Exploring the potential of CuCoFeTe@CuCoTe yolk-shelled microrods in supercapacitor applications.

Driven by their excellent conductivity and redox properties, metal tellurides (MTes) are increasingly capturing the spotlight across various fields. These properties position MTes as favorable materials for next-generation electrochemical devices. Herein, we introduce a novel, self-sustained approach to creating a yolk-shelled electrode material. Our process begins with a metal-organic framework, specifically a CoFe-layered double hydroxide-zeolitic imidazolate framework67 (ZIF67) yolk-shelled structure (CFLDH-ZIF67). This structure is synthesized in a single step and transformed into CuCoLDH nanocages. The resulting CuCoFeLDH-CuCoLDH yolk-shelled microrods (CCFLDH-CCLDHYSMRs) are formed through an ion-exchange reaction. These are then converted into CuCoFeTe-CuCoTe yolk-shelled microrods (CCFT-CCTYSMRs) by a tellurization reaction. Benefiting from their structural and compositional advantages, the CCFT-CCTYSMR electrode demonstrates superior performance. It exhibits a fabulous capacity of 1512 C g-1 and maintains an impressive 84.45% capacity retention at 45 A g-1. Additionally, it shows a remarkable capacity retention of 91.86% after 10 000 cycles. A significant achievement of this research is the development of an activated carbon (AC)||CCFT-CCTYSMR hybrid supercapacitor. This supercapacitor achieves a good energy density (Eden) of 63.46 W h kg-1 at a power density (Pden) of 803.80 W kg-1 and retains 88.95% of its capacity after 10 000 cycles. These results highlight the potential of telluride-based materials in advanced energy storage applications, marking a step forward in the development of high-energy, long-life hybrid supercapacitors.

Fabrication of nanosheet-assembled hollow copper-nickel phosphide spheres embedded in reduced graphene oxide texture for hybrid supercapacitors.

Owing to their metalloid characteristics with high electrical conductivity, transition metal phosphides (TMPs) have attracted considerable research attention as prospective cathodes for hybrid supercapacitors. Unfortunately, they usually exhibit low rate performance as well as poor longevity, which does not meet the demands of hybrid supercapacitors. The nanocomposite constructed from reduced graphene oxide (rGO) and TMPs with a highly porous nature can effectively overcome the above-mentioned issues, greatly widening their utilization. In this work, we fabricated nanosheet-assembled hollow copper-nickel phosphide spheres (NH-CNPSs) by the controllable phosphatizing of copper-nickel-ethylene glycol (CN-EG) precursors. Then, porous NH-CNPSs were embedded in rGO texture (NH-CNPS-rGO) to form a unique porous nanoarchitecture. The obtained NH-CNPS-rGO has several advantages benefiting as the cathode electrode, such as (i) the hollow structure as well as porous nanosheets are conducive to fast electrolyte diffusion, (ii) the electrical conductivity of NH-CNPS is further enhanced when coupled with the rGO texture, hence promoting electron transfer in the whole structure, (iii) wrapping NH-CNPSs within the rGO texture endows the nanocomposite with much better structural stability, resulting in longer durability of the electrode, And (iv) the porous structures generated in the nanocomposite provide a perfect space for reducing the mass transfer resistance and accessing the electrolyte, thereby boosting the reaction kinetics. The tests demonstrated that the optimal NH-CNPS-rGO electrode revealed a capacity of up to 1075 C g-1, a superior rate capacity, and exceptional longevity of 94.7%. Moreover, a hybrid supercapacitor (NH-CNPS-rGO‖AC) equipped with the NH-CNPS-rGO-cathode electrode and activated carbon (AC)-anode electrode represented a satisfactory energy density of 64 W h kg-1 at 801 W kg-1 and amazing longevity (91.8% retention after 13 000 cycles), which endorses the promising potential of NH-CNPS-rGO for high-efficiency supercapacitors. This research showcases an appropriate method to engineer hollow TMP-rGO nanocomposites as effective materials for supercapacitors.

Facile synthesis of Fe-doped CoP nanosheet arrays wrapped by graphene for overall water splitting.

The development of durable, beneficial, and highly active non-precious metal-based electrocatalysts for hydrogen generation is a vital concern. This study proposes an effective strategy for the construction of Fe doped CoP nanosheet arrays wrapped by graphene (F0.25CP-G) on nickel foam as an efficient electrocatalyst for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). In this design, the final catalyst possesses a combination of the high conductivity of graphene, great surface porosity, and the intrinsic electrocatalytic activity of the F0.25CP-G which results in high-performance electrocatalytic activity toward the HER and OER. Therefore, the as-synthesized F0.25CP-G catalyst can achieve overpotentials of 66 mV and 230 mV for the HER and OER, respectively, in KOH at 10 mA cm-2. Furthermore, a practical electrolyzer (F0.25CP-G||F0.25CP-G) exhibits a current density of 10 mA cm-2 at 1.60 V along with good durability for 24 h.

