Density and porosity optimization of graphene monoliths with high mass‐loading for high‐volumetric‐capacitance electrodes

Abstract

Improving the volumetric capacitance of graphene materials for supercapacitors without sacrificing their rate capability, especially at high mass‐loading, is a challenge because of the sluggish electrochemical kinetics of compact graphene electrodes. Here, a compact graphene monolith (dense graphene ribbons [DGRs]‐0.6) was fabricated by using graphene oxide ribbons as building blocks and deliberately harmonizing the graphene primitive unit structure and interlayer spacing. The DGRs‐0.6 contained abundant oxygen‐containing functional groups and a highly interconnected pore structure, resulting in a large ion‐accessible surface area, a high packing density, and fast electron/ion transport pathways. The DGRs‐0.6 electrode exhibited a volumetric capacitance of 316 F cm–3, a rate capability of 220 F cm–3 at 100 A g–1, and ultralong cycling stability. For a mass loading of 11 mg cm−2, the DGRs‐0.6 delivered volumetric capacitances of 150 F cm−3 at 1 A g−1 and 109 F cm−3 at 50 A g−1. The good rate capability and volumetric capacitance of DGRs‐0.6 under high mass loading demonstrate its potential as a supercapacitor electrode for practical applications.

Emulsion‐assisted interfacial polymerization strategy: Controllable architectural engineering of anisotropic and isotropic nanoparticles for high‐performance supercapacitors

“…The electrode provides a good electron and ion transfer pathway for the interface, which can be expected to a great application potential in practical energy storage. In addition, NPCPs‐0.4 exhibits excellent high‐rate and long‐term cycling stability 56–59 . The GC curves and specific capacitance keep almost unchanged over 4000 cycles at the current density of 5 A g −1 (Figure 5D).…”

“…In addition, NPCPs-0.4 exhibits excellent high-rate and long-term cycling stability. [56][57][58][59] The GC curves and specific capacitance keep almost unchanged over 4000 cycles at the current density of 5 A g −1 (Figure 5D). NPCPs are expected to be promising superior electrochemical materials, of which the microporous structure, beneficial nitrogen doping, and unique anisotropic large single-cavity features play a synergistic role in improving the properties of the materials.…”

High Mass‐Loading Biomass‐Based Porous Carbon Electrodes for Supercapacitors: Review and Perspectives

“…Under the conditions of meeting the commercial-level mass-loading (≈10 mg cm −2 ), the electrodes expose certain drawbacks, such as poor charging dynamics, poor electrode structural stability, complex and expensive production processes. [3,153] This subsection focuses on the important performance evaluation indicators of supercapacitors under commercial-level mass-loading. By analyzing the performance influencing factors, effective strategies for optimizing the electrochemical performance of high massloading carbon electrode materials are summarized, including the structure regulation of electrode materials and the optimization of other supercapacitor components.…”

Carbon Nanomaterials‐Enabled High‐Performance Supercapacitors: A Review

“…Introducing materials like metal or metal oxide nanoparticles, CNTs, and CNFs between graphene layers is one of the prospective strategies. [166][167][168][169][170][171][172] Salarizadeh et al [173] prepared cerium oxide/rGO (CeO 2 /rGO) composite via hydrothermal method, which yielded a specific capacitance of 581 F g À1 at a scan rate of 10 mV s À1 in KOH electrolyte with an excellent cycling stability of 91% after over 5000 cycles. The satisfactory electrochemical properties were due to the intercalation of CeO 2 nanoparticles between rGO flakes, which not only promoted the transmission of electrolyte ions but also provided electroactive sites for the Faradic process.…”