Fan Rujing, Yang Biao, Li Zhiwei, Ma Dandan, Yuan Wendong, Ma Jianyi, Ren Haisheng
Institute of Atomic and Molecular Physics, Sichuan University Chengdu Sichuan 610065 China
Engineering Research Center of Combustion and Cooling for Aerospace Power, Ministry of Education, Sichuan University Chengdu Sichuan 610065 China.
RSC Adv. 2020 Aug 28;10(53):31881-31888. doi: 10.1039/d0ra03635h. eCollection 2020 Aug 26.
Based on first principles calculation, the adsorption properties of Li atoms and LiF molecules on the fluorographene (CF ) surface with different F/C ratios ( = 1.0, 0.9, 0.8, 0.5 and ∼0.0) have been studied in the present work. The calculated binding energy of Li and CF is greater than 2.29 eV under different F/C ratios, indicating that the battery has the potential to maintain a high discharge platform during the whole discharge process. But the adsorption energies of LiF on a CF layer for different F/C ratios are 0.12-1.04 eV, which means LiF is not easy to desorb from a CF surface even at room temperature. It will stay on the surface for a long time and affect the subsequent discharge. Current calculations also show the structure of the CF -skeleton will change greatly during the reaction, when there are many unsaturated carbon atoms on the CF surface, such as at = 0.8 and 0.5. Moreover, the discharge voltage is strongly dependent on the discharge site. After discharge, the CF -skeleton may continue to relax and release a lot of heat energy.
基于第一性原理计算，本工作研究了不同F/C比（= 1.0、0.9、0.8、0.5和~0.0）下锂原子和LiF分子在氟化石墨烯（CF ）表面的吸附特性。在不同F/C比下，计算得到的Li与CF 的结合能大于2.29 eV，这表明该电池在整个放电过程中有可能保持较高的放电平台。但不同F/C比下LiF在CF 层上的吸附能为0.12 - 1.04 eV，这意味着即使在室温下LiF也不易从CF 表面解吸。它会在表面停留很长时间并影响后续放电。当前计算还表明，在反应过程中CF 的骨架结构会发生很大变化，例如在 = 0.8和0.5时，CF 表面存在许多不饱和碳原子。此外，放电电压强烈依赖于放电位点。放电后，CF 的骨架可能会继续弛豫并释放大量热能。
