Graphene‐Based Planar Microsupercapacitors: Recent Advances and Future Challenges

Zhang

et al. 2020

Adv Funct Materials

107

The advancement of miniaturized electronic devices requires the development of high-performance microsupercapacitors. The low areal energy density of microsupercapacitors with the interdigitated architecture is the major challenge hindering the application. Here, a simple method for the scalable fabrication of all-solid-state, flexible microsupercapacitors is demonstrated by direct graphene-carbon nanotube composite ink writing technology. The microsupercapacitors demonstrate good electrochemical performance with a high areal energy density of 1.36 µWh cm -2 and power density of 0.25 mW cm -2 , good cycling stability, and excellent mechanical flexibility. The method developed here sheds light on the simple method of preparing high-performance, all-solid-state, flexible microsupercapacitors in a straightforward and scalable process.

Section: Introductionmentioning

confidence: 99%

Direct Graphene‐Carbon Nanotube Composite Ink Writing All‐Solid‐State Flexible Microsupercapacitors with High Areal Energy Density

Zhang

et al. 2020

Adv Funct Materials

107

ACS Appl. Mater. Interfaces

“…[1][2][3][4] and supercapacitors (both conventional and small-scale devices). 2,3,5 As regards the former type of EES device, it is worth noting that current metal-ion batteries have reached their limits in terms of theoretical energy density, cycle life and charge/discharge rate, and so the development of a sustainable energy grid requires the implementation of new generations of batteries with enhanced features. In this context, metal-air (M-O2) batteries have arisen as an attractive alternative to conventional batteries due to their high theoretical energy density.…”

Section: Introductionmentioning

confidence: 99%

Aqueous Cathodic Exfoliation Strategy toward Solution-Processable and Phase-Preserved MoS₂ Nanosheets for Energy Storage and Catalytic Applications

García‐Dalí

Paredes

Munuera

et al. 2019

Integrated approaches that expedite the production and processing of graphene into useful structures and devices, particularly through simple and environmentally friendly strategies, are highly desirable in the efforts to implement this two-dimensional material in state-of-the-art electrochemical energy storage technologies. Here, we introduce natural nucleotides (e.g., adenosine monophosphate) as bifunctional agents for the electrochemical exfoliation and dispersion of graphene nanosheets in water. Acting both as exfoliating electrolytes and colloidal stabilizers, these biomolecules facilitated access to aqueous graphene bio-inks that could be readily processed into aerogels and inkjetprinted interdigitated patterns. Na-O2 batteries assembled with the graphene-derived aerogels as the cathode and a glyme-based electrolyte exhibited a full-discharge capacity of ~3.8 mAh cm-2 at a current density of 0.2 mA cm-2. Moreover, shallow cycling experiments (0.5 mAh cm-2) boasted a capacity retention of 94% after 50 cycles, which outperformed the cycle life of prior graphene-based cathodes for this type of battery. The positive effect of the nucleotide-adsorbed nanosheets on the battery performance is discussed and related to the presence of the phosphate group in these biomolecules. Micro-supercapacitors made from the interdigitated graphene patterns as the electrodes also displayed a competitive performance, affording areal and volumetric energy densities of 0.03 Wh cm-2 and 1.2 mWh cm-3 at power densities of 0.003 mW cm-2 and 0.1 W cm-3 , respectively. Taken together, by offering a green and straightforward route to different types of functional graphene-based materials, the present results are expected to ease the development of novel energy storage technologies that exploit the attractions of graphene.

“…Graphene can be used for the direct laying down of conductive or semi-conductive patterns on organic, flexible, transparent, wearable electronic devices, as well as being used in biomedical and nanomedicine applications, quantum devices, magnetic devices, super capacitors and small-scale, efficient energy storage devices, oil and petroleum, water treatment systems, biosensors, and even, in the possible construction of room temperature superconductive materials. [256][257][258][259] Recently, it has been shown that properties such as superconductivity or magnetism can be detected in a graphene bilayer in which the layers have been twisted with respect to each other at a so-called "magic" angle ( � 1.1 degrees). [260,261] Recently, flexible graphene based field effect transistors have been fabricated which are capable of monitoring slow brain waves (< 0.1 Hz) with high spatial resolution; this achievement could open new windows for the non-invasive wearable study of brain functions, including sleep, wakefulness, coma and anesthesia, allowing construction of more effective brain-machine interfaces and contributing to neuroscience studies.…”

Section: Applications Conclusion and Future Outlookmentioning

confidence: 99%

Recent Developments in Graphene and Graphene Oxide: Properties, Synthesis, and Modifications: A Review

et al. 2020

Graphene was first discovered as a sheet structure mechanically exfoliated from a block of graphite, but in recent years researchers have extended their investigations into this two‐dimensional carbon nanostructure. Various applications of graphene‐based materials have included electronics, photonics, optoelectronics, sensors, and drug / gene delivery systems. These single atom carbon layers have the potential to be formed in different morphologies e. g., quantum dots, nanosheets, and nanoparticles, which can be tailored to achieve new breakthrough innovations. Nowadays, the utilization of graphene‐based nanomaterials in medicine is a hot research topic. This review discusses the structure, properties, methods of synthesis, and surface modifications of graphene and graphene oxide divided into covalent and non‐covalent approaches.