A self-healing hydrogel electrolyte for flexible solid-state supercapacitors
TL;DR: In this article, a self-healing hydrogel electrolyte with excellent tensile properties and good conductivity under large strain/stress was demonstrated. But the performance of the electrolyte was not evaluated.
About: This article is published in Chemical Engineering Journal.The article was published on 2020-12-01. It has received 80 citations till now. The article focuses on the topics: Electrolyte & Supercapacitor.
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TL;DR: In this article, transition metal compounds (TMCs) have been used as electrode materials of supercapacitors to raise the insufficient energy density by the reverse reaction among their multiple oxidation states.
165 citations
TL;DR: The transition from conventional LIB system towards higher smartness and the incurred advantages/challenges are overviewed, and the potential change of system-level smart battery integration is further discussed as an open outlook.
156 citations
TL;DR: In this paper, hollow cobalt molybdenum selenide (CoMo-Se) nanosheet arrays are fabricated via a self-sacrificing template method and selenization process, where cobalt-organic framework serves as the template.
70 citations
TL;DR: In this article, a 3D printed carbon aerogel (CA) microlattices are designed with tunable thickness to realize high areal capacitance, achieving a desirable areal/volumetric capacitance (870.3 mF cm−2/1).
Abstract: Desirable areal and volumetric capacitances of electrodes with high mass loading are of great significance for compact energy storage in practical applications. The key challenge remains in the structural design of electrodes with interconnected micro-/macro-networks for unimpeded electron and ion transport. Herein, three-dimensional (3D) printed carbon aerogel (CA) microlattices are designed with tunable thickness to realize high areal capacitance. By using polyamic acid (PAA) as a crosslinker, graphene oxide/polyamic acid (GP) ink exhibits ideal printability and formability to ensure the continuous printing of self-supported and programmable 3D structures. After subsequent freeze-drying and thermal treatment, the as-obtained CA exhibits not only a well-maintained macrostructure of the extruded shape but also a porous microstructure from the interconnected GP gel. As a result, the 3D printed CA microlattice presents a quasi-proportional increase in areal capacitance with thickness, achieving a desirable areal/volumetric capacitance (870.3 mF cm−2/1.7 F cm−3) under high mass loading (15.3 mg cm−2) and large thickness (4.9 mm). This work offers a promising strategy to construct a customizable structure of a supercapacitor and provides new insights to dramatically improve the energy storage properties of microdevices with limited area.
66 citations
TL;DR: In this article, a quasi-solid-state polyelectrolyte hydrogel with a superhigh concentration of CH3COOK through in situ polymerization was developed to accommodate ultra-high ion concentration.
Abstract: Recently, "water-in-salt" electrolytes have provided a huge boost to the realization of high energy density for water-based supercapacitors by broadening the electrochemical stability window. However, the high cost and low conductivity of high concentration LiTFSI greatly restrict the possibility of practical application. Herein, we adopt a new strategy to develop a low-cost and quasi-solid-state polyelectrolyte hydrogel accommodating a superhigh concentration of CH3COOK through in situ polymerization, avoiding the problem that many conventional polymers cannot accommodate ultra-high ion concentration. The polyelectrolyte hydrogel with 24 M CH3COOK exhibits a conductivity of up to 35.8 mS cm-1 and a stretchability of 950%. With advanced N-doped graphene hydrogel electrodes, the assembled supercapacitor yields a voltage window of 2.1 V with an energy density of 33.0 W h kg-1 and superior cyclability with 88.2% capacitance retention at 4 A g-1 after 6000 cycles comparable to those supercapacitors using high-cost LiTFSI salts. Besides, the supercapacitor with excellent temperature stability in the range of -20 to 70 °C can light an LED for more than one minute. The assembled flexible device with the PAAK/CMC-24 M gel film sandwiched in between demonstrates excellent bendability from 0° to 180° and shows great potential for flexible/wearable electronic devices. Our feasible approach provides a new route for assembling quasi-solid-state flexible high-energy storage devices with "water-in-salt" electrolytes.
53 citations
References
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TL;DR: An asymmetric supercapacitor with high energy density has been developed successfully using graphene/MnO2 composite as positive electrode and activated carbon nanofibers (ACN) as negative electrode in a neutral aqueous Na2SO4 electrolyte as mentioned in this paper.
Abstract: Asymmetric supercapacitor with high energy density has been developed successfully using graphene/MnO2 composite as positive electrode and activated carbon nanofibers (ACN) as negative electrode in a neutral aqueous Na2SO4 electrolyte. Due to the high capacitances and excellent rate performances of graphene/MnO2 and ACN, as well as the synergistic effects of the two electrodes, such asymmetric cell exhibits superior electrochemical performances. An optimized asymmetric supercapacitor can be cycled reversibly in the voltage range of 0–1.8 V, and exhibits maximum energy density of 51.1 Wh kg−1, which is much higher than that of MnO2//DWNT cell (29.1 Wh kg−1). Additionally, graphene/MnO2//ACN asymmetric supercapacitor exhibits excellent cycling durability, with 97% specific capacitance retained even after 1000 cycles. These encouraging results show great potential in developing energy storage devices with high energy and power densities for practical applications.
1,768 citations
TL;DR: The state-of-the-art advancements in FSSCs are reviewed to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs.
Abstract: Flexible solid-state supercapacitors (FSSCs) are frontrunners in energy storage device technology and have attracted extensive attention owing to recent significant breakthroughs in modern wearable electronics In this study, we review the state-of-the-art advancements in FSSCs to provide new insights on mechanisms, emerging electrode materials, flexible gel electrolytes and novel cell designs The review begins with a brief introduction on the fundamental understanding of charge storage mechanisms based on the structural properties of electrode materials The next sections briefly summarise the latest progress in flexible electrodes (ie, freestanding and substrate-supported, including textile, paper, metal foil/wire and polymer-based substrates) and flexible gel electrolytes (ie, aqueous, organic, ionic liquids and redox-active gels) Subsequently, a comprehensive summary of FSSC cell designs introduces some emerging electrode materials, including MXenes, metal nitrides, metal–organic frameworks (MOFs), polyoxometalates (POMs) and black phosphorus Some potential practical applications, such as the development of piezoelectric, photo-, shape-memory, self-healing, electrochromic and integrated sensor-supercapacitors are also discussed The final section highlights current challenges and future perspectives on research in this thriving field
1,210 citations
TL;DR: In this paper, the effects of activation temperature and impregnation ratio on the pore structure and surface chemistry of activated carbons derived from jackfruit peel with chemical activation method using phosphoric acid as activating agent were studied.
704 citations
TL;DR: In this paper, a three-dimensional flower-like and hierarchical porous carbon material (FHPC) has been fabricated through a simple and efficient carbonization method followed by chemical activation with flowerlike ZnO as template and pitch as carbon precursor.
571 citations
TL;DR: In this paper, a review of the preparation methods and various properties of graphene oxide is presented, followed by a discussion on the working parameters of the two different electrochemical routes and the associated electrochemical techniques used to produce graphene.
453 citations