Compressed and Crumpled Porous Carbon Electrode for High Volumetric Performance Electrical Double‐Layer Capacitors

Abstract

The 2D carbon sheets have great potential for the construction of compact electrodes with high volumetric performance for electrical double‐layer capacitors (EDLCs), by virtue of their excellent electrical conductivity, high exposed surface area, free of interpores, and unimpeded ion‐diffusion channels. However, 2D nanosheets restack and aggregate during the preparation processes of electrodes, reducing available surface area, and limiting transport of ions. Herein, a facile and scalable method is presented to prepare highly porous crumple carbon balls (PCCBs) assembled by 2D carbon nanosheets. Such a unique nanostructure endows the PCCB electrode with large electrolyte‐accessible surface area and short ion‐diffusion pathways even when compressed at 40 MPa. Electrochemical evaluations in 1‐ethyl‐3‐methylimidazolium tetrafluoroborate (EMIMBF4) electrolyte indicate that the compressed PCCB electrodes still show superior gravimetric (103 F g−1) and volumetric capacitances (127 F cm−3) at 1 A g−1. The highest volumetric energy density of symmetrical EDLC based on compressed PCCB‐based electrode is 53.9 Wh L−1. This work provides a new direction for the development of high volumetric energy density carbon‐based EDLCs.

Hierarchical Nanoporous C/C Composite from Humic Fulvic Acid and Sulfonated Pitch for High‐Energy‐Density EDLC Electrodes

“…The energy density of FASP10‐800 can reach up to 55.4 Wh kg −1 at power density of 87.5 W kg −1 and can still maintain 35.2 Wh kg −1 at high power density of 8.75 kW kg −1 , much better than that of AC. Satisfactorily, these values of FASP10‐800 can be compared with or even surpass many porous carbons in literature, as displayed in SI Table S4 [6,11,23,37–43] …”

“…As a kind of electrochemical energy storage system, EDLCs have attracted tremendous attention because of their high‐power density and fast charge/discharge rate, showing wide prospects in the fields of military and civil applications [1–6] . Nanoporous carbon is the mainstream material for EDLCs electrodes, owing to its high specific surface area (SSA), good electrochemical stability and low cost [7,8] .…”

Preparation of Nitrogen and Sulfur Co‐doped and Interconnected Hierarchical Porous Biochar by Pyrolysis of Mantis Shrimp in CO2 Atmosphere for Symmetric Supercapacitors

“…Consequently, in theory, the greatly improved microstructure and higher SSA, pore volume, pore diameter and other physical and chemical properties, can lead to a higher specific capacitance, which has been confirmed by many researchers. SSA of crumple carbon balls were increased from 58 to 266 m 2 g −1 with a particle size distribution centered around 3.4 nm and mesoporous structure, which is beneficial to the transport of organic electrolyte ions [16] . In the study of Cheng et al [17] .…”

A Low‐Temperature Dehydration Carbon‐Fixation Strategy for Lignocellulose‐Based Hierarchical Porous Carbon for Supercapacitors

“…The volumetric energy density of the devices was improved by adjusting the compaction density of electrode or the particle size of carbon powder. [24,25] In addition, increasing the working voltage (using organic electrolyte or ionic liquid) and developing asymmetric supercapacitors are also considered to be effective methods to improve the volumetric energy density of devices. [26][27][28][29] How to improve the volumetric energy density of lignocellulose-based porous carbons via changing their structural characteristics and density properties is still under development.…”

“…These methods usually sacrifice the conductivity or cycling stability of the material to some extent. The volumetric energy density of the devices was improved by adjusting the compaction density of electrode or the particle size of carbon powder [24,25] . In addition, increasing the working voltage (using organic electrolyte or ionic liquid) and developing asymmetric supercapacitors are also considered to be effective methods to improve the volumetric energy density of devices [26–29] .…”