Preparation And Study On Tin-based Oxide As Negative Material For Lithium Ion Batteries

Rechargeable lithium-ion battery has the best applying prospect in the battery market. The property of battery is decided greatly by choosing the suitable electrode materials, which should store enough lithium and have excellent reversibility of lithium intercalation/extraction in order to fulfill the cell performance of high energy density, high voltage and excellent cycle life. In commercial applications the graphite and other carbonaceous materials were widely used as negative electrode materials, however, these carbon-based anode materials have some self-blemish. To get better anode materials, a large number of alternative possibilities for anodes of lithium-ion batteries have recently been studied and reported in the literatures. Especially, the tin- based composite oxide has attracted special attentions in the research of anode materials for lithium-ion batteries.In this paper, the anode materials based on SnO₂ were synthesized using the Sol-Gel technique, and were characterized by X-ray diffraction (XRD),transmission electron microscope (TEM), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS).In the end, they were used as the anode material for lithium-ion batteries, and their electrochemical performance were studied in detail. Our work was shown as the following:1, SnO₂ particles of about 20³0nm with reuniting phenomena were prepared from SnCl₂·2H₂O as raw material by Sol-Gel technique. When it was used as the anode material for lithium-ion batteries, in the first cycle it shown discharge reversible capacity of 556.9 mAhï¹’g^-1, which also had a large irreversible capacity of 759.65 mAhï¹’g^-1, almost 57.7% of the first total charge capacity. The capacity reducing fast in the cycles showed the poor cyclability of the material.2, SnO₂ particles (²0nm) were synthesized by Sol-Gel technique and treatment with surfactants (PEG or CTAB). Reuniting phenomena of SnO₂ was decreased. The electrochemical properties of nano-sized SnO₂ powder as anode material for lithium ion batteries were studied. The first reversible capacity(more than 684.7 mAhï¹’g^-1) and cycle performance of dispersed SnO₂ was enhanced.3, To improve the electrochemical properties of SnO₂ material, prevent the aggregation of Sn particle during the cycling, here we chose kaolin to be the dispersant in the system. Here we found both the discharge capacity(more than741 mAhï¹’g^-1)and the cyclability of the SnO₂/kaolin composite obtained using the Sol-Gel technique were better than the pure SnO₂.4, SnO₂ material was modified with the doping of phosphomolybdic acid and the eradiating of microwave. The results indicated that the composite (～5nm) was obtained under following conditions: the dosage of phosphomolybdic acid is 0.015gï¹’g^-1, heat treatment with microwave. The electrochemical properties of nano-sized composite as anode material for lithium ion batteries were investigated. The composite possessed the advantages of higher reversible capacity and improved cycle performance.5, The modified composite was obtained by doping of La₂O₃ and Mn. In the first cycle, it shown charge capacity of 2025.1 mAhï¹’g^-1 and discharge capacity of 922.9 mAhï¹’g^-1.