Research Development on K-Ion Batteries

Abstract

Li-ion batteries (LIBs), commercialized in 1991, have the highest energy density among practical secondary batteries and are widely utilized in electronics, electric vehicles, and even stationary energy storage systems. Along with the expansion of their demand and application, concern about the resources of Li and Co is growing. Therefore, secondary batteries composed of earth-abundant elements are desired to complement LIBs. In recent years, K-ion batteries (KIBs) have attracted significant attention as potential alternatives to LIBs. Previous studies have developed positive and negative electrode materials for KIBs and demonstrated several unique advantages of KIBs over LIBs and Na-ion batteries (NIBs). Thus, besides being free from any scarce/ toxic elements, the low standard electrode potentials of K/K + electrodes lead to high operation voltages competitive to those observed in LIBs. Moreover, K + ions exhibit faster ionic diffusion in electrolytes due to weaker interaction with solvents and anions than that of Li + ions; this is essential to realize high-power KIBs. This review comprehensively covers the studies on electrochemical materials for KIBs, including electrode and electrolyte materials and a discussion on recent achievements and remaining/emerging issues. The review also includes insights into electrode reactions and solid-state ionics and nonaqueous solution chemistry as well as perspectives on the research-based development of KIBs compared to those of LIBs and NIBs.

Could K+‐Based Electrolytes Be the Reliable Environmental‐Friendly Alternative to Li+ in Gr//LMO Battery We Searched for?

“…The transport properties of electrolytes containing potassium salts according to more than 239 publications have been synthesized by Komaba and coworkers et al [ 40 ] and classified by the type of system or by the nature of solvent and anion of the salt. It shows that the most commonly used salt for all these K applications was KPF 6 , ≈80% of the studies on positive and negative electrodes for KIBs, because KPF 6 has several advantages such as electrochemical stability and passivation of Al foil.…”

Cucurbit[6]uril‐Derived Nitrogen‐Doped Hierarchical Porous Carbon Confined in Graphene Network for Potassium‐Ion Hybrid Capacitors

“…[5][6][7] Among them, potassium-ion hybrid capacitors (PIHCs) exhibit broader economic prospects due to the profuse natural abundance of potassium and the similar reduction potential and physical properties of potassium and lithium. [8][9][10][11][12][13][14][15] However, PIHCs suffer from severe kinetics failures and cyclability dilemmas since the large ionic size of K + (1.38 Å). [10,[13][14][15] In the view of PIHCs system, the anode side based on sluggish battery-type reactions is the short-board to achieve high-performance PIHCs.…”

“…[8][9][10][11][12][13][14][15] However, PIHCs suffer from severe kinetics failures and cyclability dilemmas since the large ionic size of K + (1.38 Å). [10,[13][14][15] In the view of PIHCs system, the anode side based on sluggish battery-type reactions is the short-board to achieve high-performance PIHCs. [8,9,11] Heteroatom-doped porous carbon (HDPC) with tunable porosity, abundant electron-donating heteroatoms, excellent chemical stability, and amorphous carbon framework has been exhibiting promising application prospects in many emerging fields such as energy storage/conversion, catalysis, biomedicine, and gas capture/separation.…”

Mixed Polyanionic Compounds as Positive Electrodes for Low‐Cost Electrochemical Energy Storage

“…This Minireview focuses on mixed polyanionic compounds (MPCs) as cathodes solely. Readers interested in conventional oxide or simple polyanionic compounds as positive electrodes should refer to relevant liturature . The subjects of this overview are the previously well‐identified polyanions in electrode materials, including borate, carbonate, oxalate, nitrate, silicate, phosphate, phosphite, and pyrophosphate, and sulfate and pyrosulfate, as well as halogen ions (X).…”