Single organic electrode for multi-system dual-ion symmetric batteries
Wenjun Li, Huilin Ma, Wu Tang, Kexin Fan, Shan Jia, Jian Gao, Ming Wang, Yan Wang, Bei Cao, Cong Fan
Abstract
The large void space of organic electrodes endows themselves with the capability to store different counter ions without size concern. In this work, a small-molecule organic bipolar electrode called diquinoxalino[2,3-a:2’,3’-c]phenazine-2,6,10-tris(phenoxazine) (DQPZ-3PXZ) is designed. Based on its robust solid structure by the π conjugation of diquinoxalino[2,3-a:2’,3’-c]phenazine (DQPZ) and phenoxazine (PXZ), DQPZ-3PXZ can indiscriminately and stably host 5 counter ions with different charge and size (Li+, Na+, K+, PF6− and FSI−). In Li/Na/K-based half cells, DQPZ-3PXZ can deliver the peak discharge capacities of 257/243/253 mAh g−1cathode and peak energy densities of 609/530/572 Wh kg−1cathode, respectively. The Li/Na/K-based dual-ion symmetric batteries can be constructed, which can be activated through the 1st charge process and show the stable discharge capacities of 85/66/72 mAh g−1cathode and energy densities of 59/50/52 Wh kg−1total mass, all running for more than 15000 cycles with nearly 100% capacity retention. Authors report on organic molecule called DQPZ-3PXZ that can stably store 5 counter ions during redox reaction and thus can be simultaneously used to construct three symmetric batteries with stable lifespan.