Two-Dimensional Iron Phosphorus Trisulfide as a High-Capacity Cathode for Lithium Primary Battery
Syama Lenus, Pallavi Thakur, Sai Smruti Samantaray, Tharangattu N. Narayanan, Zhengfei Dai
Abstract
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 ~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 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.