Emerging organic potassium-ion batteries: electrodes and electrolytes

Abstract

<p>The progress and challenges of the electrodes and electrolytes in organic potassium-ion batteries are summarized.</p>

Challenges and Strategies toward Cathode Materials for Rechargeable Potassium‐Ion Batteries

“…Such functional groups are considered as "intentional" electrochemically-inactivate groups. [217] Enolate has the advantage of a lower molecular weight compared with the abovementioned sulfonate, and therefore is beneficial in achieving a higher theoretical capacity. For example, the two OK groups of K 2 C 6 O 6 can "intentionally" deactivate the electrochemistry by controlling the cutoff voltage to lower the solubility of K 2 C 6 O 6 .…”

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

“…[1] In the light of promoting efficient, safe, and low-polluting electrochemical energy storage systems, [2] electroactive organic materials (EOMs) have sparked considerable attention in recent compounds, [53] and the most recently reported N-substituted salts of viologen derivatives. [52] Since 2008 (a year witnessed as the modern area revival of EOMs), dozens of review articles have been published from different perspectives (e.g., molecular design, [20,22,23,27,41,42,49,50,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69] sustainability, [70,71] opportunity, [3,[72][73][74] practicability, [75][76][77][78] and technology [79][80][81][82] ). It is worth noting that most reviews are focused on OPEMs with less consideration to ONEMs, except two reviews dedicated to ONEMs for Na/K-ion batteries, [37,83] yet presenting only a summary of advances and no critical discussion or suggested solutions for remai...…”

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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.

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State-of-the-art anodes of potassium-ion batteries: synthesis, chemistry, and applications

“…Organic anodes with several advantages, such as tunable redox properties, low weight, and mechanical flexibility, could effectively expand the range of choices for KIB battery fabrication. 156 Moreover, the redox reactions of organic active materials are less hindered by the large ionic size of K ions owing to their soft nature, which has attracted considerable attention. An organic compound, azobenzene-4,4-dicarboxylic acid potassium salts (ADAPTS), was developed by Wang et al by neutralizing the azobenzene-4,4-dicarboxylic acid with potassium hydroxide, wherein the introduced carboxylate groups could remarkably minimize the dissolution of ADAPTS in organic electrolytes, as the polarity of the organic active materials was rationally enhanced.…”