In Situ Synthesis of 1D Mesoporous MnO@C Nanorods for High Performance Li-Ion Batteries

Abstract

Transition metal oxides have been regarded as the most potential anode material for lithium-ion batteries (LIBs), because of their high theoretical capacity, abundant resource, and low cost. Nevertheless, poor conductivity and large volumetric expansion during the charge–discharge processes make it difficult for LIBs application. In this work, we have adopted an in situ carbon coating method to synthesize 1D mesoporous MnO@C nanorods, which effectively work out the above problems of LIBs. Meanwhile, the MnO@C-3 (the mixture is 40 mL of H2O in solvothermal reaction) anode exhibits excellent rate capability with the capacity retention of 90.3% at 2.0 A g–1 and prominent cycling stability at 5.0 A g–1 with the discharge capacity of 1210.1 mAh g–1 after 400 cycles. When assembled to a full cell with commercial LiFePO4 as cathode, the full cell represents 360.7 mAh g–1 after 30 cycles (based on the anode), which displays a development potential for practical application.

Effects of Carbon Content and Current Density on the Li+ Storage Performance for MnO@C Nanocomposite Derived from Mn-Based Complexes

“…These weak peaks would disappear during the subsequent cycles, indicating the irreversible formation of SEI film [ 29 ]. The sharp peak below 0.1 V could be attributed to the reduction of MnO to metallic Mn (MnO + 2Li + + 2e + → Mn + Li 2 O) [ 30 ]. In the subsequent cycles, the reduction peak slightly moved to 0.38 V, which could be assigned to the activation process [ 31 ].…”

Silver‐Catalyzed Hydrogenation of Ketones under Mild Conditions

“…In those cases, the products were isolated by a simple filtration on a short plug of silica. As shown in Table 2, sterically hindered ketones and both electron-withdrawing as well as electron-donating substituted aromatic ketones were hydrogenated in high yields (entries [1][2][3][4][5][6][7][8][9][10][11][12][13][14]. Under the standard reaction conditions, p-acetylacetophenone 1 o was partially hydrogenated furnishing the mono-reduced ketone 2 o in 92% yield ( Table 2, entry 15).…”

“…The unambiguous formation of nanoparticles raises the issue of stabilizers in general necessary to prevent extensive agregation of nanoparticles. Considering that hydrogenation reactions promoted by metal-nanoparticles do not require a base, [5,[7][8][9]13] we believe that the bulky potassium hexamethyldisilazide initially introduced as a base necessary for hydrogen activation in an homogeneous catalytic reaction may play the role of stabilizing agent via electrostatic and/or electrosteric effects which are known processes for metal nanoparticle stabilization. [14] Conclusion In summary, the unprecedented hydrogenation of ketones with a silver catalyst is reported.…”

“…The corresponding alcohols were obtained in moderate to high yield at 100 8C and 40 bar of hydrogen pressure in water. [7] In 2009, De Vos reported polymer stabilized AgÀNPs that reduced a number of unsaturated ketones with moderate to high selectivity at 60 8C and 40 bar of hydrogen pressure. [8] More recently, Moores described the use of plasmonic silver nanocubes for the hydrogenation of ketones and aldehydes.…”

1D Core‐shell MnO@S, N co‐Doped Carbon for High Performance Lithium Ion Battery Anodes

“…Currently, there are mainly three strategies to address the above‐mentioned issues, including adjusting the morphology and particle size to shorten the diffusion distance and increase the contact area between electrode and electrolyte, coating carbon or heteroatom‐doped carbon to produce core‐shell structure to alleviate the volume change, and hybridizing with other TMOs to form bicomponent‐active MnO‐based material to enhance the electrical conductivity . Particularly, heteroatom‐doped carbon coating is a more efficient method, due to the provision of high conductivity, which is beneficial to achieving fast lithiation/delithiation reactions and enhancing the electrochemical oxidation kinetics of Mn 2+ to higher oxidation state, and therefore promoting the improvement of lithium storage performance.…”