Preparation method of stannic oxide or metallic tin and grapheme lamella composite material

Abstract

The invention provides a preparation method of a stannic oxide and grapheme lamella composite material. The preparation method comprises the following steps of mixing at least one organic solvents, graphene oxide lamella hydrosol and at least one tin salt, heating the mixture at a temperature of 60 to 200 DEG C for 0.5 to 12 hours to obtain a solid substance, and heating the solid substance in the inert gas atmosphere at a temperature of 400 to 700 DEG C for 0.5 to 10 hours. The invention also provides a preparation method of a metallic tin and grapheme lamella composite material. The preparation method comprises the following step of preparing a stannic oxide and grapheme lamella composite material through the preparation method of a stannic oxide and grapheme lamella composite material, and heating the prepared stannic oxide and grapheme lamella composite material in the reducing gas atmosphere at a temperature of 400 to 1000 DEG C for 0.5 to 4 hours. The preparation methods of the invention can improve a structural stability and an electrochemical performance of a material and is beneficial to improve a high-speed charging and discharging performance and a conductivity of a composite material. The preparation methods have the characteristics of cheap and easily available raw materials, simple process, and good applicability for industrial continuous production.

Description

Technical field [0001] The invention relates to a preparation method of tin dioxide or metal tin and graphene sheet-layer composite material. Background technique [0002] Metal tin and tin dioxide are potential anode materials for lithium-ion batteries. The theoretical capacities of the two have reached 990mAh / g and 781mAh / g, respectively. However, metal tin and tin dioxide will be produced during charging and discharging of lithium The large volume change (J. Electrochem. Soc., 1997, 144: 2045) causes poor cycle performance and low service life of the battery. At present, one of the main ways to solve this problem is to optimize the structure and composition of electrode materials by introducing active or inactive substances. When nano-active substances are uniformly dispersed in a certain conductive matrix material, the matrix material or alloy structure can be effective It prevents the agglomeration of active materials, and at the same time can be used as a buffer layer for ...

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Problems solved by technology

CN1812167A discloses a preparation method of a lithium ion battery negative electrode material composited with tin dioxide and graphite material, but due to the small specific surface area of ​​graphite, the negative electrode material cannot be fully contacted with the electrolyte, which affects the rapid charge and discharge performance of the electrode material

CN101478043A discloses a kind of graphene nano sheet loaded tin dioxide as the preparation method of lithium-ion battery negative electrode material, reversible specific capacity remains on more than 600mAh / g when charging and discharging with the electric current of 300mA / g, and GuoxiuWang etc. (J.Mater. Chem., 2009, 19, 8378-8384) using NaHB 4 The Sn / Graphene composites prepared by reducing agents used as lithium-ion battery electrode materials also have high reversible capacity, but these methods use strong reducing agents such as hydrazine hydrate, NaHB 4 etc. Such strong reducing agents will affect the formation process of tin dioxide particles and the recombination with graphene sheets, thereby affecting the electrochemical performance of electrode materials

However, most of these methods are simply mechanically mixing metal tin particles and carbon precursor substances. The obtained sample material is only filled with metal tin particles in the porous skeleton formed by the carbon matrix, and it is difficult to control the shape of the product during the pyrolysis process. appearance

CN101202340A discloses a kind of preparation method of tin-carbon nanocomposite material for negative electrode of lithium ion battery, but this method adopts starch as carbon source, and the amorphous carbon after high-temperature carbonization can not form good coating structure to metal tin particle, causes negative electrode material Low capacity, poor cycle performance

Recent studies (Nano Letters, 2008, 8, (8), 2277-2282) show that graphene sheets (Graphene Nanosheets, GNS) have high reversible capacity as lithium-ion battery electrode materials; graphene sheets can also be combined with other Metal oxides such as SnO 2 (Nano Letters, 2009, 9, (1), 72-75) or TiO 2 (ACS Nano, 2009, 3, (4), 907-914) composite as the negative electrode material, but due to the weak bonding force between the graphene sheet and tin dioxide, the charge and discharge performance of the composite material is not high

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