3D Binder-free Electrode Research Articles

Flexible three-dimensional-networked iron vanadate nanosheet arrays/carbon cloths as high-performance cathodes for magnesium ion batteries

Owing to their safety and low cost, magnesium ion batteries (MIBs) have attracted much attention in recent years. However, the sluggish diffusion dynamics of magnesium ions hampers the search for appropriate cathode materials with excellent electrochemical performance. Herein, we design and synthesize a novel flexible three-dimensional-networked composite of iron vanadate nanosheet arrays/carbon cloths (3D FeVO/CC) as a binder-free cathode for MIBs. Relative to bare FeVO nanosheets, the 3D binder-free electrode with designed architecture enables a full range of electrochemical potential, including a high specific capacity of 270 mA h g−1 and an increased life span (over 5000 cycles). Such achievable high-density energy originates from the synergistic optimization of electron and ion kinetics, while the durability benefits from the robust structure that prevents degradation in cycling. The single-phase reaction mechanism of FeVO in the magnesium ion storage process is also explored by in-situ X-ray diffraction and Raman technologies. Moreover, a flexible MIB pouch cell (3D FeVO/CC|MgNaTi3O7) is assembled and exhibits practical application potential. This work verifies that 3D FeVO/CC is a potential candidate cathode material that can satisfy the requirements of high-performance MIBs. It also opens a new avenue to improve the electrochemical performance of cathode materials for MIBs.

One-step preparation of 3D binder-free electrode of porous Co-Mo-S nanostructures grown on Ni foam for supercapacitors

Transition metal chalcogenides have wide studied as active electrode materials for electrochemical storage devices. In this study, we successfully fabricated a binder-free electrode of hierarchical Co-Mo-S nanosheets on nickel foam (CMS/NF) by a facile hydrothermal method under microwave irradiation. The CMS layer, with a thickness of a few nanometers, was decorated on the NF's surface. Taking advantage of the large specific surface area of NF and the high capacitance and porosity of CMS, the prepared electrode is believed to have a rapid electron and ion transport, large electroactive sites, and excellent cycle stability. The specific capacitance of 1080 F g−1 at 1 A g−1 and excellent cycling stability (90.4% retention in specific capacitance after 5000 cycles) were obtained. For further practical applications, an asymmetric supercapacitor was assembled using the CMS/NF as the cathode and the activated carbon as anode material. The prepared device exhibited a high capacitance of 47 F g−1 at 1 A g−1 and a high energy density of 42.6 Wh kg−1 at a power density of 850.3 W kg−1 at a wide operating voltage of 1.6 V. This current method could provide a rapid one-step process for other 3D porous electrodes for high-performance supercapacitors.

Fabrication of 3D binder-free graphene NiO electrode for highly stable supercapattery

Electrochemical stability of energy storage devices is one of their major concerns. Polymeric binders are generally used to enhance the stability of the electrode, but the electrochemical performance of the device is compromised due to the poor conductivity of the binders. Herein, 3D binder-free electrode based on nickel oxide deposited on graphene (G-NiO) was fabricated by a simple two-step method. First, graphene was deposited on nickel foam via atmospheric pressure chemical vapour deposition followed by electrodeposition of NiO. The structural and morphological analyses of the fabricated G-NiO electrode were conducted through Raman spectroscopy, X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray spectroscopy (EDS). XRD and Raman results confirmed the successful growth of high-quality graphene on nickel foam. FESEM images revealed the sheet and urchin-like morphology of the graphene and NiO, respectively. The electrochemical performance of the fabricated electrode was evaluated through cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), and electrochemical impedance spectroscopy (EIS) in aqueous solution at room temperature. The G-NiO binder-free electrode exhibited a specific capacity of ≈ 243 C g−1 at 3 mV s−1 in a three-electrode cell. A two-electrode configuration of G-NiO//activated charcoal was fabricated to form a hybrid device (supercapattery) that operated in a stable potential window of 1.4 V. The energy density and power density of the asymmetric device measured at a current density of 0.2 A g−1 were estimated to be 47.3 W h kg−1 and 140 W kg−1, respectively. Additionally, the fabricated supercapattery showed high cyclic stability with 98.7% retention of specific capacity after 5,000 cycles. Thus, the proposed fabrication technique is highly suitable for large scale production of highly stable and binder-free electrodes for electrochemical energy storage devices.

Hierarchical CuO@ZnCo–OH core-shell heterostructure on copper foam as three-dimensional binder-free electrodes for high performance asymmetric supercapacitors

Rational architecture design and ingenious electrochemical performance optimization are highly desirable in developing high-performance asymmetric supercapacitors. Herein, a facile electrodeposition strategy is adopted to construct the hierarchical core-shell architecture of binary transitional metal hydroxide nanosheets anchored on copper foam ( CF) supported three-dimensional (3D) CuO scaffolds. The synergistic contributions from different electro-active components are maximized by the heterostructures construction and components optimization. As a result, the 3D binder-free electrode of CF supported CuO@Zn1Co2-OH core-shell heterostructure achieve a high areal capacitance of 2.634 F cm−2 at 5 mA cm−2, enhanced rate performance (71.6% retention at 30 mA cm−2), and long durability (99.1% after 4000 cycles). Additionally, a CuO@Zn1Co2–OH//LSDC (loofah sponge derived carbon) asymmetric supercapacitor (ASC) is assembled with an operating voltage of 1.5 V. The ASC device delivers a maximum energy density of 0.21 mW h cm−2 (22.10 W h kg−1) at a power density of 4.08 mW cm−2 (434 W kg−1), and exceptional cycling stability (91.7% of capacitance retention after 4000 cycles). Of practical importance, this work broadens our horizons in fabricating novel hierarchical core-shell heterostructures for next-generation electrochemical energy-storage technologies.

