Ultrastable Surface‐Dominated Pseudocapacitive Potassium Storage Enabled by Edge‐Enriched N‐Doped Porous Carbon Nanosheets

Xu, Fei; Zhai, Yixuan; Zhang, En; Liu, Qianhui; Jiang, Guangshen; Xu, Xiaosa; Qiu, Yuqian; Liu, Xiaoming; Wang, Hongqiang; Kaskel, Stefan

doi:10.1002/anie.202005118

Cited by 156 publications

(94 citation statements)

References 64 publications

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“…In the depotassiation, the peak of D bands was faded down, indicating that the original structure can be recovered after potassium ion desertion. [ 50–52 ] Meantime, the I D /I G ratios of the BN‐PC samples at different potassiation states increase upon discharging, and resume upon charging, demonstrating that the structure is nearly reversible. As displayed in Figure 5b, the EDS mapping results for the sample with a fully discharged state also exhibit that the K element distributes uniformly over the carbon matrix, further proving the successful intercalation of K‐ions into the BN‐PC electrode.…”

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

111

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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

111

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“…The K point mesh size with gamma point was selected for the irreducible first Brillouin zone integrations in the graphene fragment. Bader charge analysis [ 54 ] and partial charge density simulations were further conducted Zinc ion bonding with the functionalized graphene. The adsorption energy of Zinc ion was calculated by the below formula: E ads = E total − E fragment − E Zn , where E total and E fragment were the total energy with and without the adsorption of Zinc ion, E Zn is the energy of Zn atoms.…”

Section: Methodsmentioning

confidence: 99%

Regulating Oxygen Substituents with Optimized Redox Activity in Chemically Reduced Graphene Oxide for Aqueous Zn‐Ion Hybrid Capacitor

Shao

Sun

Tian

et al. 2020

Adv Funct Materials

138

100

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Functionalizing carbon cathode surfaces with oxygen functional groups is an effective way to simultaneously tailor the fundamental properties and customize the electrochemical properties of aqueous Zn‐ion hybrid capacitors. In this work, the oxygen functional groups of chemically reduced graphene oxide (rGO) are systematically regulated via a series of reductants and varied experimental conductions. Carboxyl and carbonyl have been proven to significantly enhance the aqueous electrolyte wettability, Zn‐ion chemical adsorption, and pseudocapacitive redox activity by experimental study and computational analysis. The rGO cathode produced through hydrogen peroxide assisted hydrothermal reduction exhibits a specific capacitance of 277 F g−1 in 1 m ZnSO4 after optimization of surface oxygen functional groups. In addition, a quasi‐solid‐state flexible Zn‐ion hybrid capacitor (ZHC) with a polyacrylamide gel electrolyte and a high loading mass of 5.1 mg cm−2 are assembled. The as‐prepared quasi‐solid state ZHC can offer a superior areal capacitance of 1257 mF cm−2 and distinguished areal energy density of 342 µW h cm−2. The significant enhancement of redox activity and Zn‐ion storage capability by regulating the oxygen functional groups can shed light on the promotion of electrochemical charge storage properties even beyond protic electrolyte systems.

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“…Recent years have witnessed the enormous endeavors devoted to exploring high-performance anodes for PIBs. Given the low cost and easy availability, carbon materials have been investigated, however, their theoretical specific capacity (278 mAh•g -1 ) remains unsatisfactory according to the formation of one-stage KC8 in graphite structure via the intercalation chemistry [10][11][12]. In contrast, materials involved in the conversion or alloying chemistry for K + storage are anticipated to provide much higher capacity, such as transition metal dichalcogenides (TMDs) [13,14] and phosphides (TMPs) [15,16].…”

Section: Introductionmentioning

confidence: 99%

Edge-enriched MoS2 for kinetics-enhanced potassium storage

Han

et al. 2020

Nano Res.

Self Cite

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Potassium-ion batteries (PIBs) hold great promise as alternatives to lithium ion batteries in post-lithium age, while face challenges of slow reaction kinetics induced by the inherent characteristics of large-size K +. We herein show that creating sufficient exposed edges in MoS 2 via constructing ordered mesoporous architecture greatly favors for improved kinetics as well as increased reactive sites for K storage. The engineered MoS 2 with edge-enriched planes (EE-MoS 2) is featured by three-dimensional bicontinuous frameworks with ordered mesopores of ~ 5.0 nm surrounded by thin wall of ~ 9.0 nm. Importantly, EE-MoS 2 permits exposure of enormous edge planes at pore walls, renders its intrinsic layer spacing more accessible for K + and accelerates conversion kinetics, thus realizing enhanced capacity and high rate capability. Impressively, EE-MoS 2 displays a high reversible charge capacity of 506 mAh•g −1 at 0.05 A•g −1 , superior cycling capacities of 321 mAh•g −1 at 1.0 A•g −1 after 200 cycles and a capacity of 250 mAh•g −1 at 2.0 A•g −1 , outperforming edge-deficient MoS 2 with nonporous bulk structure. This work enlightens the nanoarchitecture design with abundant edges for improving electrochemical properties and provides a paradigm for exploring high-performance PIBs.

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Ultrastable Surface‐Dominated Pseudocapacitive Potassium Storage Enabled by Edge‐Enriched N‐Doped Porous Carbon Nanosheets

Cited by 156 publications

References 64 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

Regulating Oxygen Substituents with Optimized Redox Activity in Chemically Reduced Graphene Oxide for Aqueous Zn‐Ion Hybrid Capacitor

Edge-enriched MoS2 for kinetics-enhanced potassium storage

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