Advancements and Challenges in Potassium Ion Batteries: A Comprehensive Review

Abstract

Demand for energy in day to day life is increasing exponentially. However, existing energy storage technologies like lithium ion batteries cannot stand alone to fulfill future needs. In this regard, potassium ion batteries (KIBs) that utilize K ions in their charge storage mechanism have attracted considerable attention due to their unique properties and are therefore established as one of the future battery systems of interest among the scientific community. Nevertheless, the development and identification of appropriate electrode materials is very essential for practical applications. This review features the current development in KIBs electrode and electrolyte materials, the present challenges facing this technology (in the commercial aspect), and future aspects to develop fully functional KIBs. The potassium storage mechanisms, evolution of the KIBs, and the advantages and disadvantages of each category of materials are included. Additionally, various approaches to enhance the electrochemical performances of KIBs are also discussed. This review is not only an amalgamation of different viewpoints in literature, but also contains concise perspectives and strategies. Moreover, the potential emergence of a novel class of K‐based dual ion batteries is also analyzed for the first time.

Organic Electrode Materials for Non-aqueous K-Ion Batteries

“…Interestingly, the electrochemical behavior of small-molecule ligands in MOFs can be enhanced under the influence of transition-metal cations [123]. For example, cobalt terephthalate (CoTP,No. 36) can deliver an abnormally high reversible capacity of up to 700 mA•h/g after 100 cycles in LIBs, whereas the specific capacity of terephthalate is 300 mA•h/g [124,125].…”

“…However, graphite is inadequate for practical application in KIBs. During insertion, K + suffers from severe volume charges, which is almost six times greater than the volume expansion during the insertion of Li + [36]. Meanwhile, alloying and conversion-type anodes suffer from serious volume expansion, causing the pulverization of materials [130,131].…”

“…On the contrary, organic electrode materials (OEMs) are assembled on the basis of van der Waals force rather than covalent/ionic bonding. Hence, a large interlayer spacing and flexible structure can be achieved in OEMs [36]. Therefore, OEMs that have been extensively researched for use in LIBs and NIBs may be also suitable for KIBs.…”

Emerging Potassium‐ion Hybrid Capacitors

“…Finally, remaining challenges and perspectives on further development of potassium-ion capacitors are put forward. a) The number of publications on potassium-ion batteries according to Web of Science with the Topic of "potassium-ion batteries" from 2005 to February of 2020, b) the distribution of element content in the crust, c) price comparison of lithium, sodium and potassium, [19,23,24] d) volumetric and gravimetric energy density of potassium-, lithium-and sodium-ion batteries. [2,22,25]…”

Unveiling the SEI Formation in a Potassium Ion Battery Using Distribution of Relaxation Time

“…7,8 In the case of PIBs, conversion-type electrodes possess faster reaction kinetics than intercalation-type electrodes, and have been spotlighted as interesting candidates for PIBs. 9,10 However, conversion reactions present signi cant volume changes during discharge and charge processes, resulting in the breakdown and reconstruction of SEI layer and further leading to massive side-reactions between electrolyte and electrode, depletion of electrolytes, and electrode passivation. 11,12 Therefore, a robust and high-quality SEI layer is crucial to endow conversiontype materials good electrochemical performance in PIBs.…”