Ab initio prediction of borophene as an extraordinary anode material exhibiting ultrafast directional sodium diffusion for sodium-based batteries

作     者：Le Shi Tianshou Zhao Ao Xu Jianbo Xu 

作者机构：Department of Mechanical and Aerospace Engineering The Hong Kong University of Science and Technology 

出 版 物：《Science Bulletin》 (科学通报（英文版）)

年 卷 期：2016年第61卷第14期

页      面：1138-1144页

核心收录：

学科分类：081704[工学-应用化学] 08[工学] 0817[工学-化学工程与技术] 

基　　金：supported by a Grant from the Research Grants Council of the Hong Kong Special Administrative Region China(16213414) 

主　　题：Borophene - Sodium anode Directionaldiffusion Ultrafast diffusivity 

摘      要：Density functional theory calculations and ab initio molecular dynamics simulations are performed to study the feasibility of using borophene, a newly synthesized two-dimensional sheet of boron, as an anode material for sodium-ion and sodium-oxygen batteries. The theo- retical capacity of borophene is found to be as high as 1,218 mAh g-1 （***）. More importantly, it is demonstrated that the sodium diffusion energy barrier along the valley direction is as low as 0.0019 eV, which corresponds to a diffusivity of more than a thousand times higher than that of conventional anode materials such as Na2Ti307 and Na3Sb. Hence, the use of borophene will revolutionize the rate capability of sodium-based batteries. Moreover, it is predicted that, during the sodiation process, the average open-circuit voltage is 0.53 V, which can effectively sup- press the formation of dendrites while maximizing the energy density. The metallic feature and structural integrity of borophene can be well preserved at different sodium concentrations, demonstrating good electronic conductivity and stable cyclability.