A Simple Approach towards Highly Dense Graphene Films for High Volumetric Performance Supercapacitors

Abstract

An interface self‐assembly followed by hydrothermal reduction method are proposed to obtain a tannic acid (TA)‐modified reduced graphene oxide composite film (|TA/RGO|). This unique method endows |TA/RGO| with several advantages: (1) TA is adopted as a redox‐active spacer between adjacent interlayers for enlarging the ion‐accessible area and contributing to pseudocapacitance; (2) due to the intensive pressure exerted by the sandwich‐like device during the hydrothermal reduction process, appropriate expansion and a relatively flat layered structure are achieved which will facilitate the ion transport. As a result, the |TA/RGO| film shows an ultrahigh volumetric performance of 701 F cm−3 with a high density of 1.91 g cm−3 using a three‐electrode system. When assembled into a symmetric supercapacitor, |TA/RGO| film delivers a high volumetric capacitance of 244.8 F cm−3 and a high capacitance retention of 100 % after 5000 cycles at the current density of 2 A g−1, showing a great potential for large‐scale application.

Application of Graphene Nanoplatelets in Supercapacitor Devices: A Review of Recent Developments

“…In addition to compositing carbon materials with pseudocapacitors, it is possible to create all-carbon composites by embedding carbon nanomaterials into a carbonaceous backbone [ 8 , 64 , 70 , 102 , 103 , 104 , 105 ]. For example, embedding carbon quantum dots into the pores of activated carbon can lead to a specific capacitance three times higher than that of unmodified activated carbon [ 106 ].…”

Electrochemically Exfoliated Layered Carbons as Sustainable Anode Materials for Lead Carbon Hybrid Ultracapacitor

“…[4][5][6][7][8] Besides, carbon-based hybrid supercapacitors are expected to find broad applications as they bridge the gap between high-powered electrochemical capacitors (ECs) and batteries that delivers high energy. [4][5][6][7][8][9][10][11][12][13][14] Like Li-ion hybrid supercapacitors, Lead-carbon hybrid ultracapacitors (PbÀ C HUC) are attracting wide research attention due to their long-life cycle (> 1,00,000) and high-power density (> 800 W Kg À 1 ) as compared to leadacid batteries (LABs) (cycle life: 500-1000 deep-discharge cycles). [15][16][17][18] Unlike Li/Na-hybrid supercapacitors, PbÀ C HUC is the most cost-effective aqueous-based system with > 98 % recyclability (sustainable).…”