Low temperature preparation and electrochemical properties of LiFeSi ₂O₆

The growing demand for Li-ion batteries requires the development of inexpensive materials that can be made in a sustainable fashion. Here we report a new low-temperature preparation for and the first electrochemical characterization of LiFeSi₂O₆, a hugely Earth-abundant, rock-forming mineral. We have found that LiFeSi₂O₆ undergoes a reversible electrochemical reaction against Li centered around 2 V with capacities near 60% of the theoretical maximum. We employ high resolution synchrotron X-ray and neutron diffraction to characterize the structure and correlate the rigid connectivity of the framework with the very slow kinetics of diffusion.