Breaking structural symmetry to facilitate fast reaction kinetics

Abstract

Breaking the intrinsic symmetry in crystal structures has emerged as a powerful strategy to enhance electrochemical reaction kinetics in advanced battery materials. In this study, we systematically investigate how introducing larger heteroatoms (e.g., Se, Te) into a cubic host lattice disrupts its symmetry, thereby creating new pathways for ionic transport. By expanding and splitting bond lengths, doping weakens the local bonding environment and reduces chemical hardness, which in turn lowers the energy barriers for (de)lithiation and accelerates phase-transition kinetics. Furthermore, Li kinetic calculations reveal that the resultant lattice distortions give rise to multiple diffusion routes, including newly formed channels with notably lower migration barriers. These findings underscore the critical role of structural asymmetry in improving charging rates and mitigating voltage hysteresis. Overall, this work highlights symmetry breaking as a promising design concept for developing high-performance battery materials, offering a pathway to faster Li-ion transport.