Perfect Planar Tetra-Coordinated MC6 Monolayer: Superior Anode Material for Li-ion Battery

For the past decades, the world has observed great achievement on theoretical prediction and experimental fabrication of two-dimensional transition metal carbides. In this work, we report a hitherto unknown atomic-thin planar-structured transition metal carbide sheet named MC6 (M=Cu, Ag, Au) via structure-swarm intelligence algorithm. The proposed 2D crystals are both statically and dynamically stable, and could maintain their structure integrity at temperatures up to 1500 K. The calculated specific capacities of lithium-ion batteries reach 1188 mAh g−1, which is 26.38 % higher than previously reported highest MXene material with Mn+1Xn atomic configuration. Our results present the potential application of MC6 on Li-ion batteries.