Two-Dimensional Iron Phosphorus Trisulfide as a High-Capacity Cathode for Lithium Primary Battery

Metal phosphorus trichalcogenide (MPX3) materials have aroused substantial curiosity in the evolution of electrochemical storage devices due to their environment-friendliness and advantageous X-P synergic effects. The interesting intercalation properties generated due to the presence of wide van der Waals gaps along with high theoretical specific capacity pose MPX3 as a potential host electrode in lithium batteries. Herein, we synthesized two-dimensional iron thio-phosphate (FePS3) nanoflakes via a salt-template synthesis method, using low-temperature time synthesis conditions in single step. The electrochemical application of FePS3 has been explored through the construction of a high-capacity lithium primary battery (LPB) coin cell with FePS3 nanoflakes as the cathode. The galvanostatic discharge studies on the assembled LPB exhibit a high specific capacity of similar to 1791 mAh g(-1) and high energy density of similar to 2500 Wh Kg(-1) along with a power density of similar to 5226 W Kg(-1), some of the highest reported values, indicating FePS3's potential in low-cost primary batteries. A mechanistic insight into the observed three-staged discharge mechanism of the FePS3-based primary cell resulting in the high capacity is provided, and the findings are supported via post-mortem analyses at the electrode scale, using both electrochemical- as well as photoelectron spectroscopy-based studies.

Automated summary

Metal phosphorus trichalcogenide (MPX3) materials have attracted attention as potential host electrodes in lithium batteries due to their environment-friendliness and advantageous X-P synergic effects. Two-dimensional iron thio-phosphate (FePS3) nanoflakes were synthesized using a salt-template synthesis method, and their electrochemical application in a high-capacity lithium primary battery (LPB) demonstrated a high specific capacity, energy density, and power density. The observed discharge mechanism of the FePS3-based primary cell and the findings from post-mortem analyses provide mechanistic insight into its high capacity.