Abstract
VO2(B) is considered as a promising anode material for the
next-generation sodium-ion batteries (SIBs) due to its accessible raw
materials and considerable theoretical capacity. However, the VO2(B)
electrode has inherent defects such as low conductivity and serious
volume expansion, which hinder their practical application. Herein, a
flower-like VO2(B)/V2CTx (VO@VC) heterojunction was prepared by a simple
hydrothermal synthesis method with in situ growth. The flower-like
structure composed of thin nanosheets alleviates the volume expansion,
as well as the rapid Na+ transport pathways are built by the
heterojunction structure, resulting in long-term cycling stability and
superior rate performance. At a current density of 100 mA g-1, VO@VC
anode can maintain a specific capacity of 276 mAh g-1 with an average
coulombic efficiency of 98.7% after 100 cycles. Additionally, even at a
current density of 2 A g-1, the VO@VC anode still exhibited a capacity
of 132.9 mAh g-1 for 1000 cycles. The enhanced reaction kinetics can be
attribute to the fast Na+ adsorption and storage at interfaces, which
has been confirmed by the experimental and theoretical methods. These
results demonstrate that the tailored nanoarchitecture design and
additional surface engineering are effective strategies for optimizing
vanadium-based anode.