Dicyanotriphenylamine-Based Polyimides as High-Performance Electrodes for Next Generation Organic Lithium-Ion...

Aromatic polyimide (PI) derivatives have recently been investigated as redox-active electrode materials for Li-ion batteries because of their high thermal stability and thermo-oxidative stability complemented by excellent solvent resistance, good electrical and mechanical properties, and chemical resistance. In this work, we report two PI derivatives from a newly synthesized 4,4'-diamino-3″,4″-dicyanotriphenylamine (DiCN-TPA) monomer and two dianhydrides, pyromellitic dianhydride (PMDA) and 1,4,5,8-naphthalenetetracarboxylic dianhydride (NTCDA); designated as TPA-PMPI and TPA-NTCPI, respectively, as electrode materials for Li-ion batteries. Characterizations of the PIs reveal excellent thermal stability and bipolar property. The incorporation of DiCN-TPA into the polymer structure resulted to a disordered chain arrangement, thus giving high glass transition temperatures (T_g). Electrochemical performance tests reveal that TPA-NTCPI cathode delivered a reversible specific capacity of 150 mAh g^-1 at 0.1 A g^-1 and exhibited a stability up to 1000 cycles. On the other hand, TPA-PMPI anode delivered a high specific capacity of up to 1600 mAh g^-1 at 0.1 A g^-1 after 100 cycles. The electrochemical performance of TPA-NTCPI cathode and TPA-PMPI anode are both among the best compared with other reported aromatic PI-based electrodes. The long cycle lifetime and excellent battery performance further suggest that TPA-NTCPI and TPA-PMPI are promising organic electrode materials for next generation Li-ion batteries.