A Bipolar and Self-Polymerized Phthalocyanine Complex for Fast and Tunable Energy Storage in Dual-Ion Batteries

Bipolar redox organics have attracted interest as electrode materials for energy storage owing to their flexibility, sustainability and environmental friendliness. However, an understanding of their application in all-organic batteries, let alone dual-ion batteries (DIBs), is in its infancy. Herein, we propose a strategy to screen a variety of phthalocyanine-based bipolar organics. The self-polymerizable bipolar Cu tetraaminephthalocyanine (CuTAPc) shows multifunctional applications in various energy storage systems, including lithium-based DIBs using CuTAPc as the cathode material, graphite-based DIBs using CuTAPc as the anode material and symmetric DIBs using CuTAPc as both the cathode and anode materials. Notably, in lithium-based DIBs, the use of CuTAPc as the cathode material results in a high discharge capacity of 236 mAh g^-1 at 50 mA g^-1 and a high reversible capacity of 74.3 mAh g^-1 after 4000 cycles at 4 A g^-1 . Most importantly, a high energy density of 239 Wh kg^-1 and power density of 11.5 kW kg^-1 can be obtained in all-organic symmetric DIBs.