1 research outputs found
Micro- and Nanocrystalline Inverse Spinel LiCoVO<sub>4</sub> for Intercalation Pseudocapacitive Li<sup>+</sup> Storage with Ultrahigh Energy Density and Long-Term Cycling
Intercalation pseudocapacitance
has been recognized as a new type of charge storage mechanism in crystalline
metal oxides, wherein Li<sup>+</sup> intercalation is not limited
to surface structures, instead extended to the bulk crystalline framework
of the material. This may possibly narrow the performance gap between
pseudocapacitors and batteries. Hitherto, very few crystalline materials
have been found to exhibit such an intrinsic capacitive property.
Here, we report for the first time that the inverse spinel LiCoVO<sub>4</sub> exhibits intercalation pseudocapacitive Li<sup>+</sup> storage
property in aqueous electrolyte. Micro- and nanocrystalline LiCoVO<sub>4</sub> were synthesized via conventional solid-state reaction and
hydrothermal reaction followed by calcination, respectively. In particular,
nanocrystalline LiCoVO<sub>4</sub> demonstrated better Li<sup>+</sup> intercalation benefited from its small crystallite size with highly
exposed Li<sup>+</sup> selective crystallographic pathways toward
electrolyte. The LiCoVO<sub>4</sub> nanocrystals demonstrated excellent
capacitive performance, including high specific capacitance (929.58
F g<sup>β1</sup> at 1 A g<sup>β1</sup>) and cycling
stability. Moreover, asymmetric hybrid cells were assembled using
nanocrystalline LiCoVO<sub>4</sub> and MWCNT as the positive and negative
electrode, respectively. The hybrid cells exhibited an unprecedented
energy density (148.75 Wh kg<sup>β1</sup> at a power density
of 264.6 W kg<sup>β1</sup>) and superior cycling stability
(94% capacitance retention after 5000 cycles)