Recent discoveries in the antiperovskite-class sodium superionic conductors call for a thorough mole cular dynamics(MD)study of sodium ion mobility,but the practical use of MD is often hindered by the accuracy-vs.-eff...Recent discoveries in the antiperovskite-class sodium superionic conductors call for a thorough mole cular dynamics(MD)study of sodium ion mobility,but the practical use of MD is often hindered by the accuracy-vs.-effciency dilemma.Here we applied the recently developed deep potential molecular dynamics(DeePMD)approach to investigate the ion mobility in Na_(3)OBr.With the deep potential model for Na_(3)OBr constructed based onfirst-principles density-functional theory(DFT)calculations,we directly calculate the Na+diffusion coeffcient at various temperatures,and obtain an activation energy of 0.42-0.43 eV.This in comparison with the 0 K migration barrier(0.41-0.43 eV)suggests that thefinite temperature effect is negligible for Na_(3)OBr.The model gives an extrapolated room temperature ionic conductivity of 1×10^(−4)-2×10^(−4)mS cm^(−1),roughly in the same order of magnitude as the experimental results.We also confirm the proportionality of the diffusion coeffcient with respect to the vacancy con centration,andfind that the migration barrier is relatively insensitive to the vacancy concentration.This work further demonstrates the promising role of the DeePMD method in the study of the transport pro perties of solid-state electrolytes.展开更多
基金supported by the National Key Research and Development Program of China(No.2016YFB0701100)the National Natural Science Foundation of China(Projects No.21673005 and 21621061)the High-performance Computing Platform of Peking University.
文摘Recent discoveries in the antiperovskite-class sodium superionic conductors call for a thorough mole cular dynamics(MD)study of sodium ion mobility,but the practical use of MD is often hindered by the accuracy-vs.-effciency dilemma.Here we applied the recently developed deep potential molecular dynamics(DeePMD)approach to investigate the ion mobility in Na_(3)OBr.With the deep potential model for Na_(3)OBr constructed based onfirst-principles density-functional theory(DFT)calculations,we directly calculate the Na+diffusion coeffcient at various temperatures,and obtain an activation energy of 0.42-0.43 eV.This in comparison with the 0 K migration barrier(0.41-0.43 eV)suggests that thefinite temperature effect is negligible for Na_(3)OBr.The model gives an extrapolated room temperature ionic conductivity of 1×10^(−4)-2×10^(−4)mS cm^(−1),roughly in the same order of magnitude as the experimental results.We also confirm the proportionality of the diffusion coeffcient with respect to the vacancy con centration,andfind that the migration barrier is relatively insensitive to the vacancy concentration.This work further demonstrates the promising role of the DeePMD method in the study of the transport pro perties of solid-state electrolytes.
基金supported by the National Natural Science Foundation of China (12032004, 11872114 and 11502150)the Natural Science Foundation of Hebei Province of China (A2016210060)+1 种基金the GHfund B (202202026154)Key Project of Natural Science Foundation of Hebei Province (Basic Discipline Research) (A2023210064)。
