathode and porous carbon as anode achieves an energy density of 69.2 Wh kg^-1 at 736.0 W kg^-1 and maintains a capacity retention of 97.6% after 20,000 charge-discharge cycles. This work provides an efficient approach to design multi-dimensional hybrid nanomaterials for high-performance SCs.

H-CoNiSe2/NC dodecahedral hollow structures for high-performance supercapacitors

The synergistic effect between metal ions and increasing the surface area leads to the fabrication of supercapacitor materials with high capacities. It is predicted that transition metal selenide compounds will be ideal electrode materials for supercapacitors. However, the defects of poor conductivity and volume expansion of the compounds are fundamental problems that must be solved. In this work, we successfully synthesized the cobalt-nickel selenide nitrogen-doped carbon (H-CoNiSe₂/NC) hollow polyhedral composite structure using ZIF-67 as a precursor. The CoSe₂ and NiSe₂ nanoparticles embedded in the NC polyhedral framework offer a wealth of active sites for the whole electrode. Moreover, the presence of the NC structure in the proposed composite can simultaneously lead to improved conductivity and reduce the volume effect created during the cycling procedure. The H-CoNiSe₂/NC electrode provides high specific capacity (1131 C/g at 1.0 A/g) and outstanding cyclic stability (90.2% retention after 6000 cycles). In addition, the H-CoNiSe₂/NC//AC hybrid supercapacitor delivers ultrahigh energy density and power density (81.9 Wh/kg at 900 W/kg) and excellent cyclic stability (92.1% of the initial capacitance after 6000 cycles). This study will provide a supercapacitor electrode material with a high specific capacity for energy storage devices.Please confirm the corresponding affiliation for the 'Ali A. Ensafi' author is correctly identified.Error during converting author query response. Please check the eproofing link or feedback pdf for details.

Two-step electrodeposition synthesis of iron cobalt selenide and nickel cobalt phosphate heterostructure for hybrid supercapacitors

Exploring novel heterostructure with multiscale nanoarchitectures and modulated electronic structure is crucial to improve the electrochemical properties of electrode materials for supercapacitors (SCs). In this study, a two-step electrodeposition approach which involves suitable efficient procedures, is leading to in-situ preparation of iron cobalt selenide (Fe0.4Co0.6Se2) @ nickel cobalt phosphate (NiCo(HPO4)2·3H2O, denoted as NiCo-P) hybrid nanostructure on carbon cloth (CC) substrate. Particularly, depositing two-dimensional (2D) NiCo-P nanosheets on the surface of Fe0.4Co0.6Se2 nanobelts results in formation of well-organized Fe0.4Co0.6Se2@NiCo-P nanocomposite with large surface area, hierarchical porous nanoarchitecture as well as numerous electroactive sites, leading to enhanced electroactivity and accelerated mass/electron transfer. Benefiting from its unique nanoarchitecture and synergistic effect of two components, the obtained free-standing Fe0.4Co0.6Se2@NiCo-P electrode demonstrates gravimetric capacity (Cm)/volumetric capacity (Cd) of 202.3 mAh/g/319.6 mAh cm-3 at 1 A g-1 and good cyclic stability (83.9% capacity retention over 5000 cycles), which are superior to those of pure Fe0.4Co0.6Se2 and NiCo-P electrodes. Impressively, it was established that an aqueous hybrid supercapacitor (HSC) based on Fe0.4Co0.6Se2@NiCo-P and rape pollen derived hierarchical porous carbon (RPHPC) achieves gravimetric energy density (Em)/volumetric energy density (Ed) of 64.4 Wh kg-1/10.7 mWh cm-3 and a long cycle life with 90.3% capacity retention over 10,000 cycles. This report offers a perspective to design selenide/phosphate heterostructure on conducting substrate for electrochemical energy storage applications.

1D-on-1D core-shell cobalt iron selenide @ cobalt nickel carbonate hydroxide hybrid nanowire arrays as advanced battery-type supercapacitor electrode

Sluggish kinetics and poor structural stability are two main obstacles hampering the exploration of transition metal selenides (TMSs) for supercapacitor. Developing a reasonable core-shell heterostructure with unique morphology is an effective approach to resolve these issues. Herein, a core-shell cobalt iron selenide (CoFe₂Se₄) @ cobalt nickel carbonate hydroxide (CoNi-CH) heterostructure is directly fabricated on carbon cloth via an electrodeposition method followed by a hydrothermal reaction. In this well-defined heterostructure, one-dimensional (1D) CoFe₂Se₄ nanowires function as the cores and CoNi-CH nanowires as the shells, which combines the merits of highly conductive CoFe₂Se₄ for rapid electron transfer and highly electroactive CoNi-CH for multiple redox reactions. Further, the intimate interaction between CoNi-CH and CoFe₂Se₄ realizes large surface area with hierarchical network and generates rich heterointerfaces with modified the electronic structure. By virtue of its facile 1D-on-1D nanoarchitecture and synergistic effect, the CoFe₂Se₄@CoNi-CH electrode delivers a increased specific capacity of 218.6 mAh g^-1 at 1 A^-1 and enhanced rate capability (65.5% at 20 A g^-1) compared with pure CoFe₂Se₄ and CoNi-CH. Besides, a hybrid supercapacitor is established by coupling CoFe₂Se₄@CoNi-CH cathode and porous carbon anode, which enjoys a maximum energy density of 67.3 Wh kg^-1 at 765.9 W kg^-1 and prominent durability with 85.4% of capacity retention over 20,000 cycles.

Nanostructure Nickel-Based Selenides as Cathode Materials for Hybrid Battery-Supercapacitors

Supercapacitors (SCs) have attracted many attentions and already became part of some high-power derived devices such as Tesla's electric cars because of their higher power density. Among all types of electrical energy storage devices, battery-supercapacitors are the most promising for superior performance characteristics, including short charging time, high power density, safety, easy fabrication procedures, and long operational life. An SC usually consists of two foremost components, namely electrode materials, and electrolyte. The selection of appropriate electrode materials with rational nanostructured designs have resulted in improved electrochemical properties for high performance and has reduced the cost of SCs. In this review, we mainly spotlight the nickel-based selenides nanostructured which applied as high-performance cathode materials for SCs. Different nickel-based selenides materials are highlighted in various categories, such as nickel-cobalt-based bimetallic chalcogenides and nickel-M based selenides. Also, we mentioned material modification for this material type. Finally, the designing strategy and future improvements on nickel-based selenides materials for the application of SCs are also discussed.