Conductive additive for preparing power lithium ion battery cathode material and preparation method thereof

Abstract

The invention provides a conductive additive for preparing power lithium ion battery cathode material and a preparation method of the conductive additive, the conductive additive is a composite of an expanded graphite and a carbon nano tube, one end of the carbon nano tube is located between expanded graphite layers, the other end is exposed outside the expanded graphite. The preparation method comprises the following steps: synthetizing the expanded graphite; interposing one or more of iron, nickel or cobalt between the expanded graphite layers; growing the carbon nano tube between the expanded graphite layers according to gaseous phase catalytic technology; at the last, removing metal impurities. The conductive additive of the invention can significantly improve low-temperature cycle performance and high-rate electrochemical performance of electrodes, can be dispersed and cannot be aggregated easily during electrode material mixing and pulping processes. According to the invention, the preparation method has the advantages of simple operation, easy industrialization application, low energy consumption and lower cost.

Description

technical field [0001] The invention relates to a preparation method of an additive used for lithium-ion battery negative electrode materials, in particular to a preparation method of a conductive additive suitable for the preparation of power lithium-ion battery negative electrode materials. Background technique [0002] Electrode conductive agent is an important material that affects the electrochemical performance of electrode active materials, especially in power lithium-ion batteries, it plays a very critical role, and in some cases it can even directly determine the performance of lithium-ion batteries. Therefore, the research and development of electrode conductive materials and preparation methods for high-end power lithium-ion batteries is extremely valuable for promoting the development of power lithium-ion batteries. [0003] There are both ion diffusion and charge transfer steps in the charging and discharging process of lithium-ion batteries, so the electrode ma...

AI Technical Summary

Problems solved by technology

However, the length-to-diameter ratio of carbon nanotubes is generally high, and carbon nanotubes are prone to self-winding in the process of making electrode sheets, which is not conducive to the uniform dispersion of conductive agents and active particles, and the synthesis of small length-to-diameter ratio The technology of carbon nanotubes is not very mature, and industrialization cannot be realized in a short time