Potassium-ion battery

A potassium-ion battery or K-ion battery (abbreviated as KIB) is a type of

It was invented by the Iranian/American chemist Ali Eftekhari (President of the American Nano Society) in 2004.[1]

The prototype device used a potassium anode and a Prussian blue compound as the cathode material^[1] for its high electrochemical stability.^[2] The prototype was successfully used for more than 500 cycles. 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.^[3] For example, the conventional anode material graphite has been shown that it can be used as an anode in a potassium-ion battery.^[4]

In 2024, Group1, created Kristonite for the cathode.

After the invention of potassium-ion battery with the prototype device, researchers have increasingly been focusing on enhancing the

Same as the case of lithium-ion battery, graphite could also accommodate the intercalation of potassium within electrochemical process.^[11] Whereas with different kinetics, graphite anodes suffer from low capacity retention during cycling within potassium-ion batteries. Thus, the approach of structure engineering of graphite anode is needed to achieve stable performance. Other types of carbonaceous materials besides graphite have been employed as anode material for potassium-ion battery, such as expanded graphite, carbon nanotubes, carbon nanofibers and also nitrogen or phosphorus-doped carbon materials.^[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. To buffer the volume change of conversion anode, a carbon material matrix is always applied such as MoS₂@rGO, Sb₂S₃-SNG, SnS₂-rGO and so on.^[13]

Due to the chemical activity higher than lithium, electrolytes for potassium ion battery requires more delicate engineering to address safety concerns. Commercial ethylene carbonate (EC) and diethyl carbonate (DEC) or other traditional ether/ester liquid electrolyte showed poor cycling performance and fast capacity degradation due to the Lewis acidity of potassium, also the highly flammable feature of it has prevented further application. 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${\displaystyle \times }$10⁻⁵ S cm⁻¹.^[15] Research on electrolyte for potassium-ion battery is focusing on achieving fast ion diffusion kinetics, stable SEI formation as well as enhanced safety.

Along with the sodium ion, potassium-ion is the prime chemistry replacement candidate for lithium-ion batteries.^[16] The potassium-ion has certain advantages over similar lithium-ion (e.g., lithium-ion batteries): the cell design is simple and both the material and the fabrication procedures are cheaper. The key advantage is the abundance and low cost of potassium in comparison with lithium, which makes potassium batteries a promising candidate for large scale batteries such as household energy storage and electric vehicles.^[17] Another advantage of a potassium-ion battery over a lithium-ion battery is potentially faster charging.^[18]

The

In 2005, a potassium battery that uses molten electrolyte of KPF₆ was patented.^[21][22] In 2007, Chinese company Starsway Electronics marketed the first potassium battery-powered portable media player as a high-energy device.^[23]

Potassium batteries have been proposed for large-scale energy storage given its exceptional cyclability, but current prototypes only withstand a hundred charging cycles.^[24][25][26]

As of 2019, five main issues are preventing widespread use of the K-ion battery technology: low diffusion of potassium ions through a solid electrode, as well as breakdown of the potassium after repeated cycles due to changes in volume, side reactions, growth of dendrites and poor heat dissipation. Researchers estimate that it could take as long as 20 years to figure all these problems out.^[27][28]

The interesting and unique feature of the potassium-ion battery in comparison with other types of batteries is that life on Earth is based on biological potassium-ion batteries. K⁺ is the key charge carrier in plants. Circulation of K⁺ ions facilitates energy storage in plants by forming decentralized potassium batteries.^[29] This is not only an iconic feature of potassium-ion batteries but also indicates how important it is to understand the role of K⁺ charge carriers to understand the living mechanism of plants.

Researchers demonstrated a potassium-air battery (K-O₂) with low overpotential. Its charge/discharge potential gap of about 50 mV is the lowest reported value in metal−air batteries. This provides a round-trip energy efficiency of >95%. In comparison, lithium–air batteries (Li-O₂) have a much higher overpotential of 1–1.5 V, which results in 60% round-trip efficiency.^[30]

• List of battery types
• Lithium–air battery
• Thin film lithium-ion battery
• Alkali metal-ion battery
  • Lithium-ion battery
  • Sodium-ion battery
  • Potassium-ion battery
  • Calcium-ion battery