Single organic electrode for multi-system dual-ion symmetric batteries.

Li, Wenjun; Ma, Huilin; Tang, Wu; Fan, Kexin; Jia, Shan; Gao, Jian; Wang, Ming; Wang, Yan et al. · Nat Commun · 2024

basic_science · Level V

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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<sup>+</sup>, Na<sup>+</sup>, K<sup>+</sup>, PF<sub>6</sub><sup>-</sup> and FSI<sup>-</sup>). In Li/Na/K-based half cells, DQPZ-3PXZ can deliver the peak discharge capacities of 257/243/253 mAh g<sup>-1</sup><sub>cathode</sub> and peak energy densities of 609/530/572 Wh kg<sup>-1</sup><sub>cathode</sub>, 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<sup>-1</sup><sub>cathode</sub> and energy densities of 59/50/52 Wh kg<sup>-1</sup><sub>total mass</sub>, all running for more than 15000 cycles with nearly 100% capacity retention.