Doping engineering of scandium‐based solid‐state electrolytes toward superior ionic conductivity
Hongtu Zhang,
Zhichao Zeng,
Xiaomeng Shi,
Chun‐Hai Wang,
Yaping Du
Affiliations
Hongtu Zhang
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensing Interdisciplinary Science Center, School of Materials Science and Engineering, National Institute for Advanced Materials Nankai University Tianjin China
Zhichao Zeng
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensing Interdisciplinary Science Center, School of Materials Science and Engineering, National Institute for Advanced Materials Nankai University Tianjin China
Xiaomeng Shi
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensing Interdisciplinary Science Center, School of Materials Science and Engineering, National Institute for Advanced Materials Nankai University Tianjin China
Chun‐Hai Wang
State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi'an China
Yaping Du
Tianjin Key Lab for Rare Earth Materials and Applications, Center for Rare Earth and Inorganic Functional Materials, Smart Sensing Interdisciplinary Science Center, School of Materials Science and Engineering, National Institute for Advanced Materials Nankai University Tianjin China
Abstract One key research point of solid‐state electrolytes (SSEs) is ionic conductivity. To date, their ionic conductivity is relatively low to meet the requirements of practical applications; thus, more investigations on the migration mechanisms are needed. Here, we constructed scandium‐based halide SSEs (Li3‐xSc1‐x(Zr/Hf)xCl6, x = 0 ~ 0.5). The highest ionic conductivities (1.61 and 1.33 mS/cm) and the lowest activation energies (0.326 and 0.323 eV) are shown in Li2.6Sc0.6Zr0.4Cl6 (LSZC~0.4) and Li2.6Sc0.6Hf0.4Cl6 (LSHC~0.4), respectively. Their electrochemical windows in the cells of Li/Li7P3S11/LSZC~0.4/LSZC~0.4‐C and Li/Li7P3S11/LSHC~0.4/LSHC~0.4‐C are 1.3 ~ 4.2 V and 1.6 ~ 4.1 V versus Li+/Li, respectively. The crystal structures and the Li+ chemical environments were investigated by X‐ray diffraction and 7Li solid‐state magic angle spinning nuclear magnetic resonance, indicating weaker bond strengths of LiCl to facilitate the transportation of Li+. The potential reason explaining the increased ionic conductivity was determined based on the bond valence site energy theory.
