Organic cathode materials with redox-active sites and flexible structure are promising for developing aqueous zinc ion batteries with high capacity and large output power. However, the energy storage of most organic hosts relies on the coordination/incoordination reaction between Zn 2+ /H + and a single functional group, which result in inferior capacity, low discharge platform, and structural instability. Here, the lead is taken in in situ electrodepositing stable poly(1,5-naphthalenediamine, 1,5-NAPD) as interlayer and excellent conductive poly(para-aminophenol, pAP) skin onto nanoporous carbon in sequence for the structural optimization of organic/organic cathodes, designated as C@multi-layer polymer. In situ analyses, electrochemical measurements, and theoretical calculation prove that both CO and CN active groups can act as a strong electron donor as well as Zn 2+ host during the discharging process. Benefiting from the synergistic effect of the double organic layers, C@multi-layer polymer delivers high capacity, long lifespan, and excellent capacity reservation even at large discharge current and commercial mass loading (>10 mg cm −2 ). Introducing multiredox centers into one organic composites will provide new insights into designing advanced Zn–organic batteries.
Bottom-up molecular engineering by rational design has emerged as a promising strategy for exploring advanced organic cathodes. However, directly programming organic moieties into high-performance electro-active materials remains a great challenge. Herein, we design and synthesize a hydrogen-bonded supramolecule (hexaazatrinaphthalene hexacarbonitrile, HATN-6CN) anchored with abundant cyano groups, which ensures structural stability, extended π-conjugated system, and multiple redox active centers. As a result, the HATN-6CN cathode delivers a high specific capacity (297.6 mAh g –1 at 0.5 A g –1 , 225.2 mAh g –1 at 5 A g –1 ) and outstanding long-term cycling performance (191.9 mAh g –1 over 1000 cycles at 5 A g –1 with a capacity retention of 85.2 %). Moreover, the charge storage mechanisms, structural evolution, and reversibility during the redox process of HATN-6CN were systematically investigated. This work offers a feasible and promising avenue for bottom-up molecular engineering of organic electrodes by rational design.
Near-infrared electrochromic materials have garnered great attention due to their potential applications in optical data storage and military camouflage. Herein, a networked metal-organic coordination polymer bearing multi-redox centra ( Fe-MCP ) was successfully prepared by coordination interaction of Fe ions with D-A-D-structure ligands through the liquid-liquid interface self-assembly strategy. The resultant uniform film exhibits improved NIR electrochromic attributed to the construction of mixed-valence system. Furthermore, a sandwich-structured electrochromic device was fabricated by combining Fe-MCP electrochromic layer, a gel composed of LiClO 4 , PMMA , and PC as the electrolyte layer, and anodically coloring PB as an ion storage layer. The resultant device illustrated an optical contrast of 31.4 % at 800 nm and 34.2 % at 1000 nm, a response speed of 4.0 s/8.3 s at 800 nm and 7.6 s/2.7 s at 1000 nm, and good cycling durability. The design principles proposed in this study provide a new insight for the preparation of high-performance NIR electrochromic materials .
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