Electrochimica Acta, Vol.298, 449-458, 2019
Inducing -orientation in Nb2O5 capsule-nanostructure for promoted Li+ diffusion process
Controlling the growth of (001) lattice plane for orthorhombic niobium pentoxide is an effective method to enhance its electrochemical performance. Herein, the oriented Nb2O5@C nanorods with capsule structure which grows along the perpendicular direction to the (001) lattice plane are successfully fabricated by a hydrothermal method with a later heat treatment process. As an anode for Li-ion batteries, the oriented Nb2O5@C composite delivers an ultralong cycling stability of 200mAh g(-1) after 1000 cycles at 5 A g(-1) and enhanced rate capability of 413 and 143 mAh g(-1) at 0.1 and 5 A g(-1) respectively, which are much better than those of Nb2O5 electrode. Further investigations reveal that the oriented Nb2O5@C composite shows lower charge-transfer resistance, higher Li+ diffusion coefficient and maintains a surface-controlled pseudocapacitive mechanism. The superior performances are ascribed to the synergetic effect of -orientation, small Li+ diffusion lengths in the nanorods building flowers and capsule-nanostructure with uniform carbon coating. (C) 2018 Elsevier Ltd. All rights reserved.