Npg asia materials – tuning ultrafine manganese oxide nanowire synthesis seeded by si particles and its superior li storage behaviors

One-dimensional (1D) nanostructures with a high surface-to-volume ratio and potential for quantum confinement have attracted the attention of materials scientists in recent years. F gas regulations 1, 2, 3, 4 MnO is among the well-known technologically important materials used in diverse application areas, including in electronics, 5 sensors, 6 magnetic storage media, 7 optical 8 and catalysis, 9 especially lithium-ion batteries. Z gas cd juarez telefono 10, 11, 12, 13, 14, 15, 16, 17, 18 Several techniques for the synthesis of MnO 1D structures have been made available. Astrid y gaston lima menu prices Guo and co-workers 11 designed an MnO /carbon nanopeapod nanostructure with an internal void space by annealing the MnO precursor /polydopamine core /shell nanostructure. Gas under a dollar This anode material exhibits a high reversible capacity. Find a gas station near me Huang and co-workers 12 proposed N-doped carbon webs to support MnO nanoparticles, which also exhibit great electrochemical performance. Electricity number It has been demonstrated that decreasing the size of MnO particles to the nanoscale can mitigate the physical strains during the Li uptake /release process, so that the volume change causes less cracking and particle pulverization. Electricity quiz 4th grade However, to the best of our knowledge, there are fewer reports about the controllable synthesis of ultrafine MnO nanowire-seeded particles. V gas llc Since the performance and function of nanowires can be deliberately tuned through size- and shape-dependent effects, the development of reliable and controlled syntheses for 1D nanostructures is necessary.

Herein, we report a novel approach that utilizes Si nanoparticles for synthesizing ultrafine MnO nanowires with ~5–10 nm in diameter. Gas finder near me X-ray diffraction (XRD) patterns and high-resolution transmission electron microscopy (HRTEM) images clearly reveal the growth mechanism of MnO nanowires. Rahal e gas card As an anode material for the lithium-ion battery, the MnO nanowires exhibit an excellent charge transfer kinetics performance. Gas dryer vs electric dryer calculator This synthesis strategy may inspire studies of other TMO nanomaterials with special orientation to tune their physical chemistry properties.

Equations (1) and (2) occur simultaneously. Electricity production in usa It is noteworthy that product MnCO 3 can not only be formed separately but also could be generated on the surface of the Mn 7SiO 12 by lattice match. Gas variables pogil answers To figure out the mechanism of MnCO 3 nanowire growth, the morphology of the products for different Mn /Si molar ratios was characterized by TEM, as shown in Figure 2. Gas x coupon 2014 It can be found that the Mn /Si ratio is a crucial factor affecting the morphology of the as-obtained products. Gas zyklon b The pristine Si nanoparticles are sphere-like particles ~100 nm in diameter ( Supplementary Figure S3). Gas tax in washington state When the Mn /Si molar ratio is 16:1, no Si phase was observed, and the products comprise MnCO 3 and Mn 7SiO 12. Electricity youtube The amount of Mn 7SiO 12 is very small so that there are not enough sites for the growth of MnCO 3 nanowires on the surface of Mn 7SiO 12 by lattice match. Gas outage That means MnCO 3 particles are mainly formed alone. Gas in oil briggs and stratton engine Therefore, the morphology of the as-obtained products features an agglomerate of nanoparticles that are several nanometers in diameter ( Figure 2a). Gas near me When the Mn /Si molar ratio is 8:1 ( Figure 2b), the phase composition and product morphology do not change, remaining as an agglomerate of sphere particles. Electricity receiver When this ratio is changed to 4:1 ( Figure 2c), the balance between the forming rate of MnCO 3 and the amount of sites for the growth of MnCO 3 on the surface of Mn 7SiO 12 may be suitable for the growth of MnCO 3 nanowires by lattice match. F gas logo As a result, ultrafine MnCO 3 nanowires less than 10 nm in diameter are obtained. Que gases componen el aire The resultant MnCO 3 nanowires disperse uniformly and are interconnected. La gas Increasing the Mn /Si molar ratio up to 2:1 ( Figure 2d), there are so many sites for the growth of MnCO 3 on the surface of Mn 7SiO 12 that the amount of KMnO 4 may not meet for the continuous growth of nanowires. Gas news uk Therefore, MnCO 3 demonstrates irregular morphology around the Mn 7SiO 12 particles.

