Novel Amorphous MoS₂/MoO₃/Nitrogen-Doped Carbon Composite with Excellent Electrochemical Performance for Lithium Ion Batteries and Sodium Ion Batteries

A novel amorphous MoS₂/MoO₃/nitrogen-doped carbon composite has been successfully synthesized for the first time. The synthesis strategy only involves a facile reaction that partially sulfurizes organic–inorganic hybrid material Mo₃O₁₀ (C₂H₁₀N₂) (named as MoO_<i>x</i>/ethylene­diamine) nanowire precursors at low temperature (300 °C). It is more interesting that such amorphous composites as lithium ion battery (LIB) and sodium ion battery (SIB) anode electrodes showed much better electrochemical properties than those of most previously reported molybdenum-based materials with crystal structure. For example, the amorphous composite electrode for LIBs can reach up to 1253.3 mA h g^–1 at a current density of 100 mA g^–1 after 50 cycles and still retain 887.5 mA h g^–1 at 1000 mA g^–1 after 350 cycles. Similarly, for SIBs, it also retains 538.7 mA h g^–1 after 200 cycles at 300 mA g^–1 and maintains 339.9 mA h g^–1 at 1000 mA g^–1 after 220 cycles, corresponding to a capacity retention of nearly 100%. In addition, the amorphous composite electrode exhibits superior rate performance for LIBs and SIBs. Such superior electrochemical performance may be attributed to the following: (1) The carbonaceous matrix can enhance the conductivity of the amorphous composite. (2) Heteroatom, such as N, doping within this unique compositional feature can increase the active ion absorption sites on the amorphous composite surface benefitting the insertion/extraction of lithium/sodium ions. (3) The hybrid nanomaterials could provide plenty of diffusion channels for ions during the insertion/extraction process. (4) The 1D chain structure reduces the transfer distance of lithium/sodium ions into/from the electrode

Yolk–Shell Sn@C Eggette-like Nanostructure: Application in Lithium-Ion and Sodium-Ion Batteries

Yolk–shell carbon encapsulated tin (Sn@C) eggette-like compounds (SCE) have been synthesized by a facile method. The SCE structures consist of tin cores covered by carbon membrane networks with extra voids between the carbon shell and tin cores. The novel nanoarchitectures exhibit high electrochemical performance in both lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). As anodes for LIBs, the SCE electrodes exhibit a specific capacity of ∼850 mA h g^–1 at 0.1 C (100 mA g^–1) and high rate capability (∼450 mA h g^–1 remains) at high current densities up to 5 C (5000 mA g^–1). For SIBs, the SCE electrodes show a specific capacity of ∼400 mA h g^–1 at 0.1 C and high rate capacity (∼150 mA h g^–1 remains) at high current densities up to 5 C (5000 mA g^–1)