Modulating the Stoichiometry and Lithium Content to Boost the Electrochemical Performance of Li₂ZnTi₃O₈ via High Valence Nb⁵⁺ Dopants

Abstract A series of anode materials with the general formula of Li₂ZnTi₃O₈ (LZTO) and Li_2‐xZnTi_3‐xNb_xO₈ (x = 0.2, 0.4, and 0.5) (LZTNO) are designed. Different amount of high valence Nb⁵⁺ dopants not only reduces the content of lithium in LZTO but also alters the intrinsic characteristics of the composites, leading to optimized electrochemical performances. XRD, SEM, TEM, and XPS results suggest that Nb dopants are introduced successfully, but large amount of Nb⁵⁺ dopants (x > 0.2) result in the formation of ZnNb₂O₆ and TiO₂. Owing to the small particle size and the improved structural stability, LZTNO‐2 sample exhibits the best electrochemical performance, and it can deliver a charge/discharge capacity of 182.7/181.2 mAh g⁻¹ at 1 A g⁻¹ after 500 cycles, which is much higher than the value of LZTO (100.41/100.41 mAh g⁻¹). The experiments suggest that the introduction of high valence dopants can effectively modulate the stoichiometry and lithium content of the anode materials, making the available vacant sites for subsequent intercalation of lithium obviously extended. Such a strategy is expected to be feasibly applied to other anode materials to enhance their specific capacity and electrochemical performances.