On-chip integrated vertically aligned carbon nanotube based super- and pseudocapacitors

Abstract

On-chip energy storage and management will have transformative impacts in developing advanced electronic platforms with built-in energy needs for operation of integrated circuits driving a microprocessor. Though success in growing stand-alone energy storage elements such as electrochemical capacitors (super and pseusocapacitors) on a variety of substrates is a promising step towards this direction. In this work, on-chip energy storage is demonstrated using architectures of highly aligned vertical carbon nanotubes (CNTs) acting as supercapacitors, capable of providing large device capacitances. The efficiency of these structures is further increased by incorporating electrochemically active nanoparticles such as MnOx to form pseudocapacitive architectures thus enhancing device capacitance areal specific capacitance of 37 mF/cm2. The demonstrated on-chip integration is up and down-scalable, compatible with standard CMOS processes, and offers lightweight energy storage what is vital for portable and autonomous device operation with numerous advantages as compared to electronics built from discrete components.

Homogeneous Fe2O3 coatings on carbon nanotube structures for supercapacitors

“…The values are also similar to those already reported in the literature (37 mF cm −2 ) for vertically oriented CNTs covered with metal oxide nanoparticles. 45 Other works present higher areal capacitance values (around 600 mF cm −2 ). 26 However, the nanotubes are not vertically aligned but rather randomly oriented and with a higher mass loading (30-50 mg cm −2 ).…”

Thermodynamic Stability of Nano-grained Alloys Against Grain Coarsening and Precipitation of Macroscopic Phases

“…[7a] and [7b] should be substituted into the right-hand side of Eq. [9] (r A ¼ r B ) and from here the equilibrium mole fraction of component B in the GB region is found (x gb ). Then, substituting this latter value back into Eqs.…”

“…To perform calculations with Eqs. [7] through [9] the following initial information must be known for the given A-B system:…”

“…These two later values must be equal, and according to Eq. [9] their values also equal the GB energy of the alloy (= solid solution).…”

“…NANO-MATERIALS play an increasing scientific and social role. [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19] In the past, nano-materials were simplified to single nano-particles. However, it has been clear for some decades that the real use of nanomaterials is expected if they form macroscopic articles with nano-structure inside.…”