Design and Fabrication of Printed Paper‐Based Hybrid Micro‐Supercapacitor by using Graphene and Redox‐Active Electrolyte

Abstract

Inspired by future needs of flexible, simple, and low-cost energy storage devices, smart graphene-based micro-supercapacitors on conventional Xerox paper substrates were developed. The use of redox-active species (iodine redox couple) was explored to further improve the paper device's performance. The device based on printed graphene paper itself already had a remarkable maximum volumetric capacitance of 29.6 mF cm (volume of whole device) at 6.5 mA cm . The performance of the hybrid electrode with redox-active potassium iodide at the graphene surface was tested. Remarkably, the hybrid device showed improved volumetric capacitance of 130 mF cm . The maximum energy density for a graphene+KI device in H SO electrolyte was estimated to be 0.026 mWh cm . Thus, this work offers a new simple, and lightweight micro-supercapacitor based on low-cost printed graphene paper, which will have great applications in portable electronics.

Tungsten Nitride Nanodots Embedded Phosphorous Modified Carbon Fabric as Flexible and Robust Electrode for Asymmetric Pseudocapacitor

“…The τ 0 value of W 2 N@P‐CF//PPy@CF device was calculated to be 142 ms (for the corresponding frequency of 7 Hz and 87 ms from Bode plot at 11.5 Hz) as displayed in Figure e. This small τ 0 value for the W 2 N@P‐CF//PPy@CF cell is far better than the values reported for fast‐charging SCs in literature: RuO 2 //Ti 3 C 2 T x asymmetric cell (740 ms) and symmetric cells based on activated carbon (700 ms), reduced graphene oxide (430 ms), hybrid graphene (392 ms), and printed graphene modified potassium iodide symmetric cell (200 ms) . These results strongly suggest that our W 2 N@P‐CF//PPy@CF holds a great promise to offer simultaneously high energy and high power densities.…”

True Meaning of Pseudocapacitors and Their Performance Metrics: Asymmetric versus Hybrid Supercapacitors

“…[ 25,23 ] The Helmholtz model is the simplest model to describe this process as double‐layer capacitance using the equation for a parallel plate capacitor where C is the double‐layer capacitance, ε is the permittivity of the dielectric separating the charges, A is the surface area of the electrode, and d is the distance between the electrode and electrolyte ions. Typically, carbon‐based porous materials such as activated carbon, [ 26–28 ] xerogels, [ 29–32 ] carbon nanotubes (CNTs), [ 33–35 ] carbon nanofibers (CNFs), [ 36–38 ] graphene, [ 39–41 ] and carbide‐derived carbons [ 42–44 ] show EDLC type behavior owing to their high specific surface area and good conductivity. The charge/discharge process in EDLCs is associated with the purely non‐Faradaic reactions; thus, responds immediately to potential changes.…”

Graphene‐Based Planar Microsupercapacitors: Recent Advances and Future Challenges

“…Recently, Nagar et al introduced the redox pair I − /I 3 − into electrolytes by adding KI into H 2 SO 4 based electrolyte. The as‐fabricated paper‐based graphene MSC generated enhanced performance with an outstanding volumetric performance of 29.6 mF cm −3 under the current density of 6.5 mA cm −3 . However, the energy stored is limited by the narrow working voltage range of about 1 V due to the low decomposition voltage of water (1.23 V) .…”