Unravelling the Fast Alkali‐Ion Dynamics in Paramagnetic Battery Materials Combined with NMR and Deep‐Potential Molecular Dynamics Simulation
Min Lin, Xiangsi Liu, Yuxuan Xiang, Feng Wang, Yun‐Pei Liu, Riqiang Fu, Jun Cheng, Yong Yang
Abstract
Abstract Solid‐state nuclear magnetic resonance (ssNMR) has received extensive attention in characterizing alkali‐ion battery materials because it is highly sensitive for probing the local environment and dynamic information of atoms/ions. However, precise spectral assignment cannot be carried out by conventional DFT for high‐rate battery materials at room temperature. Herein, combining DFT calculation of paramagnetic shift and deep potential molecular dynamics (DPMD) simulation to achieve the converged Na + distribution at hundreds of nanoseconds, we obtain the statistically averaged paramagnetic shift, which is in excellent agreement with ssNMR measurements. Two 23 Na shifts induced by different stacking sequences of transition metal layers are revealed in the fast chemically exchanged NMR spectra of P2‐type Na 2/3 (Mg 1/3 Mn 2/3 )O 2 for the first time. This DPMD simulation auxiliary protocol can be beneficial to a wide range of ssNMR analysis in fast chemically exchanged material systems.