Rational Design of Graphene-Reinforced MnO Nanowires with Enhanced Electrochemical Performance for Li-Ion Batteries

Abstract

Recently, transition metal oxides (TMOs) mixed with carbon materials have attracted attention as lithium-ion battery (LIB) anode materials. However, the aggregation issue in TMOs hinders the development of an ideal encapsulation structure with carbon materials. In this paper, we report graphene reinforced MnO nanowires with enhanced electrochemical performance as an anode in LIB. The graphene nanosheets (GNs)/MnO feature was confirmed by transmission electron microscopy, X-ray diffraction, Raman scattering, and X-ray photoelectron spectroscopy. The GNs/MnO nanowires delivered a highly stable discharge capacity of ∼815 mAh g(-1) at a current density of 100 mA g(-1) after 200 cycles, which is 1.5 times higher than that of pure MnO nanowires. This GNs/MnO structure with a specific capacity of ∼995 mAh g(-1) at a current density of 50 mA g(-1) also exhibited excellent Li storage properties. The superior cycling and high rate capability were attributed to the intimate incorporation between the MnO and GNs. The structure of the GNs/MnO nanowires effectively accommodated the volume change of the MnO nanowires and prevented structure collapse during cycling.

Molten‐Salt‐Assisted Synthesis of Hierarchical Porous MnO@Biocarbon Composites as Promising Electrode Materials for Supercapacitors and Lithium‐Ion Batteries

“…The Mn 2p core‐level spectrum (Figure d) exhibits two peaks at 641.7 (Mn 2p 3/2 ) and 653.7 eV (Mn 2p 1/2 ) with a separation of 12 eV, characteristic of MnO . The O 1s spectrum shows three peaks at 530.2, 531.4, 532.6 eV for Mn−O, C=O, and C−O bonds, respectively, indicative of residual oxygen‐containing functional groups due to insufficient carbonization of agaric. The oxygen‐containing residues may act as bridges joining the carbon matrix and MnO nanocrystals, which further facilitate the utilization of active MnO species for electrochemical energy storage.…”

“…The C1s core-level spectrum (Figure 3c)d isplays four peaks at 284.8, 285.9,2 87.2, and 289.4 eV,c orresponding to CÀC/C=C, CÀN/C=N, CÀO, and O=CÀOb onds, [19] respectively,w hich suggest oxygen-containing groups and an N-doped nature.T he Mn 2p core-level spectrum (Figure 3d)e xhibits two peaks at 641.7 (Mn 2p 3/2 )a nd 653.7 eV (Mn 2p 1/2 )w ith as eparation of 12 eV,c haracteristic of MnO. [20] The O1ss pectrum shows three peaks at 530.2, 531.4, 532.6 eV forM n ÀO, C=O, and CÀO bonds,r espectively, [21] indicative of residual oxygen-containing functional groups due to insufficient carbonization of agaric. The oxygen-containing residues maya ct as bridges joining the carbon matrix and MnO nanocrystals, which furtherf acilitate the utilization of active MnO species for electrochemical energy storage.…”

Ultrafine CoO Embedded Reduced Graphene Oxide Nanocomposites: A High Rate Anode for Li–Ion Battery

“…15 Graphene, a highly ordered porous material composing of sp 2 hybridized carbon atoms arranged in a honeycomb network, has recently been under limelight due to its intriguing mechanical and electric properties . The combination of graphene with metal oxides such as Fe 3 O 4 , SnO 2 , Co 3 O 4 , MnO, TiO 2 , CuO, MoO 2 and Co 3 O 4 has been reported as potential energy materials with high reversible capacities compared to their neat counterparts because the presence of graphene enhances the electrical conductivity to accelerate the transport of ions and electrons . Among the transition metal oxides used, cobalt oxide is one such material which has been under prime study because the theoretical capacity of CoO is around 716 mAh/g and the electrochemical reaction in the presence of Li ions appears to be completely reversible …”

Highly Reversible Lithium Storage of Nitrogen‐Doped Carbon@MnO Hierarchical Hollow Spheres as Advanced Anode Materials

“…[8] XPS characterization of NC@MnO HHSs confirms that the C 1s spectrum can well fit to six peaks at 284.3, 284.8, 285.5, 286.5, 288.0 and 289.3 eV, which correspond to C=C, CÀ C, CÀ N, CÀ OH, C=O and OÀ C=O components, respectively ( Figure 4f). [9][10][11]14,38] N 2 ad-/desorption measurements reveal that the special surface area of NC@MnO HHSs is about 55.4 m 2 g À 1 , and their corresponding pore volume is 0.079 cm 3 g À 1 ( Figure S4).…”

“…[10,11] Unfortunately, the practical implementation of MnO-based anode materials is still obstructed because of their short cyclic life and unsatisfactory rate performance, attributable to their low conductivity, large volume variation and self-aggregation of MnO during intense cycles. [12][13][14] To overcome the aforementioned obstacles of MnO-based materials, various strategies are rationally designed, such as nanosizing of MnO, [15][16][17] constructing novel nanostructures (hierarchical, hollow and yolk-shelled nanostructures) [18][19][20][21][22][23] and hybridizing of the nitrogen-doped carbon. [22][23][24][25][26] The first strategy is to design nanosized MnO particles to decrease the Li-ion/ electron transfer distance and partly buffer the volume variation during intensive cycles, advantageous to the enhancement of their rate capability and cyclic stability.…”