Monolayer <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:msub><mml:mrow><mml:mrow><mml:mi mathvariant="normal">C</mml:mi></mml:mrow></mml:mrow><mml:mn>5</mml:mn></mml:msub><mml:mrow><mml:mrow><mml:mi mathvariant="normal">N</mml:mi></mml:mrow></mml:mrow></mml:math>: A Promising Building Block for the Anode of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><mml:mrow><mml:mrow><mml:mi mathvariant="normal">K</mml:mi></mml:mrow></mml:mrow></mml:math>-Ion Batteries
Junjie Jin, Geetanjali Deokar, Pedro M. F. J. Costa, Udo Schwingenschlögl
Abstract
Intercalation-type batteries based on the alkali metal $\mathrm{K}$, an earth-abundant element, are attracting increasing attention as alternatives to $\mathrm{Li}$-ion batteries. However, the lack of a high-performance anode limits the success of $\mathrm{K}$-ion batteries. Here, we study the performance of monolayer ${\mathrm{C}}_{5}\mathrm{N}$ as a potential building block for the anode. Our theoretical data show that the metallic monolayer can accommodate 2.25 K atoms per formula unit, which corresponds to a specific capacity of 814 mA h ${\mathrm{g}}^{\ensuremath{-}1}$, and provides a low diffusion barrier of only 0.11 eV. The volume change of bulk ${\mathrm{C}}_{5}\mathrm{N}$ (47%) is found to be smaller than that of graphite (61%; commercial anode material). These predictions will serve the design of future anode materials for $\mathrm{K}$-ion batteries.