Transition Metal Carbo-Chalcogenide "TMCC:" A New Family of 2D Materials

Here, a new family of 2D transition metal carbo-chalcogenides (TMCCs) is reported, which can be considered a combination of two well-known families, TM carbides (MXenes) and TM dichalcogenides (TMDCs), at the atomic level. Single sheets are successfully obtained from multilayered Nb₂ S₂ C and Ta₂ S₂ C using electrochemical lithiation followed by sonication in water. The parent multilayered TMCCs are synthesized using a simple, scalable solid-state synthesis followed by a topochemical reaction. Superconductivity transition is observed at 7.55 K for Nb₂ S₂ C. The delaminated Nb₂ S₂ C outperforms both multilayered Nb₂ S₂ C and delaminated NbS₂ as an electrode material for Li-ion batteries. Ab initio calculations predict the elastic constant of TMCC to be over 50% higher than that of TMDC.