VO₂ Nanosheets Assembled into Hierarchical Flower-Like Hollow Microspheres for Li-Ion Batteries

Abstract

Vanadium dioxide (VO2) is a prospering material for lithium-ion cathode storage attributed to its unique structure and high specific capacity. However, the cycling and rate performance of VO2 is unsatisfactory due to low electrical conductivity and tendency to volume expansion during charging and discharging, which restricts its application. To improve its cell performance, we report 3D hierarchical flower-like VO2 hollow microspheres assembled from nanosheets (HVO) synthesized by a facile template-free hydrothermal method. In addition, by controlling the content of nitric acid (HNO3) and citric acid (C6H8O7), VO2 flower-like solid microspheres (SVO) and random nanosheets (NVO) were synthesized as control experiments. Compared with them, 3D hierarchical flower-like VO2 hollow microspheres have higher reversible capacity (delivers a capacity of 259.90 mA h g–1 at 0.1 A g–1), extraordinary rate capacity (168.51 mA h g–1 at 2 A g–1), and good cycling life (81.21% capacity retention over 500 cycles at 2 A g–1). Moreover, the HVO//graphite full cell was successfully assembled, which exhibits an initial capacity of 147.17 mA h g–1 at 2 A g–1 and maintains a high capacity of 114.97 mA h g–1 after 1000 cycles, with capacity retention of 78.12% and an average capacity decline of 0.022% per cycle. The superior performance of 3D hierarchical flower-like VO2 hollow microspheres stems from their ability to provide a considerable surface area, efficient self-expansion, and self-shrinkage buffering. The abovementioned results sufficiently confirm that 3D hierarchical flower-like VO2 hollow microspheres constituted from nanosheets have great latent potential and application prospects as a next-generation cathode material for fast-charging lithium-ion batteries.

Solvothermal synthesis of VO2 nanoparticles with locally patched V2O5 surface layer and their morphology-dependent catalytic properties for the oxidation of alcohols

“…This allows the preparation of nanocrystals with different morphologies, e.g. , spheres, 43–45 rods, 46–49 sheets, 50–53 and urchins 54,55 only by varying the volume ratio of the solvents. 56…”

“…42 In binary solvent mixtures these factors can be tuned accurately and independently. This allows the preparation of nanocrystals with different morphologies, e.g., spheres, [43][44][45] rods, 46-49 sheets, [50][51][52][53] and urchins 54,55 only by varying the volume ratio of the solvents. 56 Sheet-and urchin-like morphologies are the most promising options for large surface areas, but the morphological effects can be offset by the particle size.…”

P-doping boosting electronic properties and ionic kinetics of MnV2O6 for high-performance lithium-ion batteries

“…1,[12][13][14] However, their viability in practi-cal batteries is hampered by their limitations of poor conductivity, inferior ion kinetics, and severe volume changes upon cycling. 2,[15][16][17] Although introducing a second metal cation into the structure can stabilize the framework of vanadium oxides, [18][19][20][21] unavoidable vanadium dissolution still occurs during cycling, which results in poor energy density, low rate performance, and bad structural stability. [22][23][24] Therefore, the preparation of stable vanadium oxide electrodes for LIBs is highly essential for applications.…”