SnCo Nanoalloy/Graphene Anode Constructed by Microfluidic-Assisted Nanoprecipitation for Potassium-Ion Batteries

Potassium-ion batteries have attracted substantial interest due to abundant resources and comparable electrochemical performance with lithium-ion batteries. Although plenty of graphene-based materials with ultrahigh performance have been designed, in practice, the dendrite growth induced by the capacitive-dominated potassium storage mechanism and the poor repeatability resulting from the complicated process are worrisome. To address these issues, it is envisaged that embedding SnCo nanoalloys in a graphene nanosheet matrix (SnCo NAs/G) can be an effective strategy for the following two reasons: (1) The embedded SnCo NAs are responsible for expanding the interlayer space and facilitating the potassium-ion diffusion in a graphene nanosheet matrix and (2) the combination of the microfluidic technology and the organic molecule confinement reaction endows the repeatability and large-scale production. As a result, the SnCo NAs/G-L anode is prepared with a low content of SnCo NAs (9.16 wt %). It shows advantages in the electrochemical performance as compared to the graphite anode. A reversible specific capacity of 165 mA h g-1 at 50 mA g-1 over 100 cycles is exhibited by SnCo NAs/G-L. It has a retention capacity of 179 mA h g-1, that is, 78.8% is recovered after charging at 500 mA g-1. Moreover, the intercalation reaction as the dominant potassium storage mechanism is beneficial for avoiding the safety problems arising from potassium dendrite growth. More interestingly, graphite-based composites constructed by the microfluidic technology successfully prove the high potential for large-scale production.

Automated summary

By embedding SnCo nanoalloys in a graphene nanosheet matrix, the issues of dendrite growth and poor repeatability in potassium-ion batteries can be effectively addressed. The material shows promising electrochemical performance and potential for large-scale production.