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

Metal phosphorus trichalcogenide (MPX(3)) 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 MPX(3) as a potential host electrode in lithium batteries. Herein, we synthesized two-dimensional iron thio-phosphate (FePS(3)) nanoflakes via a salt-template synthesis method, using low-temperature time synthesis conditions in single step. The electrochemical application of FePS(3) has been explored through the construction of a high-capacity lithium primary battery (LPB) coin cell with FePS(3) nanoflakes as the cathode. The galvanostatic discharge studies on the assembled LPB exhibit a high specific capacity of ~1791 mAh g(−1) and high energy density of ~2500 Wh Kg(−1) along with a power density of ~5226 W Kg(−1), some of the highest reported values, indicating FePS(3)′s potential in low-cost primary batteries. A mechanistic insight into the observed three-staged discharge mechanism of the FePS(3)-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.