MXene-derived three-dimensional carbon nanotube network encapsulate CoS2 nanoparticles as an anode material for solid-state sodium-ion batteries.

Solid state sodium-ion batteries (SSIBs) are promising energy storage devices due to the advanced safety and abundant natural sodium sources. However, the developments of SSIBs are seriously limited by the shortage of choice for both solid state electrolytes and anode materials. To cater to this problem, we provide a composite of cobalt disulfide and carbon nanotubes grown in situ on MXene and a derivative grown out of MXene during the prepared process (named as CoS₂/CNTs/TiO_xN_y) as an anode material, and PFSA-Na membranes as the solid-state electrolyte for SSIBs. The as-suggested SSIBs based on CoS₂/CNTs/TiO_xN_y and PFSA-Na membranes demonstrate promising electrochemical properties under room temperature, which is a significant improvement compared with the high-temperature running SSIBs. Furthermore, the electrochemical mechanism of CoS₂/CNTs/TiO_xN_y in the SSIBs was investigated by in situ Raman and ex situ XPS analyses to understand the reaction mechanism. [ABSTRACT FROM AUTHOR]