Emerging 2D Copper‐Based Materials for Energy Storage and Conversion: A Review and Perspective

Abstract

extensive interest, [1][2][3] such as SCs, [4] rechargeable ion batteries, [5] water splitting, [6] metal-air batteries, [7] and CO 2 RR. [8] However, the practical applications of SCs and rechargeable ion batteries are limited by low energy density and low power density, respectively. [9,10] The multiple-electron transfer reactions in water splitting have posed a significant challenge that limits the catalytic efficiency and cycle stability. [11] At present, the urgent issue of metal-air battery is to design high-performance bifunctional electrodes. [12] For CO 2 RR, the technical realization is limited by the activity and selectivity of the catalyst, and the selectivity of its product beyond that of CO. [13,14] In these electrochemical devices, electrodes represent the core component, which dictates the efficiency, energy and power density, as well as catalytic activity and durability.Since the birth of graphene, 2D materials have attracted great attention due to their unique electrochemical, mechanical, and optical properties and diverse applications, as manifested in over 3000 academic papers each year. [15,16] 2D materials possess some structural advantages over the 0D and 1D counterparts by interlayer gap bonding and weak out-of-plane Van der Waals interaction, which provides an interesting platform for energy storage and conversion research. [17,18] So far, the 2D material family mainly includes transition metal dichalcogenides, transition metal carbides, layered metal oxides, layered double hydroxides and other graphene-like materials, such as black phosphorus. Of these, copper-based materials have received extensive attention because of high natural abundance, low price, high strength, arc erosion resistance, easy preparation of various nanoshapes, wear resistance, etc. (Figure 1), [19,20] leading to excellent electrochemical performance and advancement of electrochemical energy storage and conversion (Figure 2). For example, with a large surface area and potential size effect, CuO nanostructures, a p-type semiconductor, have excellent physical and chemical properties for SCs, as well as interesting magnetic and superhydrophobic properties, as compared with other metal oxides, such as TiO 2 , ZnO, WO 3 , and SnO 2 . [21] Cu-S compounds are a promising lithium cathode with a high energy density and long cycling stability. [22] Cu-Se is also considered as a novel cathode 2D materials have shown great potential as electrode materials that determine the performance of a range of electrochemical energy technologies. Among these, 2D copper-based materials, such as Cu-O, Cu-S, Cu-Se, Cu-N, and Cu-P, have attracted tremendous research interest, because of the combination of remarkable properties, such as low cost, excellent chemical stability, facile fabrication, and significant electrochemical properties. Herein, the recent advances in the emerging 2D copper-based materials are summarized. A brief summary of the crystal structures and synthetic methods is started, and innovative strategies for improving electro...

Blending of a 3D cloud-like morphology with a 1D structure in a VO2/MXene nanocomposite to enhance the charge storage capability

“…The promising results as obtained by fabricating the symmetric 2-electrode supercapacitor system are in line with the reports highlighting the supercapacitor configuration. [73][74][75] This excellent supercapacitive behaviour as achieved could mainly be due to the promising morphology of the VO 2 /Mxene. Compared to the recent reports, [76][77][78][79][80] here straightaway vanadium-based nanomaterials (VO 2 nanowires) were employed probably for the first time as a precursor, which is supposed to catalyse the hydrothermal pressure in deforming MXene sheets and helps in the development of a promising nanocomposite with synergistically advanced surface properties.…”

Integrated battery–capacitor storage system: polyaniline interwoven Co-ZIF-derived hollow NiCo-LDH with enhanced electrochemical properties for hybrid supercapacitors

“…The use of MOFs as a supporting framework, by which metal ions and organic anions participate in the growth of the LDH, is a promising strategy to increase the electron transport rate and stability. [14][15][16] Wang et al used microwave technique to synthesize a 3D hollow NiCo-LDH with interleaved nanosheet shells using ZIF-67 as a template and employed it as an electrode material, revealing high specific capacity and satisfactory multiplier performance. 17 On the other hand, polyaniline (PANI) is a unique conductive polymer with a distinctive architecture and properties.…”

High energy density liquid state asymmetric supercapacitor devices using Co–Cr–Ni–Fe–Mn high entropy alloy

“…In addition, transition metal high entropy alloys (TMHEAs) have been one of the evolving electrode materials for supercapacitors, exhibiting promising capacitive performance. 15,16 Also, a few two-dimensional (2D) materials have been explored in the field of supercapacitors, 17 such as metalorganic frameworks, 18 nickel-based materials, 19 2D copperbased materials, 20 cobalt-nickel-tungsten nanosheets, 21 and 2D cobalt-based materials. 22,23 TMHEAs are formed by mixing various metallic elements and have specific physicochemical characteristics, such as outstanding magnetic and electrical properties, and high thermomechanical stability when the size is decreased to nanometer range.…”