High-performance potassium ion capacitors enabled by hierarchical porous, large interlayer spacing, active site rich-nitrogen, and sulfur Co-doped carbon

Fan, Binbin; Yan, Jiaxu; Hu, Aiping; Liu, Zheng; Li, Weize; Li, Yanhua; Xu, Yali; Zhang, Yan; Tang, Qunli; Chen, Xiaohua; Liu, Jilei

doi:10.1016/j.carbon.2020.03.035

Cited by 82 publications

(42 citation statements)

References 48 publications

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“…Even at the high power density of 12 000 W kg −1 , the BN‐PC//BN‐PC PIHC can still maintain a high energy density of 60 Wh kg −1 , which is comparable to previously reported carbon‐based asymmetrical PIHCs (Figure 7d). [ 16,58–63 ] Moreover, the BN‐PC//BN‐PC PIHC devices demonstrate an excellent cycling life. After 6000 cycles at 2 A g −1 , the device still delivers ≈78% capacity retention with only 0.0037% fading per cycle (Figure 7e), which hence exhibits the promising application prospect of the BN‐PC materials in energy storage devices.…”

Section: Resultsmentioning

confidence: 99%

Liquid‐State Templates for Constructing B, N, Co‐Doping Porous Carbons with a Boosting of Potassium‐Ion Storage Performance

Feng

Liu

et al. 2020

Advanced Energy Materials

132

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lithium resources greatly limits the large-scale promotion and application of LIBs. [4-7] As possible candidates, sodium and potassium ion systems are receiving intense attention owing to their low cost and high natural abundant resources. [8-14] Particularly, recent studies indicated that compared with sodium ions, potassium ions exhibited more merits on the basis of its similar intercalation behaviors in graphite and closer redox potential (K/K + , −2.92 V) with Li ions. [15,16] Therefore, potassium ion energy storage system, including potassium ion batteries (PIBs) and potassium ion hybrid capacitors (PIHCs) demonstrates a promising prospect in practical applications, and the corresponding studying upsurge is just beginning. [16,17] In the exploration of potassium electrode materials, porous carbons are highly preferable owing to their elastic framework, rich porosity and good conductivity, which can efficiently alleviate the volume expansion caused by the larger K + (ionic radius, 1.38 Å) intercalation and provides more pathways for fast K + diffusion. [16,18-21] So far, many carbons with various porosities have been successfully used in potassium ion system, exhibiting excellent electrochemical performance. [22,23] In current strategies of producing porous carbons, the template method is considered as one ideal way owing to its good control of porous architectures. [16] Presently, solid-phase templates including salts, SiO 2 nanospheres, and metal foams have been applied widely in constructing porous carbons. [24-26] Besides, gas-phase templates such as gas bubbles and foams are also popular due to their facile and economical process. [23,27] Despite a great process, several challenges still remain. For example, salt or gas-phase templates are simple and scalable, but always create large-size pores, giving rise to the severe decrease of the volumetric capacitance. [28] The nanosized solid-phase templates can lead to small-size pores, but are hindered by high cost and the probability of contamination from the removal process. [29] Therefore, the development of a scalable and green template strategy for the synthesis of carbons with rich nanosized porosity is important. Notably, in contrast to the success of solid-and gas-phase templates, liquid-state templates are rarely reported so far, which might be Template-assistant design and fabrication of porous carbon electrode materials has experienced great progress throughout the past decades and yielded lots of successes via various gas or solid state templates. Nevertheless, liquid-state templates are rather rare in preparing porous carbon materials to date. In this work, melting B 2 O 3 beads are used as both templates and a B dopant, leading to unique B, N co-doping hierarchically porous carbons containing a "bubble pool"-like skeleton built of interconnected carbon nanobubbles. Notably, an interesting amending effect of doped B atoms on the N-doped carbon network can be identified for the first time, which creates a "paddy field"-like hybrid microstructure wi...

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Section: Resultsmentioning

confidence: 99%

Liquid‐State Templates for Constructing B, N, Co‐Doping Porous Carbons with a Boosting of Potassium‐Ion Storage Performance

Feng

Liu

et al. 2020

Advanced Energy Materials

132

View full text Add to dashboard Cite

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“…Significant progresses have been achieved over the past few years, however, PIHCs are still far from satisfaction in terms of energy density at high power output. [ 8a,13 ] The key challenges lie in i) imbalanced kinetic behaviors between battery‐type anode and capacitor‐type cathode, resulting in limited energy‐power capabilities, and ii) underutilized cathode or anode originating from the mismatched charge/mass balance. Specifically, for the former one, the much larger ionic radius of K + (1.38 Å vs 0.76 Å of Li + , and 1.02 Å of Na + ) rises difficulty in terms of bulk‐diffusion of K + inside anode materials.…”

