Asymmetric Carbon Nanohorn Enabled Soft Capacitors with High Power Density and Ultra‐Low Cutoff Frequency

Abstract

Flexible capacitors are a promising power source for foldable and biological electronic devices. Although various materials and device structures have been explored, they are still limited by low energy densities and slow rate capabilities compared to their rigid counterparts. Here, asymmetric carbon nanohorns are proposed as an active material to fabricate flexible solid‐state carbon wire (CW)‐based electrochemical supercapacitors (ss‐CWECs) which exhibit high power density and ultra‐low cutoff frequency. By controlling the electric arc reaction at low temperature (77 K), asymmetric single‐wall carbon nanohorns (SWCNHs) are synthesized with high yield. Based on microscopy and electrochemical characterization, the fundamental reaction mechanism in polyvinyl‐based electrolyte system is elucidated, as being associated with deprotonation reaction at acid, base, and elevated temperature conditions. Additionally, by using activated carbon, multi‐walled carbon nanotubes, and SWCNHs as hybrid electrode materials (5:1:1), remarkable specific length capacitance of 48.76 mF cm−1 and charge–discharge stability (over 2000 times cycles) of ss‐CWECs are demonstrated, which are the highest reported to date. Furthermore, a high‐pass filter for eliminating ultra‐low electronic noise is demonstrated, which enables an optical Morse Code communication system to be operated. Current results confirm the SWCNHs as promising materials for high‐performance soft electronics and energy storage applications.

Density-Induced Joule-Heating Characteristics of Nanocarbon Aerogels: Implications for Tunable Electrothermal Behaviors

“…Nanocarbon materials are becoming increasingly popular due to their remarkable physicochemical attributes, such as high surface area, good aspect ratio, superlative conductivity, impressive mechanical strength, outstanding thermal stability, and chemical inertness. − With these exceptional functional capabilities, this class of materials also showcases a wide range of dimensional variations, including fullerene, carbon nanohorn, , carbon nanotube, , graphene, − and graphitized nanofiber (GNF), , making them versatile for a broad spectrum of applications in emerging fields such as sensing, catalysis, environmental remediation, water generation, energy storage, and superconductors . An especially exciting attribute of nanocarbon materials is their ability to be assembled into three-dimensional (3D) nanocarbon aerogels through a variety of methods (e.g., hydrothermal method and polymer-assisted cross-linking method) to create highly porous and ultralight-weight bulk materials …”

Hollow Graphene as an Expansion-Inhibiting Electrical Interconnector for Silicon Electrodes in Lithium-Ion Batteries

“…The conductive agent used to secure electrical conducting pathways in a silicon electrode may be also exploited as a buffer phase to suppress dimensional changes upon repeated lithiation and delithiation. However, nano-sized carbon black particles, which conventionally used conductive agents for silicon electrodes, cannot maintain the electrical pathways and the initial microstructures of silicon electrodes against the volume expansion of silicon during cycling. , Although a lot of carbon materials with various nanostructures as conductive agents for lithium-ion batteries have been reported, − to the best of our knowledge, few reports have been published on conductive agents that can act as physical buffers in silicon electrodes. Given that the science and technology of carbon materials has flourished in recent decades, − it is likely that a variety of nanostructured carbon materials can offset mechanical and electrical degradation of silicon electrodes associated with volume changes of silicon during cycling.…”

Eu3+-functionalized CQD hybrid material: synthesis, luminescence properties and sensing application for the detection of Cu2+

“…Carbon dots have been used in various aspects, including cell imaging 6 , fluorescent ink 7 , photocatalysis [8][9] , drug delivery 10 , ion detection [11][12][13][14][15][16][17] , energy storage 18 and optoelectronics 19 . However, the lower fluorescence quantum yields and the singleness of CQDs sensors have limited their practical applications.…”