A kind of nano-graphite conductive agent for lithium iron phosphate battery and preparation method thereof

Abstract

The invention discloses a nano-graphite conductive agent for a lithium iron phosphate battery and a preparation method of the conductive agent. The nano-graphite conductive agent comprises the following components in percentage by mass: 22-40 percent of nano-graphite particles, 0.2-0.8 percent of a dispergator, 0.2-0.6 percent of a dispersing agent, 0.1-0.8 percent of a protective agent, 0.1-0.5 percent of a wetting agent and the balance of deionized water. The preparation method comprises the following steps: preparing the nano-graphite particles, preparing the nano-graphite conductive agent and the like. According to the nano-graphite conductive agent for the lithium iron phosphate battery disclosed by the invention, the conductivity and gram volume of lithium iron phosphate can be improved; the charging efficiency is accelerated, the direct current internal resistance is reduced, the electrochemical performance of a lithium ion battery is improved, and the manufacturing cost is reduced. The preparation method disclosed by the invention is low in energy consumption, high in efficiency and extremely little in scrap iron, and harmless discharge can be realized.

Description

technical field [0001] The invention relates to the technical field of lithium ion batteries, in particular to a nanographite conductive agent for lithium iron phosphate batteries and a preparation method thereof. Background technique [0002] Since A.K.Padni first reported that lithium iron phosphate can be used as a cathode material for lithium-ion batteries in 1997, it has attracted widespread attention and a lot of research. Olivine lithium iron phosphate (LiFePO 4 ) has a theoretical specific capacity of 170mAh / g and a lithium charge and discharge voltage platform of about 3.5V, and the charge and discharge curve is very flat, which is different from that of traditional LiCoO 2 , LiNiO 2 and LiMn 2 o 4 Compared with other cathode materials, LiFePO 4 As a positive electrode material, it has outstanding advantages such as good thermal stability, excellent cycle performance, and high safety. From the perspective of resources, the preparation of LiFePO 4 The raw mater...

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Problems solved by technology

The carbon source used in the synthesis process is organic carbon such as glucose, which requires a high-temperature pyrolysis process to generate pyrolytic carbon to reduce Fe 3+ and to achieve carbon coating, the LiFePO 4 During the synthesis process, if the calcination temperature is too low, it will cause LiFePO 4 / C crystallization is not complete

If the calcination temperature is too high, it will lead to LiFePO 4 / C grains are too large, which increases the diffusion path of lithium ions, resulting in a decrease in the electrochemical performance of the material, and the conductivity of pyrolytic carbon is far inferior to that of natural graphite

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