Review on Characterization of Nano Sized MXenes for Energy Storage Devices

Complex layered structures occur in a wide range of ceramic materials. The so called �MAX phases� is an exciting playground for property tuning and understanding of process-structure-property relationships. They stand out because of the large variations in chemistry and hence design opportunities within the same materials family. Mn+1AXn (MAX) phases are nano-laminated compounds based on a transition metal (M), a group an element (A), and carbon or/and nitrogen (X), which exhibit a unique combination of ceramic and metallic properties. A new family of 2D materials has emerged, consisting of transition metal carbides, nitrides and carbonitrides, known as MXenes which are electrically conductive in nature. One of the many potential applications for 2D Ti3C2 is in electrical energy storage devices, such as batteries, Li-ion capacitors and super-capacitors. The vast majority of MXenes known till date have been produced by selectively etching Al from Al containing MAX phases. During the etching process, the MXene surface acquires terminating functional groups, which is why they are commonly designated as Mn+1XnTx, where Tx represents surface terminating groups such as -O, -OH, and/or �F.