Toward Rapid‐Charging Sodium‐Ion Batteries using Hybrid‐Phase Molybdenum Sulfide Selenide‐Based Anodes

Abstract

To attain both high energy density and power density in sodium‐ion (Na+) batteries, the reaction kinetics and structural stability of anodes should be improved by materials optimization. In this work, few‐layered molybdenum sulfide selenide (MoSSe) consisting of a mixture of 1T and 2H phases is designed to provide high ionic/electrical conductivities, low Na+ diffusion barrier, and stable Na+ storage. Reduced graphene oxide (rGO) is used as a conductive matrix to form 3D electron transfer paths. The resulting MoSSe@rGO anode exhibits high capacity and rate performance in both organic and solid‐state electrolytes. The ultrafast Na+ storage kinetics of the MoSSe@rGO anode is attributed to the surface‐dominant reaction process and broad Na+ channels. In situ and ex situ measurements are conducted to reveal the Na+ storage process in MoSSe@rGO. It is found that the MoS and MoSe bonds effectively limit the dissolution of the active materials. The favorable Na+ storage kinetics of the MoSSe@rGO electrode are ascribed to its low adsorption energy of −1.997 eV and low diffusion barrier of 0.087 eV. These results reveal that anion doping of metal sulfides is a feasible strategy to develop sodium‐ion batteries with high energy and power densities and long life‐span.

Porous graphene-like MoS2/carbon hierarchies for high-performance pseudocapacitive sodium storage

“…The initial CV curve for MoS 2 exhibits two identical initial redox peaks as that for MoS 2 /C100, but differently, MoS 2 only shows one sharp oxidation peak at ∼2.25 V. The MoS 2 /C50 electrode exhibits a similar trend to MoS 2 but with lower polarization due to the introduction of N,S-codoped C, which enhances the electrode conductivity. 18,59 In contrast, the MoS 2 /C150 electrode shows almost the same redox peaks as MoS 2 /C100. For comparison, CV curves of N-doped C are also provided in Fig.…”

“…Among various candidate anodes for SIBs, two-dimensional (2D) layered transition metal dichalcogenides have been widely investigated due to their weak van der Waals interaction forces, thus facilitating the insertion/extraction of Na + . 3,16–20 In this regard, molybdenum ( iv ) sulfide (MoS 2 ) has gained much attention because of its high theoretical capacity (670 mA h g −1 ) as well as large van der Waals gap (0.62 nm) along S–Mo–S layers. 16,21–24 However, low conductivity and severe volume variation lead to poor rate performance as well as rapid capacity fading upon cycling, therefore hindering its practical application in high energy/power density storage devices.…”

Molybdenum‐based materials for sodium‐ion batteries

“…Although the batteries based on liquid electrolytes have been extensively examined, solid‐state batteries feature higher energy density and safety 67,89 . In this regard, Chen et al designed molybdenum sulfide selenide (MoSSe) nanoribbons for solid‐state sodium batteries 90 . When tested in a Na 3 PS 4 electrolyte, MoSSe nanoribbons exhibited a high charge capacity of 523.1 mAh g −1 and Coulombic efficiency of 73.6% in the first cycle.…”

In Situ Growth of CoSe2 Coated in Porous Carbon Layers as Anode for Efficient Sodium‐Ion Batteries

“…In recent years, sodium-ion batteries (SIBs) have attracted great attention due to low costs and abundant sodium material resources, [1][2][3] which was regarded as promising alternatives to Li-ion batteries (LIBs). [4] Unfortunately, the radius of Na þ ion is more than 1.34 times that of Li þ ion, which leads to the sluggish reaction dynamics and large volume changes during the Na þ insertion/extraction process.…”