A new long-cycle mechanism based on p-type@n-type organic composite anode material for dual-ion battery

Organic electrode materials have poor long-cycle performance in dual-ion batteries due to high solubility and low electronic conductivity, which limits its practical application in secondary batteries. In this work, p-type polyaniline (PANI) and n-type polyimide (PI) are used to fabricate composite organic anode materials (PANI@PI). Owing to the differences in reaction mechanisms between PANI and PI materials, the anode of the constructed dual-ion battery could react with both anions and cations simultaneously, resulting in the convergence of the two redox potentials formed by PANI and PI during the process of charging and discharging. This triggers a synergistic effect of electrode reactions in the composite material, improving the long-cycle performance of organic dual-ion batteries. The experimental results show that PANI@PI/EMImTFSI/NG battery has ultra-long-cycle performance. The discharge capacity retention rate is 51.85 % of the maximum capacity (86.64 mAh g −1 ) after 28,000 cycles at 2C. Through the analysis of the structure of composite materials and the kinetics of electrode reactions, it is found that PANI materials gradually activate their electrochemical activity during charging and discharging due to the removal of doping ions. This excitation process synergistically promotes the electrochemical reaction of PI, thus improving the cyclic performance of PANI@PI composite anode materials.