Simultaneously Enhanced Low Temperature Li+ Transport Kinetics and Crystal Stability of Nb1.94Mo0.06O5@C Anode Induced by Distorted NbO6 Octahedron

Abstract The electrochemical performances of lithium‐ion batteries (LIBs) will be significantly degraded under low‐temperature conditions, which restricts their wide application in cold environments. Herein, the low‐temperature transport kinetics of a novel Nb 1.94 Mo 0.06 O 5 @C nanocomposite anode is accelerated greatly via engineering the microstructure and NbO 6 octahedron. The detailed crystallographic features are characterized by using synchrotron radiation, spherical electron microscope, and density functional theory simulation methods. Both experimental and simulation analysis suggest that Mo 6+ preferentially replaces Nb 5+ in the regular octahedral location and distorts the NbO 6 octahedron, resulting in a widened c ‐axis spacing and a lowered ion diffusion barrier. Coupled with the enhanced electronic conductivity derived from surface carbon layer, Nb 1.94 Mo 0.06 O 5 @C anode exhibits an enhanced charge transfer process, improved Li + diffusion kinetics, pronounced pseudo‐capacitance process, and excellent low temperature capacity. Furthermore, in situ X‐ray diffraction and ex situ electron microscope elucidate that the structural evolution of Nb 1.94 Mo 0.06 O 5 @C is highly reversible, unveiling its excellent cycling stability. The full cell assembled with LiNi 0.6 Co 0.2 Mn 0.2 O 2 cathode demonstrates excellent practicality. This study reveals the critical role of distorting NbO 6 octahedron and expanding crystal spacing in facilitating rapid Li + diffusion and enhancing charge storage performance of Nb 2 O 5 at low temperatures.