Nature of improved double-layer capacitance by KOH activation on carbon nanotube-carbon nanofiber hierarchical hybrids

Yang, Zhen; Wang, Yu Hai; Dai, Zhe; Lu, Zhong Wei; Gu, Xiu Yun; Zhao, Hao; Sun, Geng Zhi; Lan, Wei; Zhang, Zhenxing; Pan, Xiao Jun; Zhou, Jin

doi:10.1016/j.carbon.2019.02.057

Cited by 48 publications

(18 citation statements)

References 53 publications

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“…[ 41 ] H 2 , CO, CO 2 , and vaporized H 2 O formed in the pyrolysis decomposing also contribute to the construction of the 3D hierarchical open‐type porous structure through gasification and gas interaction. [ 41–43 ] Meanwhile, the thermal decompositions of the ethylenediamine curing agents, triethanolamine accelerators and epichlorohydrin intermediates in the fluorinated epoxy resins result in the codoping of F, O, N, and Cl into HDGs graphene lattices, making it preferable with heteroatom activating defects as the heteroatom‐doping electronegative sites. As shown in Figure A–C, the atomic‐scale characterizations of these heteroatomic sites are evidently formed in HDGs graphene lattices.…”

Section: Resultsmentioning

confidence: 99%

Effectively Regulating More Robust Amorphous Li Clusters for Ultrastable Dendrite‐Free Cycling

Huang

Yang

et al. 2021

Advanced Science

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A disordered phase in Li-deposit nanostructure is greatly attractive, but plagued by the uncontrollable and unstable growth, and the nanoscale characterization in the structure. Here, fully characterized in cryogenic transmission electron microscopy (cryo-TEM), more robust amorphous-Li (ALi) clusters are revealed and effectively regulated on heteroatom-activating electronegative sites and an advanced solid electrolyte interphase (SEI) layer. Heteroatom-activating electronegative sites capably enhance the electrostatic interaction of Li + and heteroatom-doping graphene-like film (HDGs), meaning lower Li diffusion barrier and larger binding energy that is confirmed by small nucleation overpotentials of 13.9 and 10 mV at 0.1 mA cm −2 in the fluoroethylene carbonate-adding ester-based (FEC-ester) and LiNO 3 -adding ether-based (LiNO 3 -ether) electrolytes. Orderly multilayer SEI structure comprised of inorganic-rich components enables fast ion transports and durable capabilities to construct highly reversible and long-term plating/stripping cycling. ALi cluster anodes exhibit non-crystalline morphologies and perform ultrastable dendrite-free cycling over 2800 times. Stable ALi clusters are also grown in LiFePO 4 (LFP) (LFP-ALi-HDGs-N||LiFePO 4 [LFP]) full cells with advantageous capacities up to 165.5 and 164.3 mAh g −1 in these optimized electrolytes at 0.1 C; the remarkable capacity retentions maintain to 93% and 91% after 150 cycles at 0.2 C. Structure viability, electrochemical reversibility, and excellent performance in ALi clusters are effectively regulated.

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Section: Resultsmentioning

confidence: 99%

Effectively Regulating More Robust Amorphous Li Clusters for Ultrastable Dendrite‐Free Cycling

Huang

Yang

et al. 2021

Advanced Science

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“…Then, the MCCF material was ground into powder and added into 1.0 M KOH solution with a MCCF:KOH mass of 1:2 and stirred for 24 h; then, the mixed solution was dried to remove the water. After that, the dried mixture of MCCF/KOH was activated at 800 °C in N 2 atmosphere for 0.5 h. During this process, the reaction of “2 KOH + 2C → 2K + 2CO↑ + H 2 ↑” happened, leaving abundant pores in MCCF matrix [ 39 ]. Then, 1.0 M HCl aqueous solution was used to neutralize the extra KOH activation agent and react with K in the obtained product.…”

Section: Methodsmentioning

confidence: 99%

Homologous Strategy to Construct High-Performance Coupling Electrodes for Advanced Potassium-Ion Hybrid Capacitors

Ruan

Pang

et al. 2020

Nano-Micro Lett.

