Organic Materials as Electrodes in Potassium‐Ion Batteries

Zhang, Weisheng; Huang, Weiwei; Zhang, Qichun

doi:10.1002/chem.202005259

“…Lithium-ion batteries have been widely utilized as power sources in portable devices and electric vehicles by virtue of their long-term cycle life and high energy densities. − However, they gradually cannot meet the demand of the burgeoning society for low-cost and large-scale energy storage systems owing to the uneven distribution and scarcity of lithium sources. Therefore, tremendous attention has been paid to developing new energy storage technologies. , In the past few years, potassium-ion batteries (PIBs) have been considered as one of the most promising candidates because of their similar properties to lithium-ion batteries and the natural abundance of potassium. − Nevertheless, the relevant studies are insufficient in such an emerging field; developing suitable anode materials with superior electrochemical performance and competitive cost is of paramount importance. , …”

Section: Introductionmentioning

confidence: 99%

Carbon-Free Crystal-like Fe_1–xS as an Anode for Potassium-Ion Batteries

Xu

¹

,

Wang

²

,

Hao

³

et al. 2021

ACS Appl. Mater. Interfaces

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Potassium-ion batteries (PIBs) as a new electrochemical energy storage system have been considered as a desirable candidate in the post-lithium-ion battery era. Nevertheless, the study on this realm is in its infancy; it is urgent to develop electrode materials with high electrochemical performance and low cost. Iron sulfides as anode materials have aroused wide attention by virtue of their merits of high theoretical capacities, environmental benignity, and cost competitiveness. Herein, we constructed carbon-free crystal-like Fe 1−x S and demonstrated its feasibility as a PIB anode. The unique structural feature endows the prepared Fe 1−x S with plentiful active sites for electrochemical reactions and short transmission pathways for ions/electrons. The Fe 1−x S electrode retained capacities of 420.8 mAh g −1 after 100 cycles at 0.1 A g −1 and 212.9 mAh g −1 after 250 cycles at 1.0 A g −1 . Even at a high rate of 5.0 A g −1 , an average capacity of 167.6 mAh g −1 was achieved. In addition, a potassium-ion full cell is assembled by employing Fe 1−x S as an anode and potassium Prussian blue as a cathode; it delivered a discharge capacity of 127.6 mAh g −1 at 100 mA g −1 after 50 cycles.

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“…

Thanks to their versatility and flexibility, EOMs have shown broad applicability as bulky solid [3] or dissolved [4,5] active material, in aqueous [6][7][8] or non-aqueous electrolyte, [9][10][11] for portable and stationary batteries, respectively. In practice, OEMs are explored as main active materials in LIBs, [12] beyond Li systems (e.g., hydrogen, [13,14] Na-ion, [15][16][17][18][19] K-ion, [20][21][22][23][24] and multivalent batteries like magnesium, [25,26] zinc, [27] or aluminum [28,29] ) and also redox flow batteries; [30] or as supporting active materials such as redox mediators for Li-O 2 batteries, [31] Li-source sacrificial materials for Li-ion capacitor [32] and redox electrolytes for high-energy supercapacitors. [33] In contrast to the state-of-the-art inorganic materials, whose reactivity is based on redox of transition metal center and consequently Li + de/insertion, [34,35] the redox reaction of EOMs is based on the charge state change of the redox moiety, [12] for which the charge compensation during redox can be either made by cations, referring to n-type systems, or by anions, belonging then to p-type system, according to the proposed Hünig's classification.

…”

mentioning

confidence: 99%

Organic Negative Electrode Materials for Metal‐Ion and Molecular‐Ion Batteries: Progress and Challenges from a Molecular Engineering Perspective

Lakraychi

¹

,

Dolhem

²

,

Vlad

³

et al. 2021

Advanced Energy Materials

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Thanks to their versatility and flexibility, EOMs have shown broad applicability as bulky solid [3] or dissolved [4,5] active material, in aqueous [6][7][8] or non-aqueous electrolyte, [9][10][11] for portable and stationary batteries, respectively. In practice, OEMs are explored as main active materials in LIBs, [12] beyond Li systems (e.g., hydrogen, [13,14] Na-ion, [15][16][17][18][19] K-ion, [20][21][22][23][24] and multivalent batteries like magnesium, [25,26] zinc, [27] or aluminum [28,29] ) and also redox flow batteries; [30] or as supporting active materials such as redox mediators for Li-O 2 batteries, [31] Li-source sacrificial materials for Li-ion capacitor [32] and redox electrolytes for high-energy supercapacitors. [33] In contrast to the state-of-the-art inorganic materials, whose reactivity is based on redox of transition metal center and consequently Li + de/insertion, [34,35] the redox reaction of EOMs is based on the charge state change of the redox moiety, [12] for which the charge compensation during redox can be either made by cations, referring to n-type systems, or by anions, belonging then to p-type system, according to the proposed Hünig's classification. [36,37] The richness of organic chemistry coupled with molecular modifications have provided thus far a plethora of molecules and architectures operating within a large potential window with high specific capacities, extended cycling stability and high cycling rate. This has enabled building a broad database of electroactive compounds for both positive and negative electrode applications. Organic positive electrode materials (OPEMs) certainly benefit from larger attention since there are more possibilities to explore, for example, conducting polymers, [38,39] nitroxides, and other stable organic radicals, [40][41][42][43] sulfur compounds, [11] as well as conjugated amines, [44][45][46] conjugated sulfonamides, [47] nitro-aromatics, [48] and carbonyls. [49,50] The latter being certainly the most explored category owing to major advances attained so far but also to opportunities for further improvements to attain simultaneously high energy and power densities combined with good cycling stability. [12] On the opposite side, the chemical library is less rich for organic negative electrode materials (ONEMs), primarily due to much focus on positive electrode chemistries, for which many issues and strategies are to be addressed and explored, respectively. Today, the ONEMs database counts fewer redox families as OPEMs one, with also less specific chemistries within each class. To cite some: the most studied conjugated dicarboxylates, [51] Hückel-stabilized Schiff base, [52] nitrogen-redox azo

show abstract

“…conductivity, which signicantly hinder the use of organic materials in electrochemical K storage. [79][80][81] For instance, potassium 1,1-biphenyl-4,4-dicarboxylate (K 2 BPDC) and potassium 4,4-E-stilbenedicarboxylate (K 2 SBDC) exhibited capacity fading even at a low current density due to their solubility in the electrolyte of 1 M potassium bis(uorosulfonyl)amide (KFSI) in ethylene carbonate and dimethyl carbonate (EC : DMC). 79 The dissolution of organic materials in electrolytes can be visually observed from the colour change of the electrolyte, as seen from the dissolution of Calix [4]quinone turning the colourless dimethoxyethane (DME) solvent to yellow over a period of time (Fig.…”

Section: Alloying-based Metal Hybrid Nanostructuresmentioning

confidence: 99%