Recent research progress on Li29Zr9Nb3O40-based solid electrolytes for lithium batteries
Abstract
All-solid-state batteries have become a research hotspot because of their high specific capacity and safety. Solid-state electrolytes are the key material of all-solid-state lithium-ion batteries, and their properties directly affect the overall performance of lithium-ion batteries. So far, many inorganic solid electrolytes have been reported, such as NASICON, LISICON, perovskite, and garnet-type solid electrolyte. However, some lithium-rich rock salt-structured electrolytes, such as Li2ZrO3, LiNbO4, and Li6Zr2O7, have been underappreciated in the field of solid-state electrolytes due to their lower ionic conductivity at room temperature. While investigating solid solution formation, Li6Zr2−xNbxO7+x/2, a new phase known as Li29Zr9Nb3O40 with a rock-salt structure was discovered. After decades, it was not until a team prepared Li29Zr9Nb3O40 ceramics by sol-gel method, which exhibited high ionic conductivity (10−5–10−3S cm−1) at room temperature, that the substance showed great potential as a solid electrolyte in all-solid-state lithium-ion batteries. In this paper, the crystal structure, lithium-ion transport mechanism, preparation method, and element doping of Li29Zr9Nb3O40 are described comprehensively based on research progress in recent years. Then, development prospects and challenges of the concrete application of Li29Zr9Nb3O40 in all-solid-state lithium-ion batteries are also discussed.
