  Although two-dimensional transition metal carbides and nitrides (MXenes) have
fantastic physical and chemical properties as well as wide applications, it
remains challenging to produce stable MXenes due to their rapid structural
degradation. Here, unique metal-bonded atomic layers of transition metal
carbides with high stabilities are produced via a simple topological reaction
between chlorine-terminated MXenes and selected metals, where the metals enable
to not only remove Cl terminations, but also efficiently bond with adjacent
atomic MXene slabs, driven by the symmetry of MAX phases. The films constructed
from Al-bonded Ti$_3$C$_2$Cl$_x$ atomic layers show high oxidation resistance
up to 400 degrees centigrade and low sheet resistance of 9.3 ohm per square.
Coupled to the multi-layer structure, the Al-bonded Ti$_3$C$_2$Cl$_x$ film
displays a significantly improved EMI shielding capability with a total
shielding effectiveness value of 39 dB at a low thickness of 3.1 micron,
outperforming pure Ti$_3$C$_2$Cl$_x$ film.
