Unraveling the effect of salt chemistry on long-durability high-phosphorus-concentration anode for potassium ion batteries

Fourier transform infrared (FTIR) spectroscopic mapping was carried out to study the side reactions and distribution of the SEI layer formed in various electrolytes during cycling. It was found that KFSI electrolyte as an alternative potassium salt in carbonate electrolytes, facilitates in constructing stable and even SEI film, possibly avoid excessive side-reactions, and results in improved electrochemical performance in PIBs.225