Advances in Defect Engineering Enhances Lithium-Ion Battery Anodes

Recently, niobium-based oxides represent promising anodes due to various advantages, including enhanced safety, nontoxicity, and excellent structure stability. Unfortunately, the unsatisfactory ionic/electronic conductivity hampers the widespread application of such anodes in lithium-ion batteries (LIBs). As a solution to address the above issues, numerous efforts have been dedicated to electrochemical performance enhancements of the anodes, such as cyclic life and rate capacity, via defect engineering. First, the crystal structure, working mechanism, and underlying challenges of niobium-based oxides are briefly introduced. Alternatively, the review summarizes research progress on strategies to introduce various types of defects. Centered around aforementioned positive effects of defects on electrochemical performances of niobium-based oxides, we present an analysis of how defects improve ionic/electronic conductivity, followed by providing a detailed classification of intrinsic mechanisms behind electrochemical performance enhancement. Finally, this review provides an outlook on challenges and future research directions, offering perspectives to stimulate new ideas in developing defect-rich niobium-based oxide anodes.