  Designing anode materials with high lithium specific capacity is crucial to
the development of high energy-density lithium ion batteries. Herein, a
distinctive lithium growth mechanism, namely, the restricted multilayered
growth for lithium, and a strategy for lithium storage are proposed to achieve
the balance between the ultra-high specific capacity and the need to avert
uncontrolled dendritic growth of lithium. In particular, based on
first-principles computation, we show that the Al2C monolayer with planar
tetracoordinate carbon structure can be an ideal platform for realizing the
restricted multilayered growth mechanism as a 2D anode material. Furthermore,
the Al2C monolayer exhibits ultra-high specific capacity of lithium of 4059
mAh/g, yet with a low dif-fusion barrier of 0.039-0.17 eV as well as low open
circuit voltage in the range of 0.002-0.34 V. These novel properties endow the
Al2C monolayer a promising anode material for future lithium ion batteries. Our
study offers a new way to design promising 2D anode materials with high
specific capacity, fast lithium-ion diffusion, and safe lithium storage
mechanism.
