Melamine-Based Polyimide Covalent Organic Framework: A High-Performance Cathode Material for High-Temperature Lithium-Ion Batteries

Abstract

To address the issues of poor thermal stability, rapid capacity decay, and low safety of traditional inorganic lithium-ion battery cathode materials under high-temperature conditions, this paper develops a polyimide covalent organic framework (PI-COF) cathode material based on melamine and 1,4,5,8-naphthalenetetracarboxylic dianhydride. A polyamic acid precursor was prepared via a hydrothermal method, followed by high-temperature imidization at 355°C to obtain PI-COF with a periodic ordered pore structure. The electrode was fabricated by compositing PI-COF with reduced graphene oxide (rGO). Electrochemical tests show that the electrode can stably cycle for more than 1500 cycles at a current density of 1 A/g at room temperature, with a peak specific capacity of 821.5 mAh/g. Under the high-temperature condition of 100°C, it delivers an initial specific capacity of 324.7 mAh/g and can stably cycle for more than 120 times. The material features a simple preparation process, low cost, and environmental friendliness, showing broad application prospects in lithium-ion batteries for extreme high-temperature operating conditions.