Phosphorus-Based Alloy Materials for Advanced Potassium-Ion Battery Anode

摘要

Potassium-ion batteries (PIBs) are interesting as one of the alternative metal-ion battery systems to lithium-ion batteries (LIBs) due to the abundance and low cost of potassium. We have herein investigated Sn_4P_3/C composite as a novel anode material for PIBs. The electrode delivered a reversible capacity of 384.8 mA h g~(-1) at 50 mA g~(-1) and a good rate capability of 221.9 mA h g~(-1), even at 1 A g~(-1). Its electrochemical performance is better than any anode material reported so far for PIBs. It was also found that the Sn_4P_3/C electrode displays a discharge potential plateau of 0.1 V in PIBs, slightly higher than for sodium-ion batteries (SIBs) (0.01 V), and well above the plating potential of metal. This diminishes the formation of dendrites during cycling, and thus Sn_4P_3 is a relatively safe anode material, especially for application in large-scale energy storage, where large amounts of electrode materials are used. Furthermore, a possible reaction mechanism of the Sn_4P_3/C composite as PIB anode is proposed. This work may open up a new avenue for further development of alloy-based anodes with high capacity and long cycle life for PIBs.