Covalent Pinning of Highly Dispersed Ultrathin Metallic-Phase Molybdenum Disulfide Nanosheets on the Inner Surface of Mesoporous Carbon Spheres for Durable and Rapid Sodium Storage

Abstract

Two-dimensional (2D) transition-metal dichalcogenide materials show potential for use in alkali metal ion batteries owing to their remarkable physical and chemical properties. Nevertheless, the electrochemical energy storage performance is still impaired by the tendency of aggregation, volume, and morphological change during the conversion reaction and poor intrinsic conductivity. Until now, ultrathin molybdenum disulfide nanosheets with a metallic-phase structure on the inner surface of mesoporous hollow carbon spheres (M-MoS2@HCS) have rarely been investigated as an anode for sodium-ion batteries. In this work, a novel M-MoS2@HCS anode was designed and synthesized by employing a template-assisted solvothermal reaction. Structural and chemical analyses indicate that the M-MoS2 nanosheets with a larger interlayer spacing compared to their semiconductor counterpart grow on the inner surface of HCS via covalent interactions. When used as the anode materials for Na+ storage, the M-MoS2@HCS anode presents durable and rapid sodium storage properties. The developed electrode shows a reversible capacity of 291.2 mAh g–1 at a high current density of 5 A g–1. After 100 cycles at 0.1 A g–1, the reversible capacity is 401.3 mAh g–1 with a capacity retention rate of 79%. After 2500 cycles at 1.0 A g–1, the electrode still delivers a reversible capacity of 320.1 mAh g–1 with a capacity retention rate of 75%. The excellent sodium storage capability of the MoS2@HCS electrode is explained by the special structural design, which reveals great potential to accelerate the practical applications of transition-metal dichalcogenide electrodes for sodium storage.

Conductive Co-based metal organic framework nanostructures for excellent potassium- and lithium-ion storage: kinetics and mechanism studies

“…where a and b are constants, and the b value can be used to judge the ion storage mechanism, either controlled by diffusion (b ¼ 0.5) or by pseudocapacitance (b ¼ 1.0). 64,65 From Fig. 5B, the tted b value using the oxidation peak is 0.89, indicating that the potassiation/depotassiation process is mainly controlled by the pseudocapacitance process.…”

Cotton textile inspires MoS2@reduced graphene oxide anodes towards high-rate capability or long-cycle stability sodium/lithium-ion batteries

“…Nevertheless, for CC/MoS 2 @RGO-700, the distinct peak at 13.5°is replaced by the (002) and (004) planes at 9°and 18°, respectively, suggesting the formation of 1T-MoS 2 with expanded interlayer spacing, in agreement with TEM observation. 19,20 In the subsequent parts, the optimum compositions with the addition of 150 mg Na 2 MoO 4 •2H 2 O are selected for further investigation, and they are designated as PCC/MoS 2 , CC/MoS 2 , and CC/MoS 2 @RGO-X (X represents the combustion temperature) for short.…”

Rational design and regulation of tremella-like selenium-doped MoS2 for highly reversible sodium storage

“…25 Aer the addition of Se atoms, the Raman spectra exhibit characteristic peaks at 143 and 278 cm −1 corresponding to the J 2 and E 1 2g (Mo-Se) vibrations of 1T MoSe 2 ; the 1T/2H hybrid phase is favorable for low conversion energy and fast electron transfer. 26 Subsequently, the prominent peaks at 1360 cm −1 (D band) and 1589 cm −1 (G band) of carbon appear aer carbon coating; these peaks correspond to disordered carbon from graphitic sp 3 -hybridization and graphic carbon from the E 2g vibratory mode, respectively 27 (Fig. S6c †).…”

“…2 Likewise, the critical issue with SIBs is that the larger ion radius (Na + : 1.06 Å vs. Li + : 0.76 Å) leads to more sluggish transport kinetics and a large volume change, yielding reduced capacity and poor rate performance, while the low power density limits its practical application. 3 In parallel, the electrode material determines the energy density, cycle life and safety of SIBs in practical application. 4,5 Therefore, it is urgent to nd suitable anodes with high sodium storage energy density and rate capacity.…”