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Potassium-ion hybrid capacitors (PIHCs) have been considered as promising potentials in mid- to large-scale storage system applications owing to their high energy and power density. However, the process involving the intercalation of K+ into the carbonaceous anode is a sluggish reaction, while the adsorption of anions onto the cathode surface is relatively faster, resulting in an inability to exploit the advantage of high energy. To achieve a high-performance PIHC, it is critical to promote the K+ insertion/desertion in anodic materials and design suitable cathodic materials matching the anodes. In this study, we propose a facile “homologous strategy” to construct suitable anode and cathode for high-performance PIHCs, that is, unique multichannel carbon fiber (MCCF)-based anode and cathode materials are firstly prepared by electrospinning, and then followed by sulfur doping and KOH activation treatment, respectively. Owing to a multichannel structure with a large interlayer spacing for introducing S in the sulfur-doped multichannel carbon fiber (S-MCCF) composite, it presents high capacity, super rate capability, and long cycle stability as an anode in potassium-ion cells. The cathode composite of activated multichannel carbon fiber (aMCCF) has a considerably high specific surface area of 1445 m2 g−1 and exhibits outstanding capacitive performance. In particular, benefiting from advantages of the fabricated S-MCCF anode and aMCCF cathode by homologous strategy, PIHCs assembled with the unique MCCF-based anode and cathode show outstanding electrochemical performance, which can deliver high energy and power densities (100 Wh kg−1 at 200 W kg−1, and 58.3 Wh kg−1 at 10,000 W kg−1) and simultaneously exhibit superior cycling stability (90% capacity retention over 7000 cycles at 1.0 A g−1). The excellent electrochemical performance of the MCCF-based composites for PIHC electrodes combined with their simple construction renders such materials attractive for further in-depth investigations of alkali-ion battery and capacitor applications.

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“…Macromolecule cross‐linking‐assisted synthesis is also a promising method for creating gelation‐based 3D graphene or rGO structures . The traditional CVD method is a powerful technique to grow carbon nanostructures such as 3D nanorod arrays, nanotubes, and nanofibers . It has recently been demonstrated that graphene‐CNT integrated 3D nanomaterials with a pillared structure can be produced by single‐ or multistep CVD processes, and even through solution self‐assembly .…”

Section: Designing 3d Porous Carbons For Electrocatalysismentioning

confidence: 99%

3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis

Sobrido

Jervis

Periasamy

et al. 2019

Advanced Energy Materials

125

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Sustainable energy production at an acceptable cost is key for its widespread application. At present, noble metals and metal oxides are the most widely used for electrocatalysis, but they suffer from low selectivity, poor durability, and scarcity. Because of this, metal‐free carbons have become the subject of great interest as promising alternative electrocatalysts for energy conversion and storage devices, and remarkable progress has been accomplished in the advance of metal‐free carbons as electrocatalysts for renewable energy technologies. Particularly interesting are 3D porous carbon architectures, which exhibit outstanding features for electrocatalysis applications, including broad range of active sites, interconnected porosity, high conductivity, and mechanical stability. This review summarizes the latest advances in 3D porous carbon structures for oxygen and hydrogen electrocatalysis. The structure–performance relationship of these materials is consequently rationalized and perspectives on creating more efficient 3D carbon electrocatalysts are suggested.

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Nature of improved double-layer capacitance by KOH activation on carbon nanotube-carbon nanofiber hierarchical hybrids

Cited by 48 publications

References 53 publications

Effectively Regulating More Robust Amorphous Li Clusters for Ultrastable Dendrite‐Free Cycling

Effectively Regulating More Robust Amorphous Li Clusters for Ultrastable Dendrite‐Free Cycling

Homologous Strategy to Construct High-Performance Coupling Electrodes for Advanced Potassium-Ion Hybrid Capacitors

3D Carbon Materials for Efficient Oxygen and Hydrogen Electrocatalysis

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