Building carbon cloth-based dendrite-free potassium metal anodes for potassium metal pouch cells

Potassium (K) metal batteries are identified as some of the most potential candidates for next-generation energy storage devices due to the abundant reserves, low redox potential and high theoretical capacity of K metal. However, the practical application of K metal batteries is severely hindered by the uncontrollable growth of K dendrites. Herein, a dendrite-free and high-performance K metal anode was obtained by constraining K metal on SnO2-modified commercial carbon cloth (K-CC@SnO2). In the K-CC@SnO2 structure, K metal wraps the SnO2 particles and forms a closely connected structure with the carbon cloth. CC@SnO2 not only shows excellent potassiophilicity, but also possesses high electronic conductivity and large void spaces, which can induce the homogeneous deposition of K metal and accommodate the large volume changes of K during the plating/stripping processes. Consequently, the as-constructed K-CC@SnO2 anodes exhibit low polarization and long cycling life with a dendrite-free morphology in symmetric cells with a carbonate-based electrolyte. In addition, a perylene-3,4,9,10-tetracarboxylic diimide (PTCDI)||K-CC@SnO2 full cell shows excellent rate performance (112.5 mA h g(-1) @ 5 A g(-1)) and ultralong cycling life (up to 10 000 cycles). A PTCDI||K-CC@SnO2 pouch cell was successfully assembled and it delivers a long cycling life of 500 cycles with an energy density of 274 W h kg(-1). These results indicate that a simple and effective strategy has been proposed for the development of K metal anodes with commercialization potential.

Automated summary

Potassium (K) metal batteries are considered promising energy storage devices due to the properties of K metal. However, the growth of K dendrites poses a challenge. A dendrite-free K metal anode was achieved by constraining K metal on SnO2-modified commercial carbon cloth. This structure exhibited low polarization, long cycling life, and good performance in symmetric cells and full cells. The results suggest a potential for commercialization of K metal anodes.