Lamellarly Stacking Porous N, P Co‐Doped Mo₂C/C Nanosheets as High Performance Anode for Lithium‐Ion Batteries

Abstract

time-consuming, entailing hazardous chemicals or harsh fabrication conditions, and not universal for large-scale application. [4] For example, Hu and co-workers used phosphomolybdic acid (PMo) to initiate the polymerization of polypyrrole for 12 h, which was then subjected to an annealing process to finally obtain the pomegranatelike N, P-doped Mo 2 C@C nanospheres. [3g] The poisonous nature of the pyrrole monomer reactant and the prolonged polymerization process limits practical applications of this method. Besides, ions exchange resin was used to absorb the molybdenum source for more than 20 h, and the composite was then annealed to give rise to Mo 2 C nanoparticles wrapped in the carbon matrix. [5] The adsorptive process is really time-consuming and the utilization of the molybdenum salts is extremely low. As a result, it remains a great challenge to directly and controllably synthesize highly efficient TMC-based electrodes for lithium-ion batteries.Moreover, in view of large volume change of TMCs during the repeating lithiation/delithiation process, porous structure with sufficient void space had been considered as an effective path to mitigate the strike of volume expansion. Previous reports show that interconnected porous nanosheets, arranging into highly separated and permeable porous networks, have Layered stacking and highly porous N, P co-doped Mo 2 C/C nanosheets are prepared from a stable Mo-enhanced hydrogel. The hydrogel is formed through the ultrafast cross-linking of phosphomolybdic acid and chitosan. During the reduction of the composite hydrogel framework under inert gas protection, highly porous N and P co-doped carbon nanosheets are produced with the in situ formation of ultrafine Mo 2 C nanoparticles highly distributed throughout the nanosheets which are entangled via a hierarchical lamellar infrastructure. This unique architecture of the N, P co-doped Mo 2 C/C nanosheets tremendously promote the electrochemical activity and operate stability with high specific capacity and extremely stable cycling. In particular, this versatile synthetic strategy can also be extended to other polyoxometalate (such as phosphotungstic acid) to provide greater opportunities for the controlled fabrication of novel hierarchical nanostructures for next-generation high performance energy storage applications.

SnO2@MoO2/Carbon Ternary Hollow Nanocomposites with Robust Shell as High‐Performance Lithium‐Ion‐Battery Anodes

“…[31,52] Meanwhile, compared with MoCSs and SnCHNs, the steeper line of SnMoCHNs in the low frequency range reveals their smaller impedance value of Li + diffusion, which facilitates Li + insertion/extraction. [16,24,53] SnMoCHNs have a smaller diffusion impedance, which stems from the larger specific surface area and pore volume compared with the other two samples.…”

“…[35,43,45] In Figure 4d, the two peaks at 230.2 and 233.2 eV with the energy separation of 3.0 eV correspond to Mo3d 5/2 and Mo3d 3/2 states of Mo 4 + , while the peaks at 235.9 eV and 232.3 eV correspond to Mo 6 + , which may be caused by the partial oxidation of MoO 2 . [16,[46][47][48] In the O 1s spectrum ( Figure S7), the peaks at 530.8 eV and 530.2 eV correspond to MoÀ O and SnÀ O bonds, respectively. The peaks at 532.1 eV and 533.0 eV may be due to the formation of CÀ OÀ Mo bond and C=O bond.…”

Hierarchical Porous Molybdenum Carbide Based Nanomaterials for Electrocatalytic Hydrogen Production

“…Nitrogen-doped nano-carbon support plays an important role in improving electrocatalytic activity (Wu et al, 2018a;Lyu et al, 2019). Wu et al (2016) synthesized ultrafine Mo 2 C nanoparticles embedded within bacterial cellulose-derived 3D Ndoped carbon nanofiber networks (Mo 2 C@N-CNFs).…”

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

“…[1][2][3] However, to meet the increasing requirements for the ever-advancing power sources, the further development of high-performance and low-cost anode materials with novel nanostructures in LIBs is of significant importance. [4][5][6][7] Amongst metal oxides (MOs) as anode materials in LIBs, manganese monoxide (MnO) has attracted considerable attention because of its low cost, low working potential, [8,9] natural abundance, high theoretical capacity (756 mAh g À 1 ) and environmental benignity. [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.…”

“…As optimal power sources, Li‐ion batteries (LIBs) have been extensively applied in the rapidly growing electrical vehicles and electronics . However, to meet the increasing requirements for the ever‐advancing power sources, the further development of high‐performance and low‐cost anode materials with novel nanostructures in LIBs is of significant importance . Amongst metal oxides (MOs) as anode materials in LIBs, manganese monoxide (MnO) has attracted considerable attention because of its low cost, low working potential, natural abundance, high theoretical capacity (756 mAh g −1 ) and environmental benignity .…”