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ACS Appl Mater Interfaces ; 14(1): 1478-1488, 2022 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-34928125


Transparent flexible supercapacitors (TFSCs) are a tantalizing power supplier for future transparent flexible electronics. However, their energy density is far behind a practical level while maintaining high transparency. We report here a transparent flexible potassium-ion microcapacitor, and its high energy density (15.5 µWh cm-2) roots in the battery-supercapacitor hybrid storage mechanism and much enlarged working voltage (3 V), outperforming the state-of-the-art TFSC, which is generally based on an aqueous electrolyte and an asymmetric pseudocapacitive mechanism. From an electrode material perspective, a multidimensional topotactic host composite anode is designed in which the component not only performs energy storage by synchronous and reversible uptake of potassium ions and electrons into its host structure, but also mutually compensates individual weakness in functional and structural aspects, efficiently constructing a three-dimensional potassium-ion diffusion and electron transport system. This conceptual exhibition provides design principles at material and device levels for high-performance TFSCs.

ACS Appl Mater Interfaces ; 13(45): 54096-54105, 2021 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-34749501


Aqueous zinc-ion batteries (ZIBs) are regarded as a promising candidate for ultrafast charge storage owing to the high ionic conductivity of aqueous electrolytes and high theoretical capacity of zinc metal anodes. However, the strong electrostatic interaction between high-charge-density zinc ions and host materials generally leads to sluggish ion-transport kinetics and structural collapse of rigid cathode materials during the charge/discharge process, so searching for suitable cathode materials for ultrafast and long-term stable ZIBs remains a great challenge. Herein, flexible electron-rich ion channels enabling fast-charging and stable aqueous ZIBs have been demonstrated. Because of the nitrogen-rich conjugated structure of organic phenazine (PNZ) molecules, electron-rich ion channels are formed with the C═N redox centers situated on the channel surface, where zinc ions can transport rapidly and react with active moieties directly. Meanwhile, the π-conjugated systems and inherent flexibility of PNZ molecules can accommodate rapid strain changes and maintain their structural stability during zinc-ion intercalation/deintercalation. Consequently, they exhibit a high capacity of 94.2 mAh g-1 at an ultrahigh rate of 700C (208.6 A g-1) and an ultralong life over 100,000 cycles at 100C, which are superior to those of previously reported aqueous ZIBs. Our work presents a new way for developing ultrafast and ultrastable aqueous ZIBs.

Adv Mater ; 32(4): e1904876, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31697001


The shuttling behavior and sluggish conversion kinetics of the intermediate lithium polysulfides (LiPSs) represent the main obstructions to the practical application of lithium-sulfur (Li-S) batteries. Herein, an anion-deficient design of antimony selenide (Sb2 Se3- x ) is developed to establish a multifunctional LiPS barrier toward the inhibition of polysulfide shuttling and enhancement of battery performance. The defect chemistry in the as-developed Sb2 Se3- x promotes the intrinsic conductivity, strengthens the chemical affinity to LiPSs, and catalyzes the sulfur electrochemical conversion, which are verified by a series of computational and experimental results. Attributed to these unique superiorities, the obtained LiPS barrier efficiently promotes and stabilizes the sulfur electrochemistry, thus enabling excellent Li-S battery performance, e.g., outstanding cyclability over 500 cycles at 1.0 C with a minimum capacity fading rate of 0.027% per cycle, a superb rate capability up to 8.0 C, and a high areal capacity of 7.46 mAh cm-2 under raised sulfur loading. This work offers a defect engineering strategy toward fast and durable sulfur electrochemistry, holding great promise in developing practically viable Li-S batteries as well as enlightening the material design of related energy storage and conversion systems.

ACS Appl Mater Interfaces ; 11(20): 18645-18653, 2019 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-31042350


Highly sensitive mechanical sensing is vital for the emerging field of skin mimicry and wearable healthcare systems. To date, it remains a big challenge to fabricate mechanosensors with both high sensitivity and a wide sensing range. In nature, slit sensilla are crack-shaped sensory organs of arachnids, which are highly sensitive to tiny external mechanical stimuli. Here, inspired by the geometry of slit sensilla, a concept is developed that pretextures reduced graphene oxide (RGO) nanocoating into multiscale topographies with agminated crumples and interlaced cracks (crumpled & cracked RGO) through an efficient and scalable mechanically driven process. Both the sensitivity and the workable range can be facilely tuned by adjusting the crack density. The resulting mechanosensor exhibits a comprehensive superior performance including high sensitivity (a gauge factor of 205 to 3256), a wide and tunable sensing range (from 0-40 to 0-180%), long-term stability (over 5000 cycles), and multiple sensing functions. Based on its excellent performances, the mechanosensor can be used as a wearable electronic to in situ monitor subtle physiological signals and vigorous body actions. The rationally designed crumpled & cracked RGO provides a promising platform for artificial electronic skin and portable healthcare systems.

Grafite , Dispositivos Eletrônicos Vestíveis , Propriedades de Superfície