Construction of Interlayer-Expanded MoSe₂/Nitrogen-Doped Graphene Heterojunctions for Ultra-Long-Cycling Rechargeable Aluminum Storage

Abstract

Owing to their low cost and abundant reserves, aluminum-ion batteries (AIBs) have been considered a potential candidate for future large-scale storage applications. However, AIBs are still in the stage of intensive research due to their cathodes of limited specific capacity, energy density, and cycling stability. In this work, interlayer-expanded MoSe2/nitrogen-doped graphene (MoSe2/N-G) heterojunctions with fewer layers and fine dispersion are synthesized by a facile hydrothermal method. Experimental verification and theoretical calculation reveal that the unique heterojunction structure and hetero-element doped graphene conductive network are beneficial for improving the electrochemical reaction kinetics and provide more active vacancies for AIBs, as well as slow the structural degradation during the discharge/charge process. When serving as a cathode material for AIBs, the as-prepared MoSe2/N-G electrode presents a high specific capacity of 167 mAh g–1 at 0.2 A g–1. Meanwhile, the hybrid also exhibits excellent cycling stability (140 mAh g–1 at 0.2 A g–1 after 1000 cycles) with a high Coulombic efficiency of 99.54% and less than 16% loss of discharge capacity. As verified by ex situ X-ray photoelectron spectroscopy (XPS)/transmission electron microscopy (TEM) characterization and first-principles calculations, the Al3+ intercalation mechanism of the MoSe2/N-G electrode in AIBs are further confirmed.

Design Strategies of High‐Performance Positive Materials for Nonaqueous Rechargeable Aluminum Batteries: From Crystal Control to Battery Configuration

“…Similarly, the designed MoSe 2 /N-doped graphene composite exhibited the expanded interlayer spacing (from 0.63 nm of bulk MoSe 2 to 0.67 nm), which could improve the ion diffusion rate during the discharge/charge process. [134] In conclusion, interlayer spacing enlarging strategy has been demonstrated as an effective way to adjust the structure with the optimization of interlayer spacing, realizing the improved diffusivity/reaction kinetics and enhanced electrochemical performance. However, we notice that the interlayer spacing is rarely accurately regulated in previous reports.…”

Cation-intercalation and conversion-type cathode materials for rechargeable aluminum batteries

“…MoSe 2 was also investigated as the cathode for RABs by An and coworkers. 23 High-resolution transmission electron microscopy (HRTEM) analysis indicated that the d-spacing of MoSe 2 was increased from 6.7 Å to 7.2 Å after full discharge, and it returned to the original state after charging (Fig. 3g).…”

“…Theoretical calculations indicated that it would be extremely difficult if not impossible for Al 3+ to intercalate in transition metal oxides or sulfides. 7 Nevertheless, transition metal oxides, [8][9][10][11][12][13] chalcogenides, [14][15][16][17][18] and their carbon-based composites [19][20][21][22][23][24] have been reported as Al 3+ intercalation cathode materials. It must be pointed out that Al 3+ intercalation in the current chloroaluminate ionic liquid electrolytes involves chloroaluminate anions, since there are no simple Al 3+ cations existing in these electrolytes.…”

“…Overall, the layered TiS 2 cathode demonstrated a higher reversible capacity than the cubic spinel Cu 0.31 Ti 2 S 4 , indicating that the 2D layered structure may be preferable for Al 3+ intercalation. To date, a number of other 2D transition metal dichalcogenides including vanadium disulfide (VS 2 ), 20 molybdenum disulfide (MoS 2 ) 21 and molybdenum diselenide (MoSe 2 ) 23 have been reported as cathodes of RABs. Wu et al reported a nanosheet VS 2 -graphene composite that exhibited a reduction peak at 0.45 V and an oxidation peak at 1.6 V versus Al in CV as displayed in Fig.…”

Nanobelts-constructed Porous TiO2-B@SnS2 Heterostructure Hybrids for Enhance Lithium Storage Performance

“…So far, simple single-phase electrode materials are not enough to satisfy the requirement for reversible capacity and cycling stability [11] . Many researchers have done a lot of research on the composite and structural design of electrode materials, such as carbon coating [13][14][15] , heterostructure construction [1] and defective construction [16] , et al Conclusion, heterostructure construction has been proved to be an effective technical tool to improve the charge and electronic transfer kinetics and suppress the volume change during the electrochemical reaction process [17,18] . Mai et al [19] designed WS 2 /ZnS heterojunctions that shows enhance ions and electronic diffusion kinetics.…”