Hydrogenated C₆₀ as High-Capacity Stable Anode Materials for Li Ion Batteries

There is a need to develop high-capacity, stable anode materials for the next generation of lithium ion batteries that will power consumer electronics and automobiles of the future. This report describes a systematic experimental and theoretical evaluation of a series of hydrogenated fullerenes (C₆₀H_x) for use as high-capacity anodes in lithium ion batteries. It was discovered that there is an optimal degree of hydrogenation for C₆₀ to achieve reversible lithiation. Under the optimized conditions, C₆₀H_x was found to have a stable capacity of 588 mAh/g for over 600 cycles at a current density of 0.05 A/g. Extended cycling studies at higher current densities demonstrated that this material is stable for 2000 cycles. Theoretical modeling of this system determined that electronic structure changes due to hydrogenation is responsible for the favorable interaction of Li⁺ with C₆₀H_x. This study represents a unique methodology for increasing anode capacity and optimization of an anode's electrochemical properties by controlling the hydrogen content of the active material.