Novel Supported Low-Temperature Solid Molten Salt (SMS) Anode Materials for Li-ion Batteries

The Solid Molten Salt-Fe2O3@Polypyrrole (SMS-Fe2O3@PPy) materials as anode electrode are successfully synthesized by a two-step method and applied for lithium-ion batteries (LIBs). The SMS-Fe2O3@PPy electrode is composed of Fe-based solid molten salt (SMS), PPy and octahedral Fe2O3 nanoparticles. Importantly, the introduction of PPy not only can provide a coating to suppress the volume expansion but also improve the electrical conductivity of the material. The elegant synergy effectively reduces the volume expansion of the material during the Li+ insertion/extraction process. As an anode for the LIBs, the SMS-Fe2O3@PPy electrode deliver reversible capacities of 1346 mAh/g at 100 mA g-1, good cycle stability of 1198 mAh/g even after 1000 cycles at 500 mA g-1 and excellent rate performance of 110 mAh/g even at 50 A g-1. It is found that the SMS can provide a large amount of LiH by combining with Li+ in the discharge process. The potential adsorption sites (site A and site B) from SMS were obtained by Density Functional theory (DFT) methods, and the attraction capacity of SMS to Li+ increased with the increasing of the number of electrons around SMS. All above unique advantages lead to a large specific capacity as well as excellent cycling stability, resulting in a considerable electrochemical performance. It can be seen from the excellent electrochemical performance of SMS-Fe2O3@PPy electrode that portends this will be a promising material for high-performance electrochemical devices.