Mechanism of Na-Ion Conduction in the Highly Efficient Layered Battery Material Na₂Mn₃O₇

The ionic conduction properties of the technologically important two-dimensional (2D) layered battery material Na2Mn3O7, with exceptional small-voltage hysteresis between charge and discharge curves, have been investigated as a function temperature frequency by an impedance spectroscopy. detailed analyses data in form dc-conductivity, ac-conductivity, electrical modulus, dielectric constant complex polarizability reveal long-range Na-ionic conductivity negligible contribution from local dipole relaxation. A significant enhancement (~10^4 times) Na-ion has found increasing 353 K to 713 K. dependent reveals thermally activated process activation energies 0.161 0.377 eV over two regions 383-518 518-713 K, respectively. AC study hopping for carriers sharp increase range at 518 scaling ac-conductivity that frequency-activated (above 10^4 Hz K) is mainly controlled critical increases temperature. Na2Mn3O7 occurs predominantly correlated barrier process. Besides, correlation crystal structure established x-ray neutron diffraction study. We further shown can be enhanced reduction stacking faults structure. Our facilitates understanding microscopic mechanism highly efficient 2D having high energy storage capacity structural stability, paving way discovery materials applications.