Metal-organic-framework derived hollow manganese nickel selenide spheres confined with nanosheets on nickel foam for hybrid supercapacitors.

Metal-organic framework (MOF) derived nanoarchitectures have special features, such as high surface area (SA), abundant active sites, exclusive porous networks, and remarkable supercapacitive performance when compared to traditional nanoarchitectures. Herein, we propose a viable strategy for the synthesis of hollow manganese nickel selenide spheres comprising nanosheets supported on the nickel foam (denoted as MNSe@NF) from the MOF. The MNSe nanostructures can demonstrate enriched active sites, and shorten the ion-electron diffusion pathways. When the MNSe@NF electrode is used as a cathode electrode for a hybrid supercapacitor, the electrode reflected impressive supercapacitive properties with a high capacity of 325.6 mA h g-1 (1172.16 C g-1) at 2 A g-1, an exceptional rate performance of 86.6% at 60 A g-1, and remarkable longevity (3.2% capacity decline after 15 000 cycles). Also, the assembled MNSe@NF∥AC@NF hybrid supercapacitors employing activated carbon on the nickel foam (AC@NF, anode electrode) and MNSe@NF (cathode electrode) revealed an impressive energy density of 66.1 W h kg-1 at 858.45 W kg-1 and an excellent durability of 94.1% after 15 000 cycles.

A high-energy-density supercapacitor with multi-shelled nickel-manganese selenide hollow spheres as cathode and double-shell nickel-iron selenide hollow spheres as anode electrodes.

Thanks to the attractive structural characteristics and unique physicochemical properties, mixed metal selenides (MMSes) can be considered as encouraging electrode materials for energy storage devices. Herein, a straightforward and efficient approach is used to construct multi-shelled nickel-manganese selenide hollow spheres (MSNMSeHSs) as cathode and double-shell nickel-iron selenide hollow spheres (DSNFSeHSs) as anode electrode materials by tuning shell numbers for supercapacitors. The as-designed MSNMSeHS electrode can deliver a splendid capacity of ∼339.2 mA h g-1/1221.1 C g-1, impressive rate performances of 78.8%, and considerable longevity of 95.7%. The considerable performance is also observed for the DSNFSeHS electrode with a capacity of 258.4 mA h g-1/930.25 C g-1, rate performance of 75.5%, and longevity of 90.9%. An efficient asymmetric apparatus (MSNMSeHS||DSNFSeHS) fabricated by these two electrodes depicts the excellent electrochemical features (energy density of ≈112.6 W h kg-1 at 900.8 W kg-1) with desirable longevity of ≈94.4%.

A rational design of nanoporous Cu-Co-Ni-P nanotube arrays and CoFe2Se4 nanosheet arrays for flexible solid-state asymmetric devices.

Porous structures have attracted considerable attention as promising electrode designs for supercapacitor applications. Herein, we introduce a procedure towards the construction of nanoporous CuCoNi-P nanotube arrays (CCNP-NAs) by a metal-organic framework and hierarchical CoFe2Se4 nanosheet arrays (CFS-NAs) through a hydrothermal strategy, followed by selenization for the flexible asymmetric device. Due to the unique design of the electrode materials, the CCNP-NA and CFS-NA electrodes show exceptional specific capacities of ∼406.73 and 248.2 mA h g-1 at 2 A g-1, reasonable rate capabilities of 84.2 and 71.2% at 50 A g-1, and remarkable durability of 98.9% and 95.1%, respectively. Remarkably, an advanced flexible device was constructed using the CCNP-NA positive electrode and CFS-NA negative electrode. Our flexible device demonstrates tremendous energy density (∼153.5 W h kg-1 at 852.8 W kg-1), super-high durability of 96.2%, and considerable flexibility under bending conditions. This work proposes insight into the rational construction of porous nanostructures for next-generation electronic devices.

Boosting the energy density of supercapacitors by encapsulating a multi-shelled zinc-cobalt-selenide hollow nanosphere cathode and a yolk-double shell cobalt-iron-selenide hollow nanosphere anode in a graphene network.

