Core-leaf onion-like carbon/MnO2 hybrid nano-urchins for rechargeable lithium-ion batteries

Abstract

A hybrid nano-urchin structure consisting of spherical onion-like carbon and MnO2 nanosheets is synthesized by a facile and environmentally-friendly hydrothermal method. Lithium-ion batteries incorporating the hybrid nano-urchin anode exhibit reversible lithium storage with superior specific capacity, enhanced rate capability, stable cycling performance, and nearly 100% Coulombic efficiency. These results demonstrate the effectiveness of designing hybrid nano-architectures with uniform and isotropic structure, high loading of electrochemically-active materials, and good conductivity for the dramatic improvement of lithium storage. Disciplines Engineering | Physical Sciences and Mathematics Publication DetailsWang, Y., Han, Z., Yu, S., Song, R., Song, H., Ostrikov, K. & Yang, H. (2013). Core-leaf onion-like carbon/ MnO2 hybrid nano-urchins for rechargeable lithium-ion batteries. Carbon, 64 (November), [230][231][232][233][234][235][236] This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. IntroductionDeveloping high-performance rechargeable lithium-ion batteries (LIBs) is among the most promising solutions to address the drastic increase in global demand of energy [1]. LIBs were introduced to the market in the 1990s by Sony and soon attracted a strong research interest due to their high energy density, stability, and no memory effect, as compared to other alternatives [2]. However, commercial LIBs mostly use graphite as the anode material, which possesses a relatively low theoretical specific capacity of ~372 mAh g -1 . This low capacity severely hampers the wide usage of LIBs in the surging consumer electronic devices and the large-scale energy applications such as hybrid electric vehicles, renewable power plants, and load levelling [3][4][5]. To accommodate the high-level requirements of these advanced applications, it is imperative to explore new electrode materials and novel designs for higher energy density, lower cost, flexibility, non-toxicity, and better stability.The recent advances in nanotechnology have offered a promising route to tackle these challenges [6][7][8][9]. As compared to the bulk materials, nanostructured materials possess a large surface area with excellent electrical, optical, and mechanical properties. Nanomaterials can enhance the performance of LIBs through two approaches. The first one is by using lowdimensional carbon-based nanomaterials to provide more efficient lithiation and delithiation In this work we solve these problems by fabricating the hybrid nano-urchin structure consisting of onion-like carbon/MnO 2 (OLC/MnO 2 ) using a simple and environmentallybenign hydro...

Superior Lithium Storage Performance using Sequentially Stacked MnO2/Reduced Graphene Oxide Composite Electrodes

“…The plateau at 0.75 V disappeared and the one at 0.48 V was shortened in subsequent discharge cycles, which confirm the formation of a metallic manganese and lithium oxide matrix. [22,[35][36][37] This discharging/charging behavior was consistent with each other, as shown in Figure 7, and the MnO 2 /rGO composite was superior to that of the pure MnO 2 and MnO 2 / graphene electrodes. The specific capacity of pristine MnO 2 was 1573 mA h g À1 in the first discharge cycle, which was substantially larger than the theoretical value (1230 mA h g…”

MnOx/carbon nanotube/reduced graphene oxide nanohybrids as high-performance supercapacitor electrodes

“…Specifically, the porous and flower-like structure could provide a large and accessible surface area to greatly enhance surface ion adsorption, improve the accessibility of cations and shorten the ion diffusion path. 2,17 The smaller and uniformly sized nanoparticles could also facilitate fast charge transfer on the surface or sub-surface of the active material; for example, Duay et al 12 found that the specific capacitance was much higher for small MnO 2 nanofibrils (5-10 nm) than for large MnO 2 nanowires (4.5 μm). In addition, although MnO x could be gradually oxidized to a higher valent state during the charge/discharge process, the structural features associated with the as-prepared MnO x , such as ionic (e.g., vacancies and misplaced ions) and electronic (electrons and holes) defects and mismatches at different phases, could still be preserved because of the slow and mild nature of the process.…”

“…13 However, despite a few examples of MnO x reported recently, 14 most previous studies simply denoted the synthesized Mn oxides as MnO 2 with few or no structural investigations. [15][16][17] The integration of MnO x into supercapacitor electrodes with binders is also challenging because of the non-uniform particle size, poor electrical conductivity and structural instability of MnO x . In addition, MnO x was mainly synthesized by methods involving hazardous chemicals, strong acids and high-temperature thermal annealing, with the controllability, scalability and reliability of these methods remaining unclear.…”

MoS2-coated vertical graphene nanosheet for high-performance rechargeable lithium-ion batteries and hydrogen production

“…An equivalent circuit model was used to simulate the electrical components (inset of Supplementary Figure S11), where R s represents the current collector and electrolyte resistance; R f and CPE 1 are the SEI layer resistance and the constant-phase element (CPE), respectively; R ct and CPE 2 are the charge transfer resistance and double-layer capacitor, respectively; and W is the Warburg impedance related to lithium diffusion. 37 The fitting results were summarized in Supplementary Table S2, which clearly shows that the charge transfer resistance of the MoS 2 /VGNS electrode was significantly increased from 28.73 to 228.27 Ω when the amount of Mo salt precursor was increased from 3 to 22 mg. The highest charge transfer resistance was observed on the MoS 2 /CB control sample, indicating the poor electrical conductivity of the system.…”