Alternative approaches for the fabrication of electrodes based on LiFePO4 as cathode in LIBs

Abstract

Lithium ion batteries are the power sources of choice for portable electronics, power tools and electric base transportation and they are ready to take over other niche and mainstream applications (from wearables to smart grid support to electric vehicles). Yet, this implies new requirements such as a combination of high energy and power densities, longer cycling life and, last but not least, substantially reduced costs. Most of the work presented in this thesis consisting of the optimization of low-cost and ecofriendly methods for the preparation of LiFePO4 (LFP) and the development of nanostructured and hybrid composites based on this cathode material and conductive polymers or conductive nanocarbons like graphene. Indeed, olivine-type LFP has been recognized as one of the most promising cathode materials for rechargeable Li batteries. Its advantages include high capacity, high stability, nontoxicity, and low cost. In order to overcome the well-known insulating nature of LFP, different methods, alternative to the conventional carbon-coating, were proposed and tested. We used low-temperature, low cost and environmental methods for synthesizing nanocrystalline LixFePO4 with the olivine structure and different morphologies and microstructures are described. As an alternative design of LFP electrodes, we developed electroactive LFP nanofluids based on the solid samples described before with the intention to use them as part of novel redox flow cells.