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 Li2‐xZnTi3‐xNbxO8 (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.

Preparation and Electrochemical Performance of the Ni-Rich Co-Free Cathode Material LiNi0.94Mn0.04Al0.02O2

“…15,16 Lithium ratios are critical in the synthesis of high-nickel cathode materials; the amount of lithium not only affects the specific capacity and cycle performance of the material but also directly affects the free lithium content of the material surface and the pH value of the material. 17,18 Therefore, the amount of lithium in the material must be strictly controlled. 19−21 If the amount of lithium is too high, it increases the production cost.…”

“…Mn and Al elements are introduced into the layered high-nickel cobalt-free cathode material to solve the structural defects caused by the absence of Co elements. , However, there are still many shortcomings, such as Li + /Ni 2+ mixing intensification, poor rate performance, and so on. , Therefore, it is necessary to systematically study these structural defects of high-nickel cobalt-free cathode materials during the synthesis process. , Lithium ratios are critical in the synthesis of high-nickel cathode materials; the amount of lithium not only affects the specific capacity and cycle performance of the material but also directly affects the free lithium content of the material surface and the pH value of the material. , Therefore, the amount of lithium in the material must be strictly controlled. − If the amount of lithium is too high, it increases the production cost. It will also lead to high residual alkali content on the surface of the material, affecting the stability of the material cycle.…”

Li-storage of Li2ZnTi3O8@C-N anodes with high-performance in a wide temperature range

“…as the intercalation reaction anodes have relatively large speci c capacities and stable structures. Among the Li 2 MTi 3 O 8 family, Li 2 ZnTi 3 O 8 (LZTO) with the spinel structure is promising [9,10].…”