Construction of ZnCo2O4 nanowire arrays 3D binder-free electrode with highly catalytic activity towards glucose oxidation

Direct growth of binary metal oxide nanoarray catalyst on 3D conductive substrate offers electrode materials with high conductivity and large specific surface area, representing an effective strategy to boost the performance of electrocatalyst. In the paper, we report the construction of ZnCo2O4 nanowire arrays supported on carbon cloth (ZnCo2O4 NWAs/CC) and its application for enzyme-free glucose oxidation. ZnCo2O4 NWAs/CC was prepared via a simple hydrothermal synthesis with subsequent calcination process. As an 3D self-supported enzyme-free electrode for glucose sensing, ZnCo2O4 NWAs/CC exhibited excellent catalytic activity with a high sensitivity of 3.88 ​mA ​mM-1 ​cm-2, a wide linear range from 5 ​μM to 0.5 ​mM, and a low detection limit of 2.5 ​μM ​(S/N ​= ​3). Moreover, the proposed sensor shows high selectivity and good reliability for real sample analysis.

Three-Dimensional Honeycomb-Structural LiAlO2-Modified LiMnPO4 Composite with Superior High Rate Capability as Li-Ion Battery Cathodes

In the efforts toward the rapidly increasing demands for high-power application, cathode materials with three-dimensional (3D) architectures have been proposed. Here, we report the construction of the 3D LiAlO2-LiMnPO4/C cathode materials for lithium-ion batteries in an innovation way. The as-prepared 3D active materials LiMnPO4/C and the honeycomb-like Li-ion conductor LiAlO2 framework are used as working electrode directly without additional usage of polymeric binder. The electrochemical performance has been improved significantly due to the special designed core-shell architectures of LiMnPO4/C@LiAlO2. The 3D binder-free electrode exhibits high rate capability as well as superior cycling stability with a capability of ∼105 mAh g-1 and 98.4% capacity retention after 100 cycles at a high discharge rate of 10 C. Such synthesis method adopted in our work can be further extended to other promising candidates and would also inspire new avenues of development of 3D materials for lithium-ion batteries.

CuCo2O4nanowire arrays supported on carbon cloth as an efficient 3D binder-free electrode for non-enzymatic glucose sensing

CuCo2O4nanowire arrays supported on carbon cloth (CuCo2O4NWAs/CC) were preparedviaa simple hydrothermal synthesis and subsequent calcination process and utilized as a 3D binder-free electrode for non-enzymatic glucose sensing with high performance.

Hierarchical Co(OH)2nanotube arrays grown on carbon cloth for use in non-enzymatic glucose sensing

Hierarchical Co(OH)2nanotube arrays grown on carbon cloth (Co(OH)2NTAs/CC) were prepared and utilized as a 3D binder-free electrode for non-enzymatic glucose sensing with high efficiency.

3D Binder-free MoSe2 Nanosheets/Carbon Cloth Electrodes for Efficient and Stable Hydrogen Evolution Prepared by Simple Electrophoresis Deposition Strategy

We successfully developed a simple electrophoretic deposition (EPD) method to decorate the MoSe2 nanosheets on the carbon fiber surface of carbon cloth (MoSe2/CC). With this process, MoSe2 nanosheets can be uniformly and tightly deposited on this flexible conductor to form a 3D binder-free electrode for hydrogen evolution reaction (HER). The film thickness can also be controlled by the EPD time. Directly used as binder-free electrodes for hydrogen evolution reaction, the as-prepared 3D MoSe2/CC samples exhibit excellent catalytic activity in an acidic electrolyte (21 mA/cm2 at an over-potential of 250 mV). Variation of MoSe2 nanosheets film thickness in the electrodes could affect the catalytic activity, and it was found that the MoSe2/CC sample prepared with 60 min EPD time shows the highest HER activity amongst these different thickness samples. Moreover, stability tests though long-term potential cycles (no degradation after 1000 continuous potential cycles) and extended electrolysis confirm the exceptional durability of the catalyst. This development offers us an attractive and active 3D electrode for electrochemical water splitting.

Multi-channeled hierarchical porous carbon incorporated Co3O4 nanopillar arrays as 3D binder-free electrode for high performance supercapacitors

3D hierarchical carbon-based nanostructures not only create hierarchical porous channels, but also possess high electrical conductivity and maintain excellent structural mechanical stability for high-performance supercapacitors. In this research, hierarchical porous N-doped carbon and Co3O4 nanopillar arrays derived from Morpho butterfly wing scales have been explored. These structures have demonstrated enhanced capacitance, with a maximum specific capacity of 978.9Fg−1 at 0.5Ag−1, and good cycling stability, retaining about 94.5% of their capacitance after 2000 cycles as well as improving supercapacitor energy density without sacrificing power density. The maximum energy density of the carbonized wing scale-cobalt oxide (CWs-Co3O4) composite supercapacitors was found to be 99.11Whkg−1. This paper proposes a method for building 3D hierarchical N-doped carbon materials with various morphologies. It also presents a concept and method for designing a carbon-based 3D binder-free electrode with a hierarchical structure. This research provides a vast structural pool for developing novel electrochemical properties based on these materials.