Synthesis of Grain‐like MoS₂ for High‐Performance Sodium‐Ion Batteries

Abstract

MoS is a promising anode material for sodium-ion batteries (SIBs) due to its attractive theoretical capacity and low cost. MoS generally presents a sheet-like structure based on its (002) lattice plane; however, such a structure tends to result in agglomeration and stacking of the sheets that cannot accommodate volume expansion, resulting in poor cyclability. Herein, grain-like MoS particulates (G-MoS ) are synthesized by sulfiding MoO in highly concentrated sulfur vapor, which results in epitaxial growth of MoS in (002), (100), and (110) lattice planes, with the product consisting of MoS particulates of about 300 nm coated with few-layered MoS nanosheets. The unique G-MoS architecture ensures good dispersion and sufficient distance to accommodate volume expansion during sodiation/desodiation, which effectively prevents stacking of MoS , maintaining structural stability. When employed as the working electrode for SIB, G-MoS delivers a high reversible capacity of 324 mAh g at 0.5 A g , retaining 312 mAh g over 300 cycles with an average coulombic efficiency of 99.8 %. Even when G-MoS is cycled at a high current density (2.0 A g ), the retained capacity is 175 mAh g after 400 cycles. Comparison with literature reveals that these capacities are among the more promising reversible values reported for pure MoS .

Na2Ti3O7/C Nanofibers for High‐Rate and Ultralong‐Life Anodes in Sodium‐Ion Batteries

“…Preservation of the structure after cycled is an important embodiment of the electrochemical stability of electrode materials . In order to prove the causes of the outstanding electrochemical performance of Na 2 Ti 3 O 7 /C FNFs electrode, the Na half‐cell tested at the current density of 1 C (1 C=177 mA h g −1 ) for 100 cycles was disassembled, and the morphology and microstructure of after‐cycled Na 2 Ti 3 O 7 /C FNFs electrode were observed by TEM.…”

Bundled Defect‐Rich MoS2 for a High‐Rate and Long‐Life Sodium‐Ion Battery: Achieving 3D Diffusion of Sodium Ion by Vacancies to Improve Kinetics

“…The MoO 3 plays a role in bundling MoS 2 . When tested as an electrode, such an architecture with a decreased surface energy reduces the stack of sheets enabling a long cycle life . A typical edge view of MoS 2 with clear lattice fringes is measured to be 0.64 nm assigned to (002) plane of 2H‐MoS 2 .…”

“…The BD‐MoS 2 electrode maintains an integrated structure after cycling, enabling a long cycle life (Figure S9, Supporting Information) . It can deliver a capacity of 354 mAh g −1 at 0.5 A g −1 after 100 cycles with an average coulombic efficiency (CE) of 98.5% (Figure b).…”

“…The lower slope of σ w suggests a better Na + storage kinetics in BD‐MoS 2 electrode based on the diffusion formula (Figure S15, Supporting Information). After 100 cycles, the BD‐MoS 2 electrode still has a smaller impedance, while the impedance of the as‐prepared MoS 2 electrode significantly increases due to destroyed diffusion path of Na + (Figure S15c,d, Supporting Information) …”

Defect Control in the Synthesis of 2 D MoS2 Nanosheets: Polysulfide Trapping in Composite Sulfur Cathodes for Li–S Batteries

“…MoS 2 is a 2 D material of increasing research interest recently owing to its interesting physical and electronic properties, including high conductivity, high surface area, and active sites for a diversity of applications . Previous reports relevant to Li–S batteries have used MoS 2 as a means to inhibit or anchor PS species during electrochemical cycling .…”