Disassembly–Reassembly Approach to RuO₂/Graphene Composites for Ultrahigh Volumetric Capacitance Supercapacitor

Abstract

A porous, yet compact, RuO /graphene hybrid is successfully prepared by using a disassembly-reassembly strategy, achieving effective and uniform loading of RuO nanoparticles inside compact graphene monolith. The disassembly process ensures the uniform loading of RuO nanoparticles into graphene monolith, while the reassembly process guarantees a high density yet simultaneously unimpeded ion transport channel in the composite. The resulting RuO /graphene hybrid possesses a density of 2.63 g cm , leading to a record high volumetric capacitance of 1485 F cm at the current density of 0.1 A g . When the current density is increased to 20 A g , it remains a high volumetric capacitance of 1188 F cm . More importantly, when the single electrode mass loading is increased to 12 mg cm , it still delivers a high volumetric capacitance of 1415 F cm at the current density of 0.1 A g , demonstrating the promise of this disassembly-reassembly approach to create high volumetric performance materials for energy storage applications.

A combined approach for high-performance Li–O2 batteries: A binder-free carbon electrode and atomic layer deposition of RuO2 as an inhibitor–promoter

“…In addition to the cathode for Li-O 2 batteries, highly porous CNT-based electrodes modified with pseudocapacitive RuO 2 nanoparticles can find applications in supercapacitors. [43][44][45] See supplementary material for experimental details, Raman, TEM, TGA, and XPS data. …”

Nano‐RuO2‐Decorated Holey Graphene Composite Fibers for Micro‐Supercapacitors with Ultrahigh Energy Density

“…In comparison, pseudocapacitive materials store energy via reversible redox reactions at electrode–electrolyte interfaces, which may have 10–100 times higher specific capacitance than that of materials based on double‐layer capacitance alone . Therefore, significant research efforts have been devoted to incorporating various pseudocapacitive materials into graphene‐based fibers, including conductive polymers (e.g., poly(3,4‐ethylenedioxythiophene), poly(styrenesulfonate), polyaniline, and polypyrrole), transition metal oxides/hydroxides (e.g., RuO 2 , MnO 2 , MoO 2 , V 2 O 5 , Ni(OH) 2 , Co(OH) 2 ), and metal sulfides (e.g., NiCo 2 S 4 , MoS 2 ) . By bringing redox reactions into action, pseudocapacitive material‐incorporated electrodes go beyond the physical adsorption of ions and hence the energy storage capacity of overall structures usually get boosted.…”

“…Previous studies have shown that the addition of pseudocapacitive material precursors often significantly changes the ionic strength and/or pH of graphene or graphene oxide (GO) dispersions, which strongly affects the formation of structurally stable graphene fibers . Second, although increasing mass loading of pseudocapacitive materials in graphene fibers usually leads to higher total capacitance in composite fibers, it frequently causes extensive aggregation (of pseudocapacitive materials and precursors) and inefficient material usage . Third, high mass loading of pseudocapacitive materials also often block small pores in graphene fibers and hampers the diffusion of electrolytes, which lower the rate capability of resulting electrodes …”

Engineering Graphenes from the Nano- to the Macroscale for Electrochemical Energy Storage

“…There is enough pore space to ensure the fast ion diffusion when the dense RuO 2 /3D graphene is processed into a highmass-loaded electrode (12 mg cm −2 ), consequently giving an ultrahigh volumetric capacitance of 1415 F cm −3 in a H 2 SO 4 electrolyte (Fig. 9c) [87].…”

“…Copyright (2015) Wiley-VCH. c Illustration showing the disassembly-reassembly approach for synthesizing the RuO 2 /G composite [87]. Copyright (2017) Wiley-VCH partially fill the small spaces in the graphene network using disassembly-reassembly and capillary-drying approaches.…”