ABSTRACT
The construction of carbon-coated heterostructures of bimetallic sulfide is an effective technique to improve the electrochemical activity of anode materials in lithium-ion batteries. In this work, the carbon-coated heterostructured ZnS-FeS2 is prepared by a two-step hydrothermal method. The crystallinity and nature of carbon-coating are confirmed by the investigation of XRD and Raman spectroscopy techniques. The nanoparticle morphology of ZnS and plate-like morphology of FeS2 is established by TEM images. The chemical composition of heterostructure ZnS-FeS2@C is discovered by an XPS study. The CV results have disclosed the charge storage mechanism, which depends on the capacitive and diffusion process. The BET surface area (37.95 m2g-1) and lower Rct value (137 Ω) of ZnS-FeS2@C are beneficial to attain higher lithium-ion storage performance. It delivered a discharge capacity of 821 mAh g-1 in the 500th continuous cycle @ A g-1, with a coulombic efficiency of around 100%, which is higher than the ZnS-FeS2 heterostructure (512 mAh g-1). The proposed strategy can improve the electrochemical performance and stability of lithium-ion batteries, and can be helpful in finding highly effective anode materials for energy storage devices.
Subject(s)
Carbon , Lithium , Electrodes , SulfidesABSTRACT
The most pressing concerns in environmental remediation are the design and development of catalysts with benign, low-cost, and efficient photocatalytic activity. The present study effectively generated a flower-like indium oxide (In2O3-MF) catalyst employing a convenient MOF-based solvothermal self-assembly technique. The In2O3-MF photocatalyst exhibits a flower-like structure, according to morphology and structural analysis. The enhanced photocatalytic activity of the In2O3-MF catalyst for 4-nitrophenol (4-NP) and methylene blue (MB) is likely due to its unique 3D structure, which includes a large surface area (486.95 m2 g-1), a wide spectrum response, and the prevention of electron-hole recombination compared to In2O3-MR (indium oxide-micro rod) and In2O3-MD (indium oxide-micro disc). In the presence of NaBH4 and visible light, the catalytic performances of the In2O3-MF, In2O3-MR, and In2O3-MD catalysts for the reduction of 4-NP and MB degradation were investigated. Using In2O3-MF as a catalyst, we were able to achieve a 99.32 percent reduction of 4-NP in 20 min and 99.2 percent degradation of MB in 3 min. Interestingly, the conversion rates of catalytic 4-NP and MB were still larger than 95 and 96 percent after five consecutive cycles of catalytic tests, suggesting that the In2O3-MF catalyst has outstanding catalytic performance and a high reutilization rate.
Subject(s)
Environmental Restoration and Remediation , Metal-Organic Frameworks , Catalysis , Light , Methylene BlueABSTRACT
Numerous reports have elucidated the advantages of SiOx-based anodes including their large capacities and superior cycling stabilities. However, these electrodes have not been optimized for use in electric vehicles (EVs), which demand even better performance stability at fast charging rates and high temperatures. Herein, we fabricated a novel solid electrolyte interphase (SEI) using nanodiamondseeds. The grown SEI comprised an assembly of pillars, with a height and diameter of approximately 600 and 250 nm, respectively. As a result, the Li||Ti-SiOx@C cell with a nanodiamond-containing electrolyte achieved a high capacity retention of 76.4% over 1000 cycles at 5 A g-1 and 50 °C, whereas the cell with no nanodiamond seeds showed a severe decay in the capacity and retained only 61.5% of its initial capacity. Furthermore, the NCM811||Ti-SiOx@C full cell constructed with the pillar-type SEI also showed a high capacity retention of 61.8% at 5 C (1 C = 200 mAh g-1) and 50 °C after 500 cycles, which was a significant improvement from the value (33.3%) demonstrated by its counterpart comprising the conventional SEI. The results obtained herein will enable the development of high-performance lithium-ion batteries.
ABSTRACT
A Si-based anode maintaining its high electrochemical performance with cycles was prepared for the nondegradable lithium-ion battery. Nanoscaled Si particles were mechanochemically coupled with approximately 3 nm thick oxide layer and n-carbon (nanoscaled carbon) crystallites to overcome silicon's inherent problems of poor electronic conductivity and severe volume change during lithiation and delithiation cycling. The oxide layer of SiO x was chemically formed via a controlled oxygen environment during the process; meanwhile, the n-carbon crystallites were obtained by mechanical fragmentation from â¼70 µm sized multilayered graphene powders with a low degree of agglomeration. The Si-based composite anode, processed by the above-mentioned mechanochemical coupling, maintained a superior discharge capacity of 1767 mA h/g through 100 cycles with a Coulombic efficiency exceeding 98% at a current density of 100 mA/g. According to our current study, the coupling of the Si particles with oxide layer and n-carbon crystallites was found to be a significantly efficient way to prevent the performance degradation of the Si-based anode.
ABSTRACT
A SiO x coating material for Si anode in lithium-ion battery was processed by using SiCl4 and ethylene glycol. The produced SiO x particles after heat treatment at 725°C for 1 h were porous and irregularly shaped with amorphous structure. Pitch carbon added to SiO x was found to strongly affect solid electrolyte interphase stabilization and cyclic stability. When mixed with an optimal amount of 30 wt% pitch carbon, the SiO x showed a high charge/discharge cyclic stability of about 97% for the 2nd to the 50th cycle. The initial specific capacity of the SiO x was measured to be 1401 mAh/g. On the basis of the evaluation of the SiO x coating material, the process utilized in this study is considered an efficient method to produce SiO x with high performance in an economical way.
