Emerging Non-Aqueous Potassium-Ion Batteries: Challenges and Opportunities

Abstract

The ever-increasing demand for storing renewable energy sources calls for novel battery technologies that are of sustainably low levelized energy cost. Research into battery chemistry has evolved to a stage where a plethora of choices based on earth-abundant elements can be compared during their development. One of the emerging candidates is the nonaqueous potassium-ion battery. K-ion’s unique properties as a charge carrier have aroused intense interest in exploring high-performing cathode and anode materials for this battery. Rapid progress has been made, where leading candidates of electrodes have been proposed, i.e., hard carbon as anode and Prussian white analogues as cathode. In this new battery technology’s infancy, it is our opinion that the focus should be given to potentially scalable, inexpensive electrode materials and the understanding of their cycle-life-property correlations. It may be the ultralong cycle life that differentiates potassium-ion batteries from sodium-ion batteries in the future market.

Development of P3-K0.69CrO2 as an ultra-high-performance cathode material for K-ion batteries

“…Although a few initial studies have demonstrated the electrochemically reversible potassium (de)intercalation reaction, the cycling stability and rate capability were unsatisfactory for efficient battery applications. 10,12 Therefore, the development of efficient cathode materials that can accommodate repeated extraction/insertion of large K + ions without sacrificing the structural stability remains a critical issue for the practical application of KIBs. Accordingly, we aimed to develop a Cr-based layered oxide as an efficient K intercalation host cathode, as prominent research groups have demonstrated the feasibility of reversible and fast Na-ion diffusion in a layered structured O3-NaCrO 2 cathode despite a large ionic size of Na (B1.02 Å).…”

Recent Progress and Perspective in Electrode Materials for K‐Ion Batteries

“…[82,83,88,89] Whereas the M B site is generally occupied by Fe, the use of different transition metals for the M A site leads to different K intercalation capacities and rate capability. [20] [88] A reversible discharge capacity of 137 mA h g −1 , which reflects near theoretical K intercalation (1.88 K), is achieved at a cycling rate of 30 mA g −1 . Note that in the first few charge cycles, more than the theoretical capacity (≈155 mA h g −1 ) was achieved, possibly due to parasitic reactions with the electrolyte and/ or electrochemical dehydration, as often observed in Prussian blue analogues.…”

“…[15][16][17] Recently, K-ion batteries (KIBs) have emerged as another possible energy storage system. [18][19][20] It is notable that the abundance of K resources in the Earth's crust and oceans is similar to that of Na (Figure 1a). [21,22] The cost of potassium carbonate The development of rechargeable batteries using K ions as charge carriers has recently attracted considerable attention in the search for cost-effective and large-scale energy storage systems.…”

Electrolytes, SEI Formation, and Binders: A Review of Nonelectrode Factors for Sodium‐Ion Battery Anodes

“…In the battery community, most research efforts are geared toward the development of newer, better, and more functional electrode materials. In many regards, this has enabled substantial progress with reversible batteries, such as Li‐ion batteries (LIBs), Na‐ion batteries (NIBs), and K‐ion batteries (KIBs) . New materials have shifted our perceptions of electrochemical energy storage: whereas it was once regarded as an ideal method to power small electronic devices, it is now expected to drive vehicles for hundreds of miles, and is touted as the solution to grid‐level energy storage.…”