摘要
Electrochemical potassium ion intercalation into two-dimensional layered MoS2 was studied for the first time for potential applications in the anode in potassium-based batteries. X-ray diffraction analysis indicated that an intercalated potassium compound, hexagonal K0.4MoS2, formed during the intercalation process. Despite the size of K^＋, MoS2 was a long-life host for repetitive potassium ion intercalation and de-intercalation with a capacity retention of 97.5% after 200 cycles. The diffusion coefficient of the K^＋ ions in KxMoS2 was calculated based on the Randles-Sevcik equation. A higher K^＋ intercalation ratio not only encountered a much slower K^＋ diffusion rate in MoS2, but also induced MoS2 reduction. This study shows that metal dichalcogenides are promising potassium anode materials for emerging K-ion, K-O2, and K-S batteries.
Electrochemical potassium ion intercalation into two-dimensional layered MoS2 was studied for the first time for potential applications in the anode in potassium-based batteries. X-ray diffraction analysis indicated that an intercalated potassium compound, hexagonal K0.4MoS2, formed during the intercalation process. Despite the size of K^＋, MoS2 was a long-life host for repetitive potassium ion intercalation and de-intercalation with a capacity retention of 97.5% after 200 cycles. The diffusion coefficient of the K^＋ ions in KxMoS2 was calculated based on the Randles-Sevcik equation. A higher K^＋ intercalation ratio not only encountered a much slower K^＋ diffusion rate in MoS2, but also induced MoS2 reduction. This study shows that metal dichalcogenides are promising potassium anode materials for emerging K-ion, K-O2, and K-S batteries.
基金
Acknowledgements This work was financially supported by the National Science Foundation （No. IIP-1542995）. The authors also acknowledge Jonathan W. Crowe from Dr. Psaras L. McGrier＇s group for the help of the BET measurement.
