Synthesis and Lithium Storage Properties of Co₃O₄ Nanosheet‐Assembled Multishelled Hollow Spheres

Abstract

Single‐, double‐, and triple‐shelled hollow spheres assembled by Co3O4 nanosheets are successfully synthesized through a novel method. The possible formation mechanism of these novel structures was investigated using powder X‐ray diffraction, scanning and transmission electron microscopies, Fourier transform IR, X‐ray photoelectron spectroscopy, and thermogravimetric analysis. Both poly(vinylpyrrolidone) (PVP) soft templates and the formation of cobalt glycolate play key roles in the formation of these novel multishelled hollow structures. When tested as the anode material in lithium‐ion batteries (LIBs), these multishelled microspheres exhibit excellent cycling performance, good rate capacity, and enhanced lithium storage capacity. This superior cyclic stability and capacity result from the synergetic effect of small diffusion lengths in the nanosheet building blocks and sufficient void space to buffer the volume expansion. This facile strategy may be extended to synthesize other transition metal oxide materials with hollow multishelled micro‐/nanostrucutures, which may find application in sensors and catalysts due to their unique structural features.

Evaluating the performance of nanostructured materials as lithium-ion battery electrodes

“…Although the unique structuring enabled high capacity at relatively low rates, the nanobelts ultimately suffered from poor rate performance, with stable capacities only obtained at C-rate [195]. Other recent examples of Co3O4 nanostructures demonstrated include nanosheets [196], multi-shelled hollow spheres [197] and octahedral nanocages [198]. Of these examples, the 2D nanosheet structures prepared by Zhan et al [196], offered considerable capacity, to as much as 1450 mA h g -1 at the 27 th cycle (end of test).…”

A facile method to improve the high rate capability of Co3O4 nanowire array electrodes

“…Co 3 O 4 has been demonstrated to be a promising electrode material for LIBs and pseudo-type SCs due to its low environmental footprint, low cost and extremely high theoretical specific capacitance (3560 F/g) for SCs and capacity (890 mA·h/g) for LIBs [5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21][22]. Furthermore, cobalt oxide directly grown on current collectors in the form of highly oriented nanowires (NWs) has several additional advantages for applications in electrodes [2].…”

High-rate lithiation-induced reactivation of mesoporous hollow spheres for long-lived lithium-ion batteries

“…Hierarchically meso-and nanoporous hollow spheres are recognized as promising electrode materials for electrochemical energy storages [19][20][21][22][23][24] , and the unique structure provides an enhanced surface-to-volume ratio and reduced lengths for both mass and charge transports. The hollow sphere also provides extra space to mitigate volume expansion/extraction, thus displaying enhanced cycling stabilities, particularly at low current densities.…”