Previous works reported that heterogeneous nanostructure materials can be synthesized by the epitaxial growth of different crystals. Static electricity bill nye full episode 22, 23 If the lattice mismatches are sufficiently small, the epitaxial growth is tolerated and the heterogeneous 1D nanostructure can be formed. All 4 gas giants names Based on the XRD data, the lattice mismatches ( Supplementary Figure S4) between (104), (110), (113) planes of standard MnCO 3 and (125), (040), (332) planes of standard Mn 7SiO 12 are almost 0 %. E electricity bill payment From Figures 2e and f, the lattice planes of the MnCO 3 nanowires are determined to be (104), while those of the Mn 7SiO 12 particles are assigned to be (125). Static electricity examples The lattice match between the (104) planes of MnCO 3 nanowires and the (125) planes of Mn 7SiO 12 particles is good. Electricity physics ppt Consequently, MnCO 3 can easily grow on the Mn 7SiO 12 nanomaterial to become 1D nanowires. B games virus Figure 3 compared the TEM images of the MnCO 3 nanowires at different reaction times. Gas bubble in throat KMnO 4 first reacted with the Si nanoparticles to form small Mn 7SiO 12 particles with rough surfaces in the initial stage ( Figure 3a). Gas vs electric oven running cost After the Si nanoparticles were consumed, the growth of Mn 7SiO 12 stopped, and MnCO 3 nanowires gradually formed on the surface of the Mn 7SiO 12 owing to the lattice match and the appropriate Mn /Si molar ratio ( Figure 3b). Gas mask bong how to use It was found that the MnCO 3 nanowire continued to grow longer and wider for 12 h after the reaction ( Figure 3c). Hp gas online booking no When the hydrothermal reaction time was increased, the diameter of the MnCO 3 nanowire started to shrink, which is attributed to the aging of the Mn 7SiO 12 ( Figures 3d and e). Gas 2 chainz After a 24 h reaction, the presence of the Mn 7SiO 12 nanoparticles and MnCO 3 nanowire was observed in the final product ( Figure 3e). O gastroenterologista cuida do que The Mn, Si and O elements in the Mn 7SiO 12 particles were confirmed by energy-dispersive spectrometry ( Figure 3f). Electricity review worksheet Because of the weight difference between the big Mn 7SiO 12 particles and MnCO 3 nanowires, the MnCO 3 nanowire can be easily separated by centrifugation, similar to the Evans’work. Gas jobs pittsburgh 24 After separation, no obvious signal of Si element can be found from the energy-dispersive spectrometry result. Electricity invented what year Combined with the XRD results above, it can be concluded that the product is mainly composed of MnCO 3 nanowires. Gas after eating red meat According to our knowledge, this is the first report about the epitaxial growth of compounds.

The MnO@C nanowire composites were synthesized via polymerization–pyrolysis steps (see Materials and methods for more details). Gas natural inc The typical XRD pattern of the MnO@C nanowires is presented in Figure 4a. Gas exchange in the lungs occurs due to All the diffraction peaks could be readily assigned to a pure cubic phase of MnO (JCPDS no. La gas leak 07-0230), 25 and no other impurity phases are detected. Wd gaster website Significantly, the broadening peaks indicate the ultrafine structure of the MnO nanowires, which inhibits its pulverization and facilitates the diffusion of lithium ions. Gas zombies black ops 11 The SEM and TEM images in Figures 4b and c show that the as-prepared MnO@C composites are nanowire-like and have crossed connections with each other. Gas bloating back pain The MnO nanowires are finely confined by the carbon framework, as shown in the HRTEM image of Figure 4d. Electricity transformer health risks This HRTEM image also reveals that crystalline MnO nanowires were embedded in the matrix of an amorphous carbon. Electricity words The lattice fringes with interplanar distances of 0.266 and 0.161 nm can be assigned to the (111) and (220) planes of MnO, respectively. Gas definition science The pyrolysis carbonaceous matrix acts as not only a volume buffer but also a conductive network when the composite of MnO and matrix is used as anode material in the LIBs during the charge–discharge process. 1 unit electricity cost in tamilnadu 10, 11, 12, 25, 26 Moreover, a thermogravimetry analysis was performed to further illustrate the carbon content of the composite ( Supplementary Figure S5). Electricity trading jobs The first weight loss was ~1.4 % and occurred below 200 °C, which can be attributed to the desorption of absorbed water. La gas prices average The second weight loss of ~12.1 % occurred from 200 to 900 °C and was due to the integrative effect of the combustion of the N-doping carbon and oxygenation of the MnO to Mn 2O 3. Electricity trading hedge funds 10 Therefore, the amount of MnO and amorphous carbon in the MnO@C nanowire can be calculated as ~74.9 and 25.1 %, respectively.

