关键词: 1,5-二氨基蒽醌, ZIF-8C, 金属有机骨架材料, 导电粘合剂, 锂离子电池

Organic conjugated small molecular material 1,5-diaminoanthraquinone (AAQ), as an organic cathode material for lithium-ion battery, has become the research focus of new energy battery materials because of its simple preparation, high theoretical specific capacity and stable cycle performance. However, due to its poor conductivity and dissolution in electrolyte, its electrochemical properties are affected, which limits its further application. In this work, AAQ was dispersed in metal organic framework porous materials (MOFs) - Nitrogen-doped porous carbon (ZIF-8C) by ultrasonic method, and then porous carbon framework composites AAQ@ZIF-8C were prepared by heat-treatment method. Copolymer PAA-PAN was prepared by solution polymerization method with polyacrylic acid (PAA) and aniline (AN) monomer. Finally, AAQ@ZIF-8C/ PAA-PAN composite electrode material were prepared with above materials by ball milling method. The structure, morphology and electrochemical properties of the composite electrode materials were characterized by infrared spectroscopy, scanning electron microscopy, electrochemical cyclic voltammetry and AC impedance method. When PAA-PAN combined with AAQ@ZIF-8C, the conductive interpenetrating network structure is formed in AAQ@ZIF-8C/PAA-PAN composite, which not only improves the conductivity of the electrode active material AAQ, but also inhibits the solubility of AAQ in the electrolyte. In addition, the porous ZIF-8C skeleton material is conducive to the rapid diffusion and migration of electrolyte ions and improves the reversible capacity of the battery. High solubility in aprotic organic electrolytes and poor electrical conductivity are the main restrictions of organic electrodes in practical application. Conductive binder contributes to the high-performance electrodes as it enables both mechanical and electronic integrity of the electrode, which have been scarcely explored for organic electrodes. As we know, state-of-the-art lithium-ion battery (LIB) electrodes choose polyvinylidene fluoride (PVDF) as the binder because of its good chemical and electrochemical stability. Herein, a conductive interpenetrating polymeric network is synthesized through in situ polymerization of polyaniline with poly(acrylic acid) (denoted PAA-PAN), which served as a novel conductive binder for organic AAQ materials. The PAA was chosen as the matrix component for the reason that PAA contains sufficient carboxyl groups (-COOH), which can condense with the amino groups (-NH₂) of polyaniline. Therefore, a conductive interpenetrating network can be formed in the process of in-situ polymerization. The conductive PAN component enhances the electrical conductivity of the electrode. Meanwhile, the PAA component serves as the binding matrix to condense with the amino groups (-NH₂) of AAQ, which therefore effectively inhibits their dissolution and maintains electrode integrity during cycling. The electrochemical results showed that the lithium ion battery assembled with the composite electrode material has a reversible capacity of 203 mAh•g^-1 at a Coulomb rate of 0.1 C, which is close to its theoretical specific capacity of 225 mAh•g^-1. After 200 cycles, the reversible capacity is still 195 mAh•g^-1 and the coulomb efficiency is 95%.

Key words: 1,5-diaminoanthraquinone, ZIF-8C, metal organic framework materials, conductive binder, lithium ion battery