High-energy asymmetric electrochemical capacitors based on oxides functionalized hollow carbon fibers electrodes

Multi‐Anion Intercalated Layered Double Hydroxide Nanosheet‐Assembled Hollow Nanoprisms with Improved Pseudocapacitive and Electrocatalytic Properties

“…The SC performance of NiCo-LDHH NP was compared with recent reported NiCo-based electrodes in three-electrode system (Table S1), [15,18,19,35,36,42,[46][47][48][49][50][51][52] where one can find that NiCo-LDHH NP delivers av ery high specific capacitance and excellent rate and cycling performance, rendering it av ery promising electrode material for energy storagea pplication. This outstanding electrochemical performance should come from the combined effect of unique morphology of the nanosheet-assembled HNP and enlarged lamellar spacing of the LDH by multi-anion intercalation.…”

A High‐Energy Density Asymmetric Supercapacitor Based on Fe2O3 Nanoneedle Arrays and NiCo2O4/Ni(OH)2 Hybrid Nanosheet Arrays Grown on SiC Nanowire Networks as Free‐Standing Advanced Electrodes

“…The capacitance undergoes a slightly increase during the early 400 cycles, which is most likely ascribed to a fact that much more nanoarchitectures become activated caused by the consecutive permeation of electrolyte ions into the interior of the electrode materials. [11] Most noticeably, only 4.5% capacitance attenuation is observed after the device was charged and discharged 2000 cycles, and it still retains around 86.6% of its original specific capacitance even after 5000 cycles, suggesting an excellent cycling stability for the device that is preferable to other state-of-the-art ASC devices with various positive and negative electrodes, which are listed in Table S4 in the Supporting Information. Furthermore, the morphologies of the electrodes after 5000 cycles is also investigated by SEM technique ( Figure S11, Supporting Information).…”

“…Configuration of asymmetric supercapacitors (ASCs) has emerged as a desirable strategy because of the expanded V arised from the absolutely opposite potential window of the two dissimilar electrode materials. [10][11][12] Accordingly, considerable research interest has been invested in constructing highly capacitive negative and positive electrode materials.Until now, transition metal oxides, hydroxides, or phosphides, especially Ni-Co compounds with low cost, natural abundance, and environmentally benign, are mostly employed as positive electrode materials in ASCs because they can present variable oxidation states, favorable electrochemical activity, and large theoretical-specific capacitance based on redox reactions, so they have received extensive attentions as perfect candidates in ASCs. [13][14][15][16][17][18] However, in comparison of the extraordinary advancement obtained by positive electrode materials, the lack of desired negative electrodes restricts the progress of high-performance ASCs.…”

“…Configuration of asymmetric supercapacitors (ASCs) has emerged as a desirable strategy because of the expanded V arised from the absolutely opposite potential window of the two dissimilar electrode materials. [10][11][12] Accordingly, considerable research interest has been invested in constructing highly capacitive negative and positive electrode materials.…”

Macroscopic‐Scale Three‐Dimensional Carbon Nanofiber Architectures for Electrochemical Energy Storage Devices

“…The best way to solve this problem is constructing asymmetric supercapacitors by coupling different positive and negative electrode materials with well-separated potential windows, to acquire a high operation voltage, thereby achieving large energy and power densities. [223] Given this, many kinds of asymmetric supercapacitors are designed and constructed with 3D CNF architectures. We constructed an asymmetric supercapacitor (Figure 11a) containing a CNF gel coated with MnO 2 (CNF@ MnO 2 ) as the positive electrode prepared by redox at room temperature, and a nitrogen-doped CNF gel as the negative electrode, derived from CNF gel and urea with a facile hydrothermal reaction under mild conditions.…”