3-Dimensional Graphene Carbon Nanotube Carpet-Based Microsupercapacitors with High Electrochemical Performance

Abstract

In this research, 3-dimensional (3D) graphene/carbon nanotube carpets (G/CNTCs)-based microsupercapacitors (G/CNTCs-MCs) were fabricated in situ on nickel electrodes. The G/CNTCs-MCs show impedance phase angle of -81.5° at a frequency of 120 Hz, comparable to commercial aluminum electrolytic capacitors (AECs) for alternating current (ac) line filtering applications. In addition, G/CNTCs-MCs deliver a high volumetric energy density of 2.42 mWh/cm(3) in the ionic liquid, more than 2 orders of magnitude higher than that of AECs. The ultrahigh rate capability of 400 V/s enables the microdevices to demonstrate a maximum power density of 115 W/cm(3) in aqueous electrolyte. The high-performance electrochemical properties of G/CNTCs-MCs can provide more compact ac filtering units and discrete power sources in future electronic devices. These elevated electrical features are likely enabled by the seamless nanotube/graphene junctions at the interface of the differing carbon allotropic forms.

Ultrahigh‐Power Pseudocapacitors Based on Ordered Porous Heterostructures of Electron‐Correlated Oxides

“…Unlike electrochemical double‐layer capacitors (EDLCs),8, 9, 10, 11, 12 in which charge storage is achieved by nonfaradaic electrostatic adsorption in nanostructured carbons with low intrinsic capacitance (≈20 μF cm −2 carbon ),1, 13, 14 pseudocapacitors store high‐density energy on pseudocapacitive materials by fast and reversible surface redox reactions at or near the electrode/electrolyte interface 1, 2, 3, 4, 5, 6, 7, 15, 16, 17. The surface mechanisms are fundamentally distinguished from rate‐limited volumetric reactions in batteries by short charge/discharge time, high power density and long‐term cycling stability 1, 2, 3, 18.…”

Strain and structure heterogeneity in MoS2 atomic layers grown by chemical vapour deposition

“…CVD-grown MoS 2 atomic layers are also superior to samples prepared by mechanical exfoliation and chemical isolation methods, as continuous monolayer MoS 2 (hereafter 1H-MoS 2 ) can currently be grown at the centimetre-length scale 3,11,17,18 . However, concurrently with the large-scale growth of monolayer MoS 2 , variations in crystal geometries and atomic structures have been predicted and observed 19 .…”

“…However, concurrently with the large-scale growth of monolayer MoS 2 , variations in crystal geometries and atomic structures have been predicted and observed 19 . Geometrically, MoS 2 triangles, hexagons, six-pointed stars, irregular shapes and continuous films can be synthesized, depending on the precise growth conditions such as pressure, temperature, substrates, precursors, cooling rate and so on [3][4][5]18,20 . Structurally, like graphene, a wide variety of grain boundaries (GBs) has been observed in polycrystalline CVDgrown MoS 2 (refs 3,4,21).…”

On‐Chip Micro‐Pseudocapacitors for Ultrahigh Energy and Power Delivery

“…In contrast to thin film batteries whose properties drop dramatically with the decrease of sizes, micro‐supercapacitors often have better performance in comparison with their bulk counterparts as the result of reduced transport length of charge and electrolytes 1, 2. Interdigital planar form micro‐supercapaciotors (MSCs) with active carbon,3 carbide‐derived carbon,4 carbon nanoparticles/nanotubes2, 5, 6, 7 and multilayer graphene7, 8, 9, 10, 11, 12, 13 as electrode materials have been developed and are capable of delivering high power density by electrochemical double layer charge storage. However, their energy densities, typically, 0.1–1.0 mW h cm −3 , are insufficient to meet the requirement of the reasonable operational time of microdevices.…”