A recent review showed currently that several pragmatic materials have been successfully used as the anode and cathode for the new generations of potassium-ion batteries.
After the invention of potassium-ion battery with the prototype device, researchers have increasingly been focusing on enhancing the specific capacity and cycling performance with the application of new materials to electrodes (anode and cathode) and electrolyte.
Recham et al first demonstrated that fluorosulfates have a reversible intercalation mechanism with K, Na and Li, since then, other polyanionic compound such as K3V2(PO4)3, KVPO4F have been studied, while still limited to the complex synthesis process.
[6][7] Worth noting is an orthodox approach of using organic compound as cathode for potassium-ion battery, such as PTCDA, a red pigment which can bond with 11 potassium ion within single molecule.
[12] Conversion anodes which can form compound with potassium ion with boosted storage capacity and reversibility have also been studied to fit for potassium-ion battery.
[13] Due to the chemical activity higher than lithium, electrolytes for potassium ion battery requires more delicate engineering to address safety concerns.
Ionic liquid electrolyte offers new way to expand electrochemical window of potassium ion battery with much negative redox voltage and it's especially stable with graphite anode.
[14] Recently, solid polymer electrolyte for all-solid-state potassium-ion battery have attracted much attention due to its flexibility and enhanced safety, Feng et al proposed a poly (propylene carbonate)-KFSI solid polymer electrolyte with the frame work of cellulose non-woven membrane, with boosted ionic conductivity of 1.36
[15] Research on electrolyte for potassium-ion battery is focusing on achieving fast ion diffusion kinetics, stable SEI formation as well as enhanced safety.
[19][20] The chemical diffusion coefficient of K+ in the cell is higher than that of Li+ in lithium batteries, due to a smaller Stokes radius of solvated K+.
[23] Potassium batteries have been proposed for large-scale energy storage given its exceptional cyclability, but current prototypes only withstand a hundred charging cycles.