Ultrathin MoS₂ nanosheets homogenously embedded in a N,O-codoped carbon matrix for high-performance lithium and sodium storage

Abstract

Ultrathin MoS2 nanosheets uniformly embedded into a N,O-codoped carbon matrix possess outstanding cyclability and rate performances as a lithium/sodium ion battery anode.

Pressure‐Induced Vapor Synthesis of Carbon‐Encapsulated SiOx/C Composite Spheres with Optimized Composition for Long‐Life, High‐Rate, and High‐Areal‐Capacity Lithium‐Ion Battery Anodes

“…)/metal alloys, metal oxides (SnO x , TiO 2 , etc. ), and metal sulfides (MoS 2 ) . For these candidate materials, SiO x is attractive because it exhibits better stability than pure Si.…”

Pressure‐Induced Synthesis of Homogeneously Dispersed Sn/SnO2/C Nanocomposites as Advanced Anodes for Lithium‐Ion Batteries

“…However, C 2 H 6 OSn only contains a SnO bond and two SnC bonds. When SnC bonds are broken, only two methyl groups are formed, which cannot form carbon spheres alone, but can form a uniformly dispersed structure with SnO bonds under the elevated pressure …”

“…Sample‐IV shows the E g and A 1g vibration modes of SnO, and A 1g vibration modes of SnO 2 at low wavenumber region, again suggesting that the formation of SnO and SnO 2 . In the Raman spectra, intensity ratios of D and G peaks ( I D / I G ratios) indicate the degree of disorder of the graphitic structure . Higher I D / I G ratios indicate more defects in the carbon, resulting in poorer crystallinity of carbon.…”

“…It can be seen that the I D / I G ratio decreases with the increase in synthesis temperature, indicating that defects decrease and crystallinity increases for carbon with increasing temperature. Defects can accommodate Li + , which is favorable for lowering the volume expansion, thus improving cyclability and capacity of active materials . In addition, sample‐II and sample‐IV possess the same synthesis temperature; however, sample‐II has higher I D / I G ratio than that of sample‐IV, indicating that the increased pressure in the sealed vessel can increase the defects, thus decreasing the crystallinity of carbon matrix.…”

“…Both results show that sample‐II has the highest carbon content (14.5 wt%) and higher oxygen content (11.1 wt%). At 400 °C, C 2 H 6 OSn has totally decomposed (Figure S4, Supporting Information), which can release a large amount of gaseous substances in the sealed vessel, thus producing the elevated pressure . At this moment, due to low reaction temperature, the pressure produced by the decomposition of C 2 H 6 OSn is not enough to make carbon‐containing gaseous substance completely converted into solid carbon.…”