层状Ti_(2)C对Na储能性能的第一性原理研究

First-principles Study on the Na Energy Storage Properties of Layered Ti_(2)C

MXenes材料由于其独特的物理和化学性质,在低维功能材料研究领域引起了广泛的关注.采用密度泛函理论研究了Ti_(2)C作为层状材料,其层间相互作用对储Na电化学性能的影响,并探讨层状Ti_(2)C作为Na^(+)电池电极的可行性.计算结果表明,Ti_(2)C吸附单层Na^(+)时,吸附能为负值,证明吸附单层Na^(+)是可行的.单层Na^(+)嵌入层状Ti_(2)C结构,可以明显提高层状Ti_(2)C的片层间距,有助于后续Na^(+)的吸附.Ti_(2)C吸附双层Na^(+)时,吸附能仍为负值,且单、双层Na^(+)吸附后结构仍保持类金属特性,从理论上证明了层间Ti_(2)C作为Na^(+)电池电极材料的可行性,为层状Ti_(2)C作为Na^(+)电池电极提供了理论参照.

MXenes have attracted extensive attention in the field of low-dimensional functional materials research due to their unique physical and chemical properties.In this paper,the density functional theory is used to study the effect of Ti_(2)C as a layered material,its interlayer interaction on the electrochemical performance of storing Na^(-ion),and to explore the feasibility of the layered Ti_(2)C as the electrode of Na-ion batteries.The calculation results show that when Ti_(2)C adsorbs the single-layer Na^(-ion),the adsorption energy is negative,which prove that the adsorption of single-layer Na^(-ion)is feasible.The intercalation of single-layer Na^(-ion)into the layered Ti_(2)C configuration can significantly increase the interlamellar spacing of the layered Ti_(2)C configurations,which is beneficial to the subsequent adsorption of Na^(-ion).When Ti_(2)C adsorbs double-layer Na^(-ion),the adsorption energy is still negative,and the configurations of single-layer and double-layer Na^(-ion)adsorbed still maintains metal-like properties,which theoretically proves the feasibility of layered Ti_(2)C as an electrode material for Na-ion batteries.It provides a theoretical reference for the layered Ti_(2)C as an electrode of Na-ion batteries.