Graphine composite electric conduction agent for iron phosphate lithium battery and preparation method thereof

Abstract

The invention discloses a graphine composite electric conduction agent for an iron phosphate lithium battery, and simultaneously discloses a preparation method of the electric conduction agent. The electric conduction agent provided by the invention consists of graphine, active carbon and a bonding agent in a weight ratio of 1:(0.001-0.1):(0.01-1). The preparation method comprises the following steps: 1) preparing a solution A; 2) preparing a solution B; and 3) preparing the electric conduction agent. According to the invention, the preparation method is simple, the prepared electric conduction agent has the advantages of uniform dispersion, good stability, high electron conduction capability and uniform heat conduction, and the electric conduction agent has higher liquid absorption and liquid protection capabilities when being doped into the iron phosphate lithium battery; and the electric chemical property of the iron phosphate lithium battery which is prepared by adopting the electric conduction agent provided by the invention is improved prominently, compared with the iron phosphate lithium anode material in which the composite electric conduction agent is not doped, when the prepared graphite composite electric conduction agent is doped into the 50AH iron phosphate lithium anode material, the alternating current internal resistance is reduced by 20%, and the circulating service life is improved by 15%.

Description

technical field [0001] The invention relates to the technical field of lithium ion secondary batteries, in particular to a conductive agent for lithium iron phosphate batteries and a preparation method thereof. Background technique [0002] As a new type of high-energy secondary power supply, lithium-ion secondary batteries have the advantages of large specific energy, stable discharge voltage, high voltage, good low-temperature performance, no pollution, superior safety performance, long storage and working life, and high utilization rate. The above-mentioned advantages of lithium-ion secondary batteries have prompted scientists from various countries to compete for research, thereby promoting the rapid development of lithium-ion secondary batteries. There are many kinds of positive electrode materials for lithium-ion secondary batteries, mainly layered lithium cobaltate, lithium nickelate, spinel-like lithium manganate, and olivine-like lithium iron phosphate. The lithium...

AI Technical Summary

Problems solved by technology

At present, the commonly used conductive agents for lithium iron phosphate batteries include granular conductive agents, such as: acetylene black, Super P, granular graphite, metal powder, and composites of two or more different granular conductive substances; fibrous conductive agents, Such as: vapor-phase grown carbon fibers, carbon nanotubes and metal fibers, etc. (patent number: CN200810144527.6), although the above conductive agents can increase the contact probability with the active material lithium iron phosphate, reduce internal resistance, reduce polarization, and then improve electrode Cycling stability, eventually forming an effective conductive network in the electrode and fixing the electrode material, but its improvement is limited