Enhanced lithium-ion transport in Nb5+ Doping Li2ZrCl6 solid electrolytes

Li 2 ZrCl 6 has emerged as a promising candidate material due to its notable cost-effectiveness compared to other complex halide superionic conductors. However, its relatively low ionic conductivity at room temperature remains a significant obstacle in practical applications. Doping serves as a prevalent strategy to enhance ion transport capabilities by modulating the lattice structure. In this work, Li 2-x Zr 1-x Nb x Cl 6 electrolyte is synthesized by doping Nb 5+ into Li 2 ZrCl 6 . Nb 5+ doping enhances Li + transport dynamics through a dual mechanism involving vacancies and structural modifications. The ionic conductivity of the modified Li 1.85 Zr 0.85 Nb 0.15 Cl 6 reaches 0.70 mS·cm −1 at room temperature, more than doubling that of Li 2 ZrCl 6 . Furthermore, the electrochemical performance of an all-solid-state battery utilizing Li 1.85 Zr 0.85 Nb 0.15 Cl 6 electrolyte paired with NCM811 cathode is evaluated. The results demonstrate that Nb 5+ doping significantly enhances the specific discharge capacity and cycle stability of Li 2 ZrCl 6 . These findings provide valuable insights into enhancing the ionic conductivity of zirconium-based solid electrolyte systems through the doping of high-valence ions.