Recent Developments and Future Challenges in Designing Rechargeable Potassium-Sulfur and Potassium-Selenium Batteries

Abstract

The use of chalcogenide elements, such as sulfur (S) and selenium (Se), as cathode materials in rechargeable lithium (Li) and sodium (Na) batteries has been extensively investigated. Similar to Li and Na systems, rechargeable potassium–sulfur (K–S) and potassium–selenium (K–Se) batteries have recently attracted substantial interest because of the abundance of K and low associated costs. However, K–S and K–Se battery technologies are in their infancy because K possesses overactive chemical properties compared to Li and Na and the electrochemical mechanisms of such batteries are not fully understood. This paper summarizes current research trends and challenges with regard to K–S and K–Se batteries and reviews the associated fundamental science, key technological developments, and scientific challenges to evaluate the potential use of these batteries and finally determine effective pathways for their practical development.

Recent Advances in Emerging Non‐Lithium Metal–Sulfur Batteries: A Review

“…Compared with Li/Na-S batteries, research on K-S batteries has emerged because of the low redox potential and abundant reserves of K. [149] However, K is much more reactive than its Li and Na counterparts, and the larger ionic size of K + also results in sluggish reaction kinetics, hindering the practical applications of K-S batteries. To resolve these obstacles, both sulfur cathodes and electrolytes require rational design.…”

Rechargeable Potassium–Selenium Batteries

“…[ 17 ] However, the large ionic radius of potassium ions imposes great limitations on their diffusion and intercalation in electrodes, leading to poor electrochemical performance of KIBs so far. [ 18 ] Commercial graphite is capable of storing potassium ions but shows low reversible specific capacity (279 mA h g −1 ) and sluggish reaction kinetics. [ 19 ] In order to tackle this problematic issue, considerable efforts have to be devoted to design of high‐capacity anode materials.…”

A Novel Cathode Based on Selenium Confined in Biomass Carbon and Graphene Oxide for Potassium‐Selenium Battery

“…[10,11] Se as cathode material still has many problems in the KÀ Se batteries system: (1) the large size of selenium limits the reaction of selenium with potassium; (2) the production of soluble intermediate polyselenides may lead to the shuttle effect, which rapidly decays the capacity; (3) appropriate electrolyte and electrode structure are supposed to be explored to improve material properties. [12,13] At present, researchers have used many methods to buffer the volume expansion and inhibit the shuttle effect of Se. For example, Sun's group reported that concentrated electrolyte could mitigate the dissolution and shuttle effect of potassium polysulfide in KÀ S batteries.…”

“…investigated electrochemical performance and reaction mechanism for K−Se and K−Te batteries, and identified the reaction pathways of K−Se batteries based on a carbon/Se composite cathode and a highly concentrated ether based electrolyte as reversible stepwise phase transformation from solid‐state Se to soluble K 2 Se 5 , and to solid‐state K 2 Se 3 , K 2 Se 2 , and K 2 Se [10,11] . Se as cathode material still has many problems in the K−Se batteries system: (1) the large size of selenium limits the reaction of selenium with potassium; (2) the production of soluble intermediate polyselenides may lead to the shuttle effect, which rapidly decays the capacity; (3) appropriate electrolyte and electrode structure are supposed to be explored to improve material properties [12,13] …”