Carbon Paper as Current Collectors in Graphene Hydrogel Electrodes for High-Performance Supercapacitors

Abstract

Current collectors are an important component of electrodes, functioning as conductive media by collecting currents from active materials and then exporting them to the external circuit. Common current collectors for graphene hydrogel (GH)-based supercapacitors are nickel foams or metal foils (platinum, gold, and aluminium, etc.). Here, hydrothermally synthesized GH was directly pressed on carbon paper and used as electrodes (denoted as GHE) for supercapacitors. With a mass loading of 2.7 mg·cm−2 at an active area of 0.64 cm2, the GHE-based supercapacitors revealed a high gravimetric capacitance of 294 F·g−1 at a current density of 1.18 A·g−1. When increasing the current density to 28.24 A·g−1, 66% (193 F·g−1) of the initial capacitance was maintained for the GHE-based supercapacitors. High performance for GHE-based supercapacitors was attributed to large specific surface area and good electrical conductivity of GH, and its intimate contact with carbon paper.

Status and Opportunities of Zinc Ion Hybrid Capacitors: Focus on Carbon Materials, Current Collectors, and Separators

“…As an inactive part of the ZIHC, current collectors do not contribute charge storage. Their main function is to carry active materials, collect current, and conduct electrons to the external circuit [ 190 ]. During the charge and discharge processes, side reactions of the inorganic salt in the aqueous electrolyte would corrode the current collector.…”

Synthesis and Electrochemical Study of Three-Dimensional Graphene-Based Nanomaterials for Energy Applications

“…To overcome the aggregation issues, various strategies have been proposed toward the development of macroscopic 3D structures—for instance, the introduction of functional groups or spacers [ 21 ], use of interconnecting graphene sheets [ 15 ], and the deposition of 3D architectures [ 22 ]. Recently, 3D graphene-based architectures such as hydrogels [ 23 , 24 ], aerogels [ 25 , 26 ], foams [ 27 , 28 ], and sponges [ 29 ] have been reported in the literature. Apart from structural stability, these 3D architectures exhibited high electrical conductivity and improved heterogeneous electron transfer properties due to the interconnectivity of graphene sheets [ 30 ].…”