The practical exploration of electrode materials with complex hollow structures is of considerable significance in energy storage applications. Mixed-metal selenides (MMSs) with favorable architectures emerge as new electrode materials for supercapacitor (SC) applications owing to their excellent conductivity. Herein, a facile and effective metal-organic framework (MOF)-derived strategy is introduced to encapsulate multi-shelled zinc-cobalt-selenide hollow nanosphere positive and yolk-double shell cobalt-iron-selenide hollow nanosphere negative electrode materials with controlled shell numbers in a graphene network (denoted as G/MSZCS-HS and G/YDSCFS-HS, respectively) for SC applications. Due to the considerable electrical conductivity and unique structures of both electrodes, the G/MSZCS-HS positive and G/YDSCFS-HS negative electrodes exhibit remarkable capacities (∼376.75 mA h g-1 and 293.1 mA h g-1, respectively, at 2 A g-1), superior rate performances (83.4% and 74%, respectively), and an excellent cyclability (96.8% and 92.9%, respectively). Furthermore, an asymmetric device (G/MSZCS-HS//G/YDSCFS-HS) has been fabricated with the ability to deliver an exceptional energy density (126.3 W h kg-1 at 902.15 W kg-1), high robustness of 91.7%, and a reasonable capacity of 140.3 mA h g-1.

Ultra-high energy density supercapacitors based on metal-organic framework derived yolk-shell Cu-Co-P hollow nanospheres and CuFeS2 nanosheet arrays.

Owing to the increased requirement for efficient energy storage systems (ESs), investigating favorable electrodes with porous nanoarchitecture for supercapacitors (SCs) is vital. Nonetheless, the development of these kinds of electrodes to obtain high energy density remains a difficult task. Low specific capacitances of positive (cathode) and negative (anode) electrode materials are a serious obstacle that limits the performance of asymmetric SCs (ASCs). Herein, we proposed the preparation of yolk-shell Cu-Co-P hollow nanospheres (Y-CCP HN) as a positive electrode using a metal-organic framework (MOF) and CuFeS2 nanosheet (CFS NS) arrays as a negative electrode via a low-cost and simple hydrothermal route for ASCs. The Y-CCP HN and CFS NS electrodes exhibited significant specific capacitances (∼2043.3 F g-1 (340.55 mA h g-1) and 654.3 F g-1 (218.1 mA h g-1), respectively), considerable rate performances (∼77.55% and 63.2%, respectively, even at 24 A g-1), and exceptional durability (96.7% and 95.3% after 8000 cycles, respectively). Most notably, the Y-CCP HN//CFS device delivers a wonderful energy density of 158.4 W h kg-1 at a power density of 900.3 W kg-1, a notable specific capacitance of 352.1 F g-1 (176.05 mA h g-1), and excellent cyclability (96.1% after 8000 cycles). This exploration demonstrates a good strategy for the construction of other metal phosphides and sulfides with porous nature, emphasizing considerable prospects for next-generation ESs.

Formation of graphene-wrapped multi-shelled NiGa2O4 hollow spheres and graphene-wrapped yolk-shell NiFe2O4 hollow spheres derived from metal-organic frameworks for high-performance hybrid supercapacitors.

To construct a supercapacitor (SC) with considerable performance, synthesis of an electrode material with a highly porous structure is necessary. Herein, an efficient metal-organic framework (MOF)-derived procedure is offered to construct a graphene wrapped multi-shelled NiGa2O4 hollow sphere (GW-MSNGOHS) positive electrode material and a graphene-wrapped yolk-shell NiFe2O4 hollow sphere (GW-YS-NFOHS) negative electrode material with a highly porous nature in SCs. The GW-MSNGOHS and GW-YS-NFOHS electrodes exhibit excellent capacities (∼411.25 mA h g-1 and 254.25 mA h g-1, respectively, at 1 A g-1), reasonable rate performances (75.85%, and 62.7%, respectively), and outstanding cyclability (98.9% and 90.9%, respectively). Benefiting from the reasonably engineered negative and positive electrodes, the fabricated asymmetric device (GW-MSNGOHS//GW-YS-NFOHS) can show an excellent energy density (ED) of 118.97 W h kg-1 at a power density (PD) of 1702 W kg-1, an exceptional robustness of 92.1%, and an excellent capacity (Cs) of 140.2 mA g-1.

Designing graphene-wrapped NiCo2Se4 microspheres with petal-like FeS2 toward flexible asymmetric all-solid-state supercapacitors.

Herein, we proposed a desirable strategy for the synthesis of graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (FeS2) (negative electrode) on nickel foam substrates. The positive electrode represents a substantial specific capacitance of 2112.30 F g-1 and excellent durability (6.8% loss after 5000 cycles). Furthermore, the negative electrode reflects good electrochemical performance with a specific capacitance of 321.30 F g-1 and a satisfactory rate capability of 47% capacitance retention. Considering the notable properties of the electrodes, a flexible asymmetric all-solid-state device based on graphene-wrapped NiCo2Se4 microspheres (positive electrode) and petal-like iron disulfide (negative electrode) was assembled. Our flexible device exhibits the high specific capacitance of 221.30 F g-1, the significant energy density of 78.68 W h kg-1 and excellent flexibility.