Sewable and Cuttable Flexible Zinc-Ion Hybrid Supercapacitor Using a Polydopamine/Carbon Cloth-Based Cathode

Abstract

The booming of portable electronics has stimulated great interest in developing flexible Zn-ion hybrid supercapacitors (Zn HSCs) that feature low cost and high operational safety. However, the commercial applications of Zn HSCs are greatly hindered by low energy density due to the low capacity of the cathode and also the invalid weight of the flexible current collector. Here, a free-standing cathode is developed by patterning redox-active polydopamine (PDA) with abundant quinone groups on the porous carbon cloth substrate via a hydrothermal polymerization process. Unlike the traditional carbon cloth-based electrode, the carbon cloth adopted here is activated by the air calcination process, which is beneficial for the loading of PDA and absorption of Zn2+ ions. Benefiting from the hybrid mechanism of Zn2+–quinone group coordination and electrical double layer absorption, the polydopamine-coated porous carbon cloth (PDA@PCC) delivers a high area capacity of 1.25 mA h cm–2 and a high capacity retention of 100% after 10,000 cycles at a current density of 10 mA cm–2. Moreover, when assembled into flexible Zn HSCs, PDA@PCC still displays a high capacity of 0.92 mA h cm–2, and the flexibility and operation safety have also been demonstrated by several extreme condition tests, such as cutting and sewing tests. This work may promote new opportunities for next-generation flexible Zn HSCs.

Recent Progress and Challenges in Multivalent Metal‐Ion Hybrid Capacitors

“…Some other doped carbon‐based materials that can be used as ZHC capacitor‐type electrodes are S‐doped 3D porous carbon (providing a capacity of 203.3 mAh g −1 at 0.2 A g −1 and maintaining a 96.8 % cycle retention after 18000 cycles), [24b] polydopamine layered porous carbon cloth (the maximum area capacity is 1.25 mAh cm −2 , and a 100 % retention rate is achieved after 10,000 cycles), [33] and graphene nanosheet‐manganese sulfide (with specific capacitance of 792 F g −1 , energy density of 25 Wh kg −1 , power density of 7.16 kW kg −1 , and 91 % retention rate after 15,000 cycles) [34] …”

Macromolecular Engineering of Poly(catechol) Cathodes towards High-Performance Aqueous Zinc-Polymer Batteries

“…Both the homopolymer and copolymers featured well-defined oxidation/reduction peaks at 1.3 and 1.27 V/1.14 and 1.20 V (vs. Zn/Zn 2+ ), respectively. As previously demonstrated, these redox processes are associated to the conversion of catecholates to ortho -quinones during the oxidation step and reverse reaction happens during the cathodic sweep reducing ortho -quinones to catecholates with concomitant Zn 2+ coordination (See Figure 1 a for the simplified redox reaction scheme) [ 39 , 40 , 46 , 48 , 51 ]. Taking advantage of poly(catechol)’s high redox potential, Zn||polymer battery with an anticipated voltage output of ~1.2 V can be potentially constructed by combining Zn anode and poly(catechol) cathode in the aqueous electrolyte ( Figure 1 b).…”

“…The following are available online at https://www.mdpi.com/article/10 .3390/polym13111673/s1, Table S1 [38][39][40][41][42][43][44][45][46][47][48][49][50] are cited in the supplementary materials.…”

“…Although numerous RAPs have been successfully applied as OEMs in different rechargeable battery technologies, only a limited number of redox polymers were positively evaluated in AZMB (see Table S1 ) [ 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 , 47 , 48 , 49 , 50 ]. Here onwards we use an acronym AZPB for the AZMB comprising a polymer cathode and Zn metal anode.…”

Zinc‐Ion Hybrid Supercapacitors: Progress and Future Perspective

“…Aside from carbon materials and inorganic metal oxides/carbides, or phosphorene, redox‐active polymer materials can also be employed as electrodes for ZIHSCs. Flexible carbon cloth was activated through air calcination, resulting in porous carbon cloth (PCC) with oxygen‐containing groups, better hydrophilicity and higher SSA [34] . PCC was used as the substrate for subsequent hydrothermal polymerization of poly‐dopamine (PDA).…”