Figure 7 shows the charge and discharge profiles of a sample obtained at different current densities and indicates that MnO@C nanowires can be ultra-rapidly charged and discharged. V gashi 2013 The specific discharge capacities are 704.9, 646.4, 620.5, 601.8 and 543.8 mA h g −1 at current rates of 1, 2, 3, 4 and 5 A g −1, respectively, indicating a truly outstanding rate performance. Electricity billy elliot broadway The apparent diffusion coefficient was determined by a Randles-Sevcik analysis 30, 31 of cyclic voltammogram measurements at different scan rates to be 3.21 × 10 −8 cm 2 s −1 for the MnO@C during the discharge process ( Supplementary Figure S8). Electricity definition science The high apparent diffusion coefficient at room temperature explains the absence of substantial diffusional polarization, even at 5 A g −1. Electricity resistance questions After charge–discharge at a high rate (30 A g −1), the capacity can still reach its initial value (957.8 mA h g −1) at 0.2 A g −1, implying an excellent capacity retention. Z gas el salvador To the best of our knowledge, this high-rate behavior is unprecedented among other reports on MnO. Electricity symbols and units For this comparison, we selected the very best reports in the literature. B games car 10, 11, 12, 13, 14, 15, 16, 17, 18, 22 Considering the ultrafine diameter of MnO and the flexible nature of amorphous carbon with its protective effect as a matrix, this indicates that such an outstanding nanostructure can indeed relieve the strain and stress caused by volume variation in MnO nanowires. Electricity sources in canada Moreover, we also synthesized the MnO@C nanocomposite containing 6 % amorphous carbon by reducing the amount of phthalocyanine from 1 mmol to 0.75 mmol, as shown in Supplementary Figure S9a. Gas zone All the diffraction peaks shown in Supplementary Figure S9b could be assigned to a pure cubic phase of MnO (JCPDS no. V gashi 2015 07-0230). Gas ark However, calculated by the Scherrer equation, the average diameter of the MnO is larger than that of MnO@C nanomaterials containing 25.1 % amorphous carbon. Pictures electricity pylons The SEM and TEM images ( Supplementary Figures S9c and d) also demonstrate an irregular particle morphology. Electricity outage houston tx This may be because less carbon cannot prevent the aggregation of MnO nanowires in the pyrolysis process. O gastronomo buffet The obtained MnO@C nanocomposite containing 6 % amorphous carbon can deliver 635.5 mA h g −1 at a current density of 0.2 A g −1 after 50 cycles, and 246 mA h g −1 at a current density of 1 A g −1 after 200 cycles, as shown in Supplementary Figures S9e and f. Electricity for refrigeration heating and air conditioning 9th edition pdf In comparison with the nanowires MnO@C composite containing 25.1 % carbon, the decrease of capacity of the MnO@C nanocomposite containing 6 % amorphous carbon, especially for the rate capacity, is mainly related to the increase of irregular MnO particle size.

