Bendable Aqueous Zinc-Ion Hybrid Energy Storage Device Using Poly(4,4’-thiodianiline)-Modified Nanoporous Carbon Cathode

Graphical Zinc-ion hybrid supercapacitor : An organic cathode is made by electrodepositing poly(4,4’-thiodianiline) onto a nanoporous activated carbon coating and is combined with Zn anode to make a hybrid aqueous energy storage device that combines merits of both ionic battery and supercapacitor. The Zn 2+ based battery systems have attracted considerable interest because of the bivalent ions as charge carriers and merits of Zn anode. Herein, we demonstrate a Zn-ion hybrid energy storage device consisting of a Zn anode and a cathode made of poly(4,4’-thiodianiline)-coated activated carbon (AC). This redox-active polymer that is electrodeposited onto nanoporous AC granules has the function of boosting the energy storage capacity, reaching 181.3 mAh g −1 . The Zn-ion cell exhibits good cycling stability, as the capacity retention is 83 % after 5000 cycles. Aqueous electrolytes using different zinc salts are prepared and their influences on the formation of byproducts and cycling stability of the cell are investigated. The charge/discharge mechanism of the polymer cathode is discussed in detail. Moreover, for practical applications, bending tests are performed on the flexible Zn-ion cell, and it remains stable capacity when being repeatedly bent.