Solvothermal Polymerization and Electrochemical Behavior of Conjugated Polyimide with High Electronic Conductivity and Low Solubility

Abstract

The polymerization of small molecules as electrode materials in lithium-ion batteries not only reduces the solubility but also improves the surface structure and electrical conductivity. The law governing the correlations between the solvothermal temperature of polyimide (PQI) and its surface morphology and structure and electrochemical properties is investigated. The 1st and 200th discharge capacity densities for PQI-180 with fine electrochemical performance at 100 mA g À 1 are 246.6 and 178.5 mAh g À 1 , respectively. The rich pore structure of PQI-180 is conducive to accelerating ion migration and reducing diffusion impedance. In addition, PQI-180 with a uniform threedimensional mesh structure makes sufficient contact with the conductive agent, reducing the electron contact resistance. Unlike previously reported 3-or 4-electron reactions, PQI used as an electrode material shows a 5-electron reaction and a theoretical capacity of 319 mAh g À 1 at voltages ranging from 1.5-3.0 V, and theoretical calculations and experiments explain that this result is due to a new electrochemical reaction mechanism.