Study of Sn-Coated Graphite as Anode Material for Secondary Lithium-Ion Batteries (original) (raw)
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Carbon, 2006
Electrochemical lithium insertion was carried out in tin-graphite composites obtained by two different preparation processes. In the first graphite was mixed with the products obtained by reduction of SnCl 4 with Na tert-Butanoate (t-BuONa)-activated NaH (two-step synthesis). The second used materials synthesized by reducing SnCl 4 with a graphite and (t-BuONa)-activated NaH suspension in THF (one-pot synthesis). Both composites were characterized by X-ray diffraction and transmission electron microscopy. It appeared that the tin particle size was controlled by the reduction time of SnCl 4. The stability of the electrochemical capacity of composites prepared by the two-step synthesis is dependent on the tin particle size: a stable capacity upon cycling was shown with subnanometer particles while a capacity fade was observed with larger nanoparticles. In materials prepared by the one pot synthesis, tin was present either as nanopartcles supported on graphite or as free aggregates. An initial reversible capacity of 630 mA hg À1 decayed to a constant value of 415 mA hg À1 after 12 charge/discharge cycles. It was hypothesized that the fraction of tin bound to graphite contributed to the stable reversible capacity while free tin aggregates were responsible for its decay.
Preparation of Encapsulated Sn-Cu@graphite Composite Anode Materials for Lithium-Ion Batteries
International Journal of Electrochemical Science, 2018
Electroless encapsulation of graphite particles with copper-tin alloy (Sn-Cu@graphite) is demonstrated as a feasible anode preparation method that is cost effective and provides both high cyclability and reversible capacity. Heat treatment of the electroless composites at 200 o C yielded Sn-Cu@graphite anode composites with a 20 wt.% Sn loading, specific surface area of 22.5 m 2 /g and a 1 st discharge capacity of 1074 mAh/g at 0.2C rate. In contrast, the graphite substrate particles used for the encapsulation has a surface area of 2.34 m 2 /g) and a 1 st cycle discharge capacity of 327 mAh/g at 0.2 C rate. At the 300 th cycle, these capacities decreased to ~400 mAh/g and 208 mAh/g for the SnCu@graphite and graphite substrate, respectively. Above 300 cycles, the electroless encapsulated SnCu@graphite anode maintained a capacity higher than that determined experimentally and theoretically for graphite. The electrochemical impedance and cyclic voltammetric results demonstrate that the...
Low-temperature behavior of graphite–tin composite anodes for Li-ion batteries
Journal of Power Sources, 2010
The challenge of increasing low-temperature performances of anodes for Li-ion batteries is faced by preparing graphite-tin composite electrodes. The anodes are prepared by mixing partially oxidized graphite with nanometric Sn powder or by coating the oxidized graphite electrode with a thin Sn layer. Long-term cycling stability and intercalation/deintercalation performances of the composite anodes in the temperature range 20 • C to −30 • C are evaluated. Kinetics is investigated by cyclic voltammetry and electrochemical impedance spectroscopy, in the attempt to explain the role of Sn in reducing the overall electrode polarization at low temperature. Two possible mechanisms of action for bulk metal powder and surface metal layer are proposed.
Chemical Physics Letters, 2018
SnO 2 /graphite oxide/g-C 3 N 4 composite was synthesized by hydrothermally growing SnO 2 nanosheets on graphite oxide/g-C 3 N 4 using tin dichloride and mercapto acetic acid as tin source and structure-directing agent for SnO 2 nanosheets, respectively. For comparison, SnO 2 /graphite oxide and SnO 2 /g-C 3 N 4 composites were prepared with the same procedure except different supports. The obtained composites were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric-differential thermal analysis and electrochemical properties. The results show that the SnO 2 /graphite oxide/g-C 3 N 4 composite with the graphite oxide/ g-C 3 N 4 support enhanced reversible capacity and cycling performance for lithium storage.
Advanced Materials, 2007
Lithium-ion batteries are the power sources of choice for popular mobile devices, such as cellular phones and lap-top computers. However, to meet the user's demands, the consumer electronics market is in continuous evolution with the production of diversified multifeature devices that require constantly increasing power levels. Therefore, it is expected that even the lithium-ion battery will soon become inadequate to meet the expectations of this fast-growing market. In addition to the consumer electronics area, high-energy batteries are also urgently needed to face the great challenges of the new millennium, namely a change of energy policy and a more accurate control of the environment of the planet. In response to these needs, which, among others, call for a wide use of clean-energy sources and for the large-scale introduction of controlled-or zero-emission vehicles, it is now essential that high-energy, low-cost, and environmentally friendly storage systems are identified. Lithium batteries could still be the best candidates for all these applications, provided that their performance reaches a level higher than that presently offered.
Preparation and Characterization of Tin/Carbon Composites for Lithium-Ion Cells
MRS Proceedings
A number of Sn/C composites were prepared for evaluation as anode materials for Li-ion cells. In one case, samples were prepared by incorporation of Sn species into organic precursors that were then pyrolyzed under an Ar/H2 cover gas to prepare the Sn/C composites. They were also prepared by decoration of various types of carbon with nanoparticles of Sn by electroless deposition using hydrazine. The carbons examined included a disordered carbon prepared in house from poly(methacrylonitrile), a mesocarbon microbead (MCMB) carbon, and a platelet graphite. The Sn/C composites were examined by x-ray diffraction (XRD) and scanning electron microscopy (SEM) and were also analyzed for Sn content. They were then tested as anodes in three-electrode cells against Li metal using 1M LiPF6 in ethylene carbonate (EC)/dimethyl carbonate (DMC) solution. The best overall electrochemical performance was obtained with a Sn/C composite made by electroless deposition of 10% Sn onto platelet graphite.
Carbon-based anode materials for lithium-ion batteries
Lithium-Sulfur Batteries
Physical characterisation of tin-graphite composites 6.3.2 Electrochemical measurement of Sn-graphite composite electrodes 6.4 Conclusions CHAPTER 7. ELECTROCHEMICAL CHARACTERISTICS OF TIN-COATED MCMB GRAPHITE AS ANODE IN LITHIUM-ION CELLS 7.1 Introduction 7.2 Experimental 7.3 Results and discussion 7.4 Conclusion CHAPTER 8. GENERAL CONCLUSIONS
Nanomaterials, 2013
Tin-oxide and graphene (TG) composites were fabricated using the Electrostatic Spray Deposition (ESD) technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.
Journal of Power Sources, 2015
The electrodeposited Sn-O-C composite anode cycling with LiClO 4 delivered stable cycle performances showing discharge capacity of 473 mAh g of Sn-1 with 95 % of coulombic efficiency at 100th cycle. However, the anode showed poor cycle performances with LiPF 6 delivering discharge capacity of 69 mAh g of Sn-1 at 100th cycle with 70 % of coulombic efficiency. Electrochemical investigation performed by cyclic voltammetry and differential capacity plots revealed that the Sn-O-C composite cycling with LiPF 6 suffered from retarded phase transition reaction between Li and Sn during charge/discharge process. X-ray photoelectron spectroscopy declared the existence of fluorinated-Sn and LiF. Moreover, energy dispersive X-ray spectroscopy found increase in their amount with repeated cycles. The morphologies of the Sn-O-C composite cycled with LiPF 6 showed aggregated particles containing the chemical state of fluorinated-Sn and LiF on its surface. Furthermore, the significant pulverization and aggregation of the active material were observed from the Sn-O-C composite cycled by LiPF 6 rather than that of LiClO 4 , which was probably promoted by the generated HF strongly corroding metallic component.