Conductive LaCeNb6O18 with a Very Open A‐Site‐Cation‐Deficient Perovskite Structure: A Fast‐ and Stable‐Charging Li+‐Storage Anode Compound in a Wide Temperature Range

Abstract Li 4 Ti 5 O 12 (LTO) is the most famous Li + ‐storage anode material with fast‐ and stable‐charging capability, but suffers from several disadvantages, such as poor electron conduction, low energy density, and disappointing high‐temperature performance. Here, LaCeNb 6 O 18 (LCNO) micrometer‐sized particles are explored as a fast‐ and stable‐charging anode material superior to LTO sub‐micrometer‐sized particles in terms of the working potential, rate capability, and high‐temperature performance. The conductive Ce 3+ and Nb 5+ ↔ Nb 3+ reactions in LCNO, respectively, enable its significantly larger electronic conductivity and lower working potential than those of LTO. LCNO owns a very open A‐site‐cation‐deficient perovskite structure, in which (vacancy/La/Ce)O 12 layers with electrochemical inactivity and superior volume‐buffering capability locate between active NbO 6 layers, leading to not only fast Li + diffusivity but also low‐ and negative‐strain behavior at different temperatures. At 25 ° C, LCNO exhibits higher rate capability (50 vs 0.1 C capacity ratio of 67.9%) than that of LTO, and excellent cyclability. At 60 ° C, LCNO maintains excellent cyclability, and achieves larger reversible capacity and even higher rate capability, whereas the high temperature lowers all the electrochemical properties of LTO. Therefore, LCNO holds great promise for fast‐ and stable‐charging applications in a wide temperature range, even when its particle sizes are on the order of micrometers.