CFx Derived Carbon-FeF_2 Nanocomposites for Reversible Lithium Storage

摘要

Lithium ion batteries are key energy storage devices that power today's consumer electronics. However, their energy density still falls short for transportation and large scale power storage applications. One way to increase the energy density of a battery is to use high energy density electrode materials. Current commercial Li-ion batteries mostly use insertion-based LiCoO_2 or LiFePO_4 as positive electrode materials. While LiCoO_2 is a layered compound with a specific capacity of 150 mAh g~(-1), LiFePO_4 is a framework compound whose capacity is 170 mAh g~(-1). Although both compounds show excellent reversibility with lithium, the specific capacity is limited to single electron redox reaction per molecule or even less. A valid approach to increase the energy density of electrode material is to utilize all possible redox states of a metal ion.