SbVO4 based high capacity potassium anode: a combination of conversion and alloying reactions

As the key to optimizing potassium ion batteries’ (PIBs) performance, the development of high capacity potassium anode is the footstone. Here, through a one-step solvothermal method, uniformly dispersed SbVO4 nanoparticles on the reduced graphene oxide nanosheets (SbVO4@RGO) were synthesized and used as PIBs anodes. SbVO4@RGO anode shows high capacity due to alloying and conversion reactions occur simultaneously in the cyclic process. The anode delivers a capacity as high as 447.9 mAh g−1 at 100 mA g−1. Besides, a cycling life of 500 cycles with small average capacity decay rate (only 0.106% per cycle) is also revealed. It was found in the initial discharge process, SbVO4 transforms into Sb and K3VO4. And in the following cycle Sb and K3VO4 simultaneously react with K+ via the alloying/de-alloying and conversion reaction, respectively. The present study of SbVO4@RGO may provide insight for high performance alloying-based/conversion-based potassium anodes.