Preparation method of carbon-coated sodium titanium phosphate composite material and preparation method of negative pole piece

Abstract

The invention discloses a preparation method of a carbon-coated sodium titanium phosphate composite material and a preparation method of a negative pole piece. The preparation method of the carbon-coated sodium titanium phosphate composite material comprises the following steps: (1) adding a carbon source, a sodium source, a phosphorus source and a titanium source into a dispersing agent, and stirring to obtain slurry; (2) stirring and refluxing the slurry, removing part of the dispersing agent under reduced pressure, and drying to obtain a powdery precursor; and (3) pressing the precursor into a rough blank, calcining in an inert atmosphere, and cooling to obtain the carbon-coated sodium titanium phosphate composite material. The preparation method of a carbon-coated sodium titanium phosphate negative pole piece comprises the following steps: S1, mixing water-based conductive slurry, water-based glue and a solvent, adding a conductive agent and the carbon-coated sodium titanium phosphate composite material, and uniformly stirring to obtain water-based coating slurry; and S2, coating a hydrophobic carbon-coated aluminum foil with the water-based coating slurry, drying, compacting and slitting to obtain the carbon-coated sodium titanium phosphate negative pole piece. According to the methods, no harmful or corrosive gas is discharged, the methods are green and environment-friendly production processes, and the used raw materials are common and cheap.

Description

technical field [0001] The invention relates to the field of nanomaterial technology and electrochemistry, and in particular to a carbon-coated sodium titanium phosphate composite material and a method for preparing a carbon-coated sodium titanium phosphate negative pole piece. Background technique [0002] Secondary batteries play an important role in the transformation of old and new energy forms and the utilization and development of new energy. At present, although lead-acid batteries and lithium-ion batteries have been widely used in mobile power sources, energy storage and other fields, due to their respective defects, new battery systems are beginning to develop rapidly, and emerging water-based batteries have attracted much attention. [0003] Sodium titanium phosphate (NaTi 2 (PO 4 ) 3 ), is a polyanionic material whose three-dimensional polyanionic framework has the advantages of high ion conductivity and high structural stability. As a negative electrode mater...

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Problems solved by technology

Currently existing laboratory preparation techniques such as hydrothermal method or sol-gel method are not suitable for large-scale production. Even if some technologies can achieve large-scale production, there are the following problems: 1. Almost all technologies use ammonium dihydrogen phosphate or phosphoric acid Ammonium and other decomposable phosphates are phosphorus sources, which will produce a large amount of corrosive and harmful tail gas—ammonia gas. The production of ammonia gas will not only increase the risk of environmental pollution, but also greatly increase the complexity of equipment and production after treatment. cost; 2. At present, many technologies use the process of wet grinding, dispersing and drying raw materials in the production process. The existing spray drying technology needs to consume a lot of energy; 3. Although phosphoric acid is cheap and the by-products produced by decomposition are only Water is in line with the concept of green production, but because phosphoric acid itself is a viscous liquid, it cannot be prepared into a powder precursor with other raw materials. At present, it is impossible to use phosphoric acid as a phosphorus source to achieve large-scale preparation of sodium titanium phosphate

Electrode pole pieces prepared with ordinary water-based glue cannot be used in batteries with aqueous solution as the electrolyte, because when the electrode pole piece encounters the aqueous electrolyte again, it will expand, causing the active material to be released from the current collector. Falling off, affecting battery performance and cycle life

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