Near-Atomic-Thick Bismuthene Oxide Microsheets for Flexible Aqueous Anodes: Boosted Performance upon 3D → 2D Transition

Abstract

Aqueous batteries provide safety, but they usually suffer from low energy and short lifetimes, limiting their use for large-scale energy storage. Two-dimensional materials with infinite lateral dimensions have inherent properties such as high surface area and remarkable power density and cycling stability that are shown to be critical for the next generation of energy storage systems. Here, ultrathin bismuthene oxide with a large aspect ratio is studied as an anode material for rechargeable aqueous metal-ion batteries. The metal oxides are prepared via a novel electrochemical system allowing for a smooth, high-quality transition of bismuthene to bismuthene oxide in a short time. This anodic system is shown to overcome major limiting factors of such batteries, including low capacity and irreversible and unstable redox reactions in aqueous electrolytes. The essential energy storage properties of two-dimensional (2D) microsheets, without the addition of conductive additives and binders, are compared with those of the corresponding three-dimensional (3D) structures. Notably, the battery performance of 2D microsheets is significantly better than that of nanoparticles from all examined aspects, including power density and potential and cycling stability, while exhibiting a capacity density close to their theoretical value. Moreover, 2D microsheets have shown impressive mechanical flexibility related to the ultrathin thickness of individual microsheets and strong interaction between them after film deposition. Combining the excellent energy storage properties of bismuthene oxide, the simple electrode preparation procedure, the inherent flexing characteristic, and the nontoxicity of both the battery material and the electrolyte makes this 2D material an exceptional candidate for large-scale wearable green electronics.

Sonochemical Synthesis of Large Two‐Dimensional Bi2O2CO3 Nanosheets for Hydrogen Evolution in Photocatalytic Water Splitting

“…Comparing to prior literature, the observation of 2D Bi 2 O 2 CO 3 is surprising: Recent work by Pumera et al [13,51] found for a similar sonication scheme to ours and also in water, not 2D Bi 2 O 2 CO 3 but large metallic β-Bi nanosheets to be produced while MeOH resulted in small metallic β-Bi(001) nanoflakes. In fact, Pumera et al explicitly excluded bismuth oxidation in their study.…”

“…Pumera et al suggested for their 60 min sonications result in H 2 O not only physical exfoliation of the parent Bi powder to take place but due to Bi's low melting point (≈271 °C), Bi melting under the tip sonicator, dissolution effects, and then crystallite growth in suspension to partake in large nanosheet formation. [13,51] In contrast, in MeOH for 60 min, Pumera et al suggested fragmentation (rather than crystallite growth as in H 2 O) to be the dominant mechanism for small nanoflake formation. While Pumera et al's maximum 60 min processing times resulted in metallic β-Bi nano-sheets/-flakes, we suggest that for our much longer 15 h processing, in addition to the crystallite growth/fragmentation mechanisms suggested by Pumera et al also concurrent oxidation and carbonate bridging/intercalation processes of the Bi in H 2 O and MeOH take place.…”

The Metallocene Battery: Ultrafast Electron Transfer Self Exchange Rate Accompanied by a Harmonic Height Breathing

“…Height change of anode or cathode materials in a closed battery cell creates internal pressure, generally, leading to the fast degradation of electrode materials and thus, low cyclability. [16] We have addressed this issue by combining a PCo@rGO anode with a PFc@rGO cathode in a full Co-Fe metallocene battery. In such a configuration, the individual height changes of the two electrode materials are reciprocal and add up formally to zero total electrolyte volume change and thereby prohibiting internal pressure build-up during cycling.…”

Two-Dimensional Layered Bismuthene/Antimonene Nanocomposite as a Potential Electrode Material for the Fabrication of High-Energy Density Hybrid Supercapacitors

“…Inspired by the development of two-dimensional (2D) graphene and its fascinating properties, the other 2D materials such as transition metal dichalcogenides/trichalcogenides, layered double hydroxides, MXenes, hexagonal boron nitride (h-BN), metal organic frameworks, metallenes, and so on have been widely studied in a diverse field of next-generation applications like ultrafast photonics, spintronics, and advanced nanogenerators, microfluidic constructions for flexible electronics, and so on. − Moreover, intensive efforts have been devoted to utilizing these 2D materials in energy storage and harvesting applications because of their exceptional physical, chemical, and electronic properties like a tunable bandgap, large surface area, high electrical conductivity, desirable pore volumes, adjustable interlayers, and other adaptable functionalities. − In particular, atomically thin 2D mono-selemental metallenes such as phosphorene, antimonene, silicene, and so on have attracted researchers for batteries, supercapacitors, and other energy storage applications because of their outstanding electrochemical properties owing to the complete exposure of surface molecules, intercalation of ions between the van der Waals interlayers, and the edge atoms and basal planes of nanosheets provide more active functional groups. − Nowadays, researchers focus on the synthesis and fabrication of advanced 2D materials and explore them in a diverse field of applications. Bismuthene is a 2D allotrope of bismuth that possesses structural similarity with that of graphite, and it is nontoxic, cost-effective, and eco-friendly with an outstanding volumetric capacity of about 3765 mAh/cm 3 , high electronic conductivity, high carrier mobility, and good air stability making it an ideal candidate for electrochemical supercapacitors. − Recently, the development of novel ultrathin 2D bismuthene has spiked interest in lithium-ion and sodium-ion batteries owing to their large interlayer spacing of 3.979 Å along the c -axis, favoring the diffusion of both lithium ions and sodium ions with ionic radii of 1.52 and 2.04 Å between the interlayers. However, the investigation of 2D bismuthene in supercapacitors is extremely scarce comparable with other mono-elemental metallenes. , Similarly, the allotropes of antimonene (α, β phases) are found to be an energetically stable 2D material providing outstanding carrier mobility, rapid ion transfer kinetics, highly structural stability, and superior electrical conductivity of about 1.6 × 10 4 S/cm owing to its highly stable spin-orbit coupling. , Antimonene has been used in a diverse field of applications like ultraviolet nano-optical applications, lithium-sulfur batteries, and supercapacitors. − Emiliano Martínez-Periñán et al reported the novel 2D antimonene for supercapacitor applications, providing an ultrahigh specific capacitance of 1578 F/g at a high current density of about 14 A/g.…”