Chapter 17 - Fluorine-intercalated graphite for lithium batteries

Abstract

This chapter discusses the problems with carbon reactivity with fluorine. It focuses on a new family of compounds obtained from the fluorination post-treatment of graphite fluoride prepared at room temperature. Using fluorine in the gas phase is, in practice, impossible not only because of its very high reactivity with most materials even at room temperature, but also because of its presence in a very small amount in the gas phase which, consequently, produces a very low energy in the system. Thus, the use of a solid-state support for fluorine storage is required. The use of graphite and highly graphitized carbon as starting materials is more suitable. At room temperature, the reactivity of fluorine against graphite is vastly improved by the presence of a volatile fluoride–anhydrous HF gaseous mixture. The chapter discusses the synthesis of modified low-temperature fluorinated graphite and evolution of the C–F bonding during the fluorination post-treatment. It also describes electrochemical studies of fluorinated graphite used as cathodic materials in lithium batteries. It concluded with a discussion on designing materials with an adjusted capacity–voltage couple.