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This study demonstrates that the ionic conductivity of crystalline NaTaCl₆ (NTC) solid electrolytes can be significantly enhanced through the introduction of Na and Cl Schottky defects without inducing amorphization, achieving a conductivity of 4.77 × 10-4 S/cm. While previous improvements have largely focused on amorphization via high-energy ball milling, our combined experimental and computational analysis reveals that defect engineering plays a pivotal and complementary role. The vacancies diversify local Na environments and flatten the energy landscape for ion migration. These findings highlight the potential of controlled defect formation as a robust strategy for designing high-performance solid electrolytes for ASSSBs.

(ACS Energy Letters, Online Published (2025) [Journal Website])

This work presents a significant advancement in the understanding of the intricate chemo-mechanical degradation mechanisms in all-solid-state batteries (ASSBs) through a quantitative multi-length scale analysis, highlighting the novel functionality of the coating layer. We found that uncontrolled interfacial reactions and point-contact interfaces in uncoated cathode lead to heterogeneous particle reactions and uneven mechanical degradation. In contrast, the LiDFP coating not only mitigates the chemical decomposition of the solid electrolyte but also maintains enhances the reaction uniformity among particles and homogenizes mechanical degradation.

(Nature Communications, Accepted)

In our study, we present a strategy to design structurally reversible conversion-type positive electrode materials by guiding favorable phase transitions. We demonstrate that forming a LiF-FeF2 nanocomposite enables the electrochemical synthesis of metastable tetragonal FeF3 (T-FeF3), which exhibits superior reversibility compared to conventional rhombohedral FeF3 (R-FeF3). Unlike R-FeF3, which undergoes irreversible structural rearrangements and induces compositional inhomogeneity during lithiation, T-FeF3 maintains structural similarity to FeF2, enabling smooth and reversible insertion–conversion reactions. This guided transition pathway suppresses long-range atomic diffusion and minimizes voltage hysteresis. Our findings highlight that phase transitions between structurally analogous intermediates can be intentionally induced to mitigate structural degradation.

(Nature Communications, Accepted)