Section: Introductionmentioning

confidence: 99%

Optimized Kinetics Match and Charge Balance Toward Potassium Ion Hybrid Capacitors with Ultrahigh Energy and Power Densities

Peng

Zhang

Fan

et al. 2020

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Potassium ion hybrid capacitors (PIHCs) are of particular interest benefiting from high energy/power densities. However, challenges lie in the kinetic mismatch between battery‐type anode and capacitive‐type cathode, as well as the difficulty in achieving optimized charge/mass balance. These significantly sacrifice the electrochemical performance of PIHCs. Here, strategies including charge/mass balance pursuance, electrolyte optimization, and tailored electrode design, are employed, together, to address these challenges. The key parameters determining the energy storage properties of PIHCs are identified. Specifically, i) the good kinetic match between anode and cathode translates into the very small variation of cathode/anode mass ratio at various rates. This sets general rules for the pursuance of charge balance, and to maximize the electrochemical performance of hybrid devices. ii) A potassium bis(fluoroslufonyl)imide (KFSI)‐based electrolyte promotes better electrode kinetics and allows for the formation of more stable and intact solid electrolyte interphase layer, with respect to potassium hexafluorophosphate (KPF6)‐based electrolyte. And iii) hierarchically porous N/O codoped carbon nanosheets (NOCSs) with enlarged interlayer spacing, disordered structure, and abundant pyridinic‐N functional groups are advantageous in terms of high electronic/ionic transport dynamics and structural stability. All these together, contribute to the high energy/power density of the activated carbon//NOCSs PIHCs (113.4 Wh kg−1, at 17,000 W Kg−1).

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“…Besides, the reversible capacity and rate performance of N‐GQD@ASC‐500 are superior to previous reports about carbonaceous potassium‐ion battery anodes (Figure 3d). [ 21,22,25,28–34 ] Generally, the rate performance of the electrode is closely relevant to its electronic conductivity and ionic transport. The excellent rate performance of N‐GQD@ASC‐500 at high rates is attributed to the largest specific surface area with hierarchical micro‐meso‐macro‐porous structure and the enlarged interlayer distance that effectively facilitating the K + transport and the improved electronic conductivity after the adding of N‐doped GQDs as well.…”

Section: Resultsmentioning

confidence: 99%

Nitrogen‐Doped Accordion‐Like Soft Carbon Anodes with Exposed Hierarchical Pores for Advanced Potassium‐Ion Hybrid Capacitors

Zhang

Liu

et al. 2021

Adv Funct Materials

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Soft carbon (SC) is a promising anode material for potassium‐ion hybrid capacitors (PIHCs), but there are limited K+ storage sites in common SC due to a skin‐like carbon film covering on the surface. To address this issue, a simple oxidization method to completely remove the skin‐like carbon film is reported and a novel accordion‐like architecture of SC (ASC) is constructed with a hierarchical porous framework composed of micropores, mesopores, and macropores, all of which can be exposed to K+ electrolytes for enhanced energy storage. Importantly, this exposed structure facilitates pseudocapacitance modification by electro‐deposition of highly electrochemically active nitrogen‐doped graphene quantum dots (N‐GQDs) to enhance kinetic performance and additional K+ storage. After annealing treatment to regulate N‐doping type, the accordion‐like N‐GQD@ASC‐500 exhibits excellent reversible capacity of 360 mAh g−1 as well as superior rate capability and cycle stability. Kinetic, in situ Raman/electrochemical impedance spectroscopy analysis, and density functional theory calculation elucidate the K+ storage mechanism. As expected, the PIHC assembled with N‐GQD@ASC‐500 anode and porous carbon cathode delivers an ultrahigh energy/power density (171 Wh kg−1 and 20 000 W kg−1) with long cycle life. This work suggests that ASC is a promising anode material for designing of high‐performance PIHCs.

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High-performance potassium ion capacitors enabled by hierarchical porous, large interlayer spacing, active site rich-nitrogen, and sulfur Co-doped carbon

Cited by 82 publications

References 48 publications

Liquid‐State Templates for Constructing B, N, Co‐Doping Porous Carbons with a Boosting of Potassium‐Ion Storage Performance

Liquid‐State Templates for Constructing B, N, Co‐Doping Porous Carbons with a Boosting of Potassium‐Ion Storage Performance

Optimized Kinetics Match and Charge Balance Toward Potassium Ion Hybrid Capacitors with Ultrahigh Energy and Power Densities

Nitrogen‐Doped Accordion‐Like Soft Carbon Anodes with Exposed Hierarchical Pores for Advanced Potassium‐Ion Hybrid Capacitors

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