Phenyl Tellurosulfides as Cathode Materials for Rechargeable Lithium Batteries.

Phenyl ditelluride (PDTe) as a cathode material for rechargeable batteries has a low specific capacity (130.9 mAh g-1) due to limited active sites (two). To increase its capacity, additional active species need to be added to the structure of PDTe, like sulfur. Here, phenyl tellurosulfide (PDTeS) and phenyl tellurodisulfide (PDTeS2) can be formed via addition reactions and have specific capacities of 242.8 and 339.6 mAh g-1, respectively. The products are characterized by mass spectrometry and Raman spectroscopy. The Li/PDTeSn (n = 1-2) cells exhibit high material utilization (>85%) and unique redox mechanism. They can be cycled stably for more than 1000 cycles at an areal mass loading of 1.1 mg cm-2 and maintain capacity retentions of >72% after 100 cycles with PDTeSn loading of ∼6 mg cm-2. Moreover, the Li/PDTeS2 cell achieves a specific energy of up to 695 Wh kg-1 even when the electrolyte/PDTeS2 ratio is as low as 2.5 µL mg-1. The successful synthesis and application of PDTeSn prove that they are promising cathode materials for rechargeable lithium batteries.

A phenyl S-Te bond with unique redox activity in dilute electrolyte of a lithium battery.

Phenyl tellurosulfide (PhS-TePh) was used to study the redox activity of the S-Te bond in lithium batteries. PhS-TePh formed a dynamic covalent network during lithiation, which provided a balance between responsiveness and stability to facilitate ion and electron transfer, enabling Li/PhS-TePh cells to achieve stable cycling and excellent rate performance in dilute electrolyte.