  Because inorganic solid electrolytes are one of the key components for
application to all-solid-state batteries, high-ionic-conductivity materials
must be developed. Therefore, we propose a method of efficiently evaluating the
activation energy of ionic diffusion by calculating a potential-energy surface
(PES), searching for the optimal diffusion path by an algorithm developed using
dynamic programming (DP), and calculating the corresponding activation energy
by the nudged elastic band (NEB) method. Taking beta-Li3PS4 as an example, the
activation energy of Li-ion diffusion was calculated as 0.43, 0.25, and 0.40 eV
in the a-, b-, and c-axis directions, respectively, which is in good agreement
with previously reported values. By comprehensively searching for the lowest
energy path by PES-DP, the arbitrariness of the path selection can be
eliminated, and the activation energy must only be calculated using the NEB
method a few times, which greatly reduces the computational cost required for
evaluating activation energy and enables the high-throughput screening of solid
state electrolytes.
