From high-yield Ti3AlCN ceramics to high-quality Ti3CNTx MXenes through eliminating Al segregation

Ti3CNTx MXenes with unique electrical conductivity can be widely applied for supercapacitors and electromagnetic shielding.However,its relatively low-yield quaternary nitrogen-containing Ti3AlCN ce ramics precursor(less than 50%),due to the inevitable Al segregation during the synthesizing process,significantly hindered its widely commercial applications.Herein,we employed the controllable AlNoversaturation precursor strategy to precisely tune the phase transition point of quaternary Ti3AlCN ceramics to obtain high-yield Ti3 AlCN precursor for the purpose of high conductivity Ti3 CNTx MXenes.Combined energy dispersive X-ray spectrometer(XRD)with X-ray photoelectron spectroscopy(XPS)characterizations,the yield of the quaternary nitrogen-containing Ti3 AlCN ceramics was evidently proved to be up to 70%,which is 1.4 times than that of previously reported works.Such relatively highyield quaternary Ti3AlCN is mainly ascribed to the elimination of Al segregation.Based on it,we further developed accordion-like two-dimensional(2D)MXene via hydrofluoric acid etch and vacuum freezedry.This novel accordion-like 2D Ti3CNTx MXene possesses high electrochemical capacitive properties(209 F/g).Therefore,this controllable AlN-oversaturation precursor strategy will pave a way to exploit costly high-yield MAX ceramics precursor for high conductivity MXenes and also play a powerful role in promoting their practical applications including electrical and magnetic engineering fields.