Conductive Copper Niobate: Superior Li+‐Storage Capability and Novel Li+‐Transport Mechanism

Abstract Niobates with shear ReO 3 crystal structures are remarkably promising anode materials for Li + batteries due to their large capacities, inherent safety, and high cycling stability. However, they generally suffer from limited rate capabilities rooted in their insufficient electronic and Li + conductivities. Here, micrometer‐sized copper niobate (Cu 2 Nb 34 O 87 ) bulk as a new anode material having a high electronic conductivity of 2.1 × 10 −5 S cm −1 and an impressive average Li + diffusion coefficient of ≈3.5 × 10 −13 cm 2 s −1 is exploited, which synergistically leads to an excellent rate capability (184 mAh g −1 at 10 C) while remaining a large reversible capacity and superior cycling stability. Moreover, the fast Li + transport pathways of grain boundary (micrometer scale) → lattice deformation area (nanometer scale) → (010) crystallographic plane (angstrom scale) are demonstrated in Cu 2 Nb 34 O 87 . Therefore, these results could pave the way for practical application of Cu 2 Nb 34 O 87 in high‐performance Li + batteries.