Superior electrochemical performance of MoS2 decorated on functionalized carbon nanotubes as anode material for sodium ion battery

Abstract

A simple one-pot hydrothermal process has been used for synthesis of MoS2/C/CNT composite for anode material of sodium ion battery. The Mo7O246- anion from (NH4)6Mo7O24 gets attached on functionalized CNT at lower pH as the later shows positive zeta potential at that pH. Just by simultaneous addition of carbon and 10% CNT to MoS2, the capacity improves from 298 mAh/g to 559 mAh/g at 50 mA/g current density. The cycle life also shows excellent improvement from 30 cycles in case of MoS2 to 150 cycles for CNT decorated composite. Cyclic voltammetry, XANES and XRD have been performed to understand intercalation mechanism which suggest that initially sodiated MoS2 forms which subsequently breaks down into Na2S and Mo. Superior performance of MoS2/C/CNT composite was due to its least charge transfer resistance. CNT present in the composite provides high electronic conductivity, mechanical strength and also entrap the polysulphides forms during cycling. A full cell fabricated using Na(Ni0.5Mn0.3Co0.2)O2 and MoS2/C/CNT as positive and negative electrodes, respectively, which deliver around 96 mAh/g normalized capacity at 50 mA/g. This performance demonstrates that MoS2 has significant role in future commercial devices.

Keywords

• MoS2 electrode
• MoS2-CNT interactions
• Customized synthesis
• Electrochemical sodiation/desodiation