The excellent high-rate performance and stability of the MnO@C nanowires are attributed to the unique interconnected nanostructure, resulting from a high contact area between the electrolyte and electrode, as well as a bridge for electron transfer between carbon matrixes, leading to enhanced electrical conductivity. Gas dryer vs electric dryer hookups When the current density is increased to 1 A g −1, the initial reversible capacity of the composite is ~500.2 mA h g −1 and then grows slowly with repeated cycles, until the ~300th cycle. Electricity laws in india Subsequently, the specific capacity of the composite stabilizes gradually and reaches 757.4 mA h g −1 (about 100 mAh cm −3) after 1000 discharge /charge cycles ( Figure 8a). Ortega y gasset revolt of the masses This phenomenon of the gradual increase is also commonly observed in other TMO anodes and can largely be ascribed to the formation of high-oxidation state products or the redistribution of MnO material. Z gas cd juarez 15, 32, 33, 34 In the present work, we measured the ex situ Mn K-edge XAS spectrum for the MnO@C electrode after 500 cycles ( Figure 8b). Gas smoker recipes The spectrum of the sample presents three significant features: the pre-edge peak A, peak B and main peak C. Grade 6 science electricity unit test Peak A represents the 1s to 3d transition, which is normally forbidden and can only be allowed due to the hybridization of the p and d orbits. Electricity flows through Peak B can be asigned to the continuum threshold of core transitions to dipole-allowed p-like states of t1 symmetry. Electricity hair stand up The main absorption edge features, peak C, were attributed to the purely dipole-allowed 1s to 4p transition. Bp gas prices columbus ohio Using the ‘fingerprint’ of the Mn K-edge XAS, we can easily exclude the possibility of MnO 2. Electricity kwh usage calculator 35, 36 A small positive shift of the absorption edge compared with pristine MnO@C could be related to the pulverization of the MnO during the charge /discharge process. Gas examples 37 The radial-structure functions of the Mn K-edge ( Figure 8c) demonstrate the obvious increase in the peak height at 1.5 angstroms, implying an increase in the ordering of the O 2− ions in the MnO structure, which induces the fast diffusion of Li ions and a low internal resistance. Gas vs electric range 38 As for the change in the radial distribution function of the second shell of the MnO@C nanowire, it may be consistent with the increase in the disorder degree of the Mn–Mn shell corresponding to the coordination of the second shell, which was supported by the increases of Debye–Waller factor of Mn–Mn.

An electrochemical impedance spectroscopy analysis was performed to further investigate the charge-transfer resistance of the pure MnO nanoparticle and MnO@C nanowires electrode. Electricity 4th grade This revealed that the MnO@C nanowires electrode yields a far lower resistance than the pure MnO nanoparticle ( Supplementary Figure S10a). La gasolina lyrics These differences not only confirm the rational structure but also demonstrate the improved Li-reaction kinetics of the MnO@C nanowires composite. I gas shares 39 We also found that the charge-transfer resistance decreases with repeated cycles ( Supplementary Figure S10b), which is ascribed to the MnO@C nanowires composite structure and its activation process. Chapter 7 electricity note taking worksheet 40 Such unique results indicate better contact between the active material and electrolyte, improved conversion reaction kinetics and a higher reaction area of the MnO@C nanowires composite. Gas jet compressor Thus, it is reasonable that the MnO@C nanowires composite exhibited a relatively higher capacity and an excellent rate capability.

In summary, MnCO 3 nanowires were synthesized by an epitaxial growth mechanism under simple hydrothermal conditions. Static electricity in the body The Mn /Si molar ratio is the key parameter in the nanowire fabrication. Gas and electric credit union MnO nanowires approximately 5–10 nm in diameter were obtained through a facile polymerization–pyrolysis process. Gas works park events The rationally designed MnO@C nanocomposite exhibited excellent charge transfer kinetics and an extremely high electrochemical performance compared with graphite, including stable specific capacities of 285.9 mA h g −1 at 30 A g −1 and 757.4 mA h g −1 at 1 A g −1 after 1000 cycles. Grade 6 electricity project ideas Moreover, considering its simplicity and the new nanowire growth mechanism, this strategy may inspire studies of other TMO nanomaterials with special orientation to improve their physical chemistry properties.