Facile Fabrication of Porous Ni_xCo_3–xO₄ Nanosheets with Enhanced Electrochemical Performance As Anode Materials for Li-Ion Batteries

Abstract

Herein, we report a novel and facile route for the large-scale fabrication of 2D porous NixCo3-xO4 nanosheets, which involves the thermal decomposition of NixCo1-x hydroxide precursor at 450 °C in air for 2 h. The as-prepared 2D porous NixCo3-xO4 nanosheets exhibit an enhanced lithium storage capacity and excellent cycling stability (1330 mA h g(-1) at a current density of 100 mA g(-1) after 50 cycles). More importantly, it can render reversible capacity of 844 mA h g(-1), even at a high current density of 500 mA g(-1) after 200 cycles, indicating its potential applications for high power LIBs. Compared to pure Co3O4, the reduction of Co in NixCo3-xO4 is of more significance because of the high cost and toxicity of Co. The improved electrochemical performance is attributed to the 2D structure and large amounts of mesopores within the nanosheets, which can effectively improve structural stability, reduce the diffusion length for lithium ions and electrons, and buffer volume expansion during the Li(+) insertion/extraction processes.

A Simple Synthesis of Two-Dimensional Ultrathin Nickel Cobaltite Nanosheets for Electrochemical Lithium Storage

“…Deduced from the desorption branch based on the BJH method, the dominant pore sizes distribution are calculated to be about 2.07 nm with a total pore volume of 0.5922 cm 3 g À1 . Moreover, the ultrathin NiCo 2 O 4 nanosheets exhibit a high BrunauerÀEmmettÀTeller (BET) specific surface area of 126.46 m 2 g À1 , which is much higher than the reported values of the relevant NiCo 2 O 4 nanostructures, such as nanoflakes and nanobelts (54 and 66 m 2 g À1 ) [17], mesoporous microspheres (40.58 m 2 g À1 ) [18], hollow nanospheres (59.88 m 2 g À1 ) [19], hollow nanocubes (82.25 m 2 g À1 ) [45], Ni x Co 3Àx O 4 nanosheets (21.3 m 2 g À1 ) [46], and flower (80.1 m 2 g À1 ) [47]. Such competitive BET value could be attributable to the unique architecture of the 2D ultrathin nanosheets with the extended and rough surfaces.…”

Facile preparation and performance of hierarchical self-assembly MnCo2O4 nanoflakes as anode active material for lithium ion batteries

“…The isotherm of hierarchical self-assembly MnCo 2 O 4 nanoflakes can be classified as type IV with a type H1 hysteresis loop, implying the existence of a large number of mesopores in the MnCo 2 O 4 sample [27]. As a result, the BET specific surface area is about 49.44 m 2 g À1 , which is slightly higher than that of the binary metal oxides reported, such as the 2D Ni x Co 3x O 4 nanosheets (21.3 m 2 g À1 ) [24]. As shown in the inset of Fig.…”

Fabrication of NiFe2O4/C hollow spheres constructed by mesoporous nanospheres for high-performance lithium-ion batteries

“…6d). The peak at 530.4 eV is ascribed to the metal-oxygen bonds [37,38], while the peak at 531.8 eV is usually associated with defects, adsorbed contaminants and other surface species including hydroxyls, chemisorbed oxygen, under-coordinated lattice oxygen [35,39].…”