Applications of Lithium based Supersonic Conductors for Solid State Battery Devices

Abstract

As technology advances, the need for alternative sources of energy newlinearises. Batteries have been studied by many different research groups newlineas a proper way to power everything from small devices such as cell newlinephones to large units such as cars and factory machinery. Specifically, newlinelithium-ion batteries have been vigorously studied due to their numerous newlinebenefits such as high energy density, high voltage and a low selfdischarge rate. Thin-film lithium-ion batteries have been researched, but newlinenot many successful prototypes have been developed. These newlineprototypes have incorporated active materials such as LiCoO2, LiMn2O4 newlineand Li2MSiO4 (where M=Mn, Fe, Ni, etc.). Based on prior research, newlinemany of these materials vary in properties such as theoretical capacity, newlineconductivity and cycling life. Lithium silicates, with two lithium atoms in newlineeach molecule, have been proposed as candidates with higher newlinetheoretical capacity. Pure phase compounds with a general formula of newlineLi2MSiO4 (M=Mn, Fe, Co) have been tested and each has manifested newlineunique drawbacks. In this project we want to test the hypothesis that newlineLi2MSiO4 with mixed M of Fe and Mn might provide superior newlineperformance to the pure phases as observed in the case of the layered newlineLiMO2 cathodes. We first studied the synthesis of Li2FexMn1-xSiO4 newlinethrough a sol gel process. Li2FexMn1-xSiO4 materials with different Mn to newlineFe ratios have been synthesized. Carbon coating was used to increase newlinethe active material s conductivity. We then characterized the composites newlinethrough an array of tests, including XRD, SEM and coin-cell battery newlinetesting. The results are discussed in this report. newline