A novel pitch-based spherical porous doping method for modifying a hard carbon anode material

Abstract

The invention discloses a novel pitch-based spherical porous doping method for modifying hard carbon negative electrode material, and includes such steps as pulverizing high-temperature coal-based pitch, adding crosslinking agent under N2 protection, stirring and heating molten pitch, crosslinking reaction between pitch and crosslinking agent to prepare crosslinked pitch, adding oxidant, adding O2, stirring and isothermal reaction to obtain crosslinked oxidized pitch; (2) spray granulation; (3) carbonization of pitch microspheres; (4) coating and graphitization of pitch-based hard carbon. By using low temperature spray granulation method to prepare regular spherical porous asphalt-based microspheres, spherical hard carbon prepared by carbonization and coating has compaction density of morethan 1.1 g / cm3, the compaction density is high, reversible specific capacity is greater than 400 mAh / g, first coulombic efficiency greater than 80%, the capacity retention ratio after 500 cycles is greater than 85%, the 30C / 1C capacity retention ratio is greater than 98%, electrochemical performance is better, the effects of safety and environmental protection, and economy and efficiency are achieved, the process is simple, and industrial large-scale production is easy to realize.

Description

technical field [0001] The invention relates to the technology in the field of negative electrode materials, in particular to a novel method for pitch-based spherical porous doping modified hard carbon negative electrode materials. Background technique [0002] Carbon anode materials are currently the most cost-effective and ideal anode materials for lithium-ion batteries, but the theoretical maximum lithium intercalation capacity of graphite is only 372mAh / g. Due to the high degree of graphitization, the traditional graphite anode material has a highly oriented layered structure and poor compatibility with the electrolyte. It is prone to co-intercalation of solvent ions during the charging and discharging process, resulting in delamination between graphite layers, particle collapse, and electrode powder. , leading to poor rate performance, low cycle performance, and potential safety hazards. Hard carbon refers to carbon that is difficult to graphitize, consisting of small ...

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Problems solved by technology

[0011] In view of this, the present invention aims at the deficiencies in the prior art, and its main purpose is to provide a new method of pitch-based spherical porous doped modified hard carbon negative electrode material, which can effectively solve the capacity of the existing composite hard carbon and the low Coulombic efficiency

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