Hysteresis observed in quasi open-circuit voltage measurements of lithium insertion in hydrogen-containing carbons

High capacities with large hysteresis were observed during lithium insertion in hydrogen-containing carbons heated at temperatures near 700 °C. Quasi open-circuit voltage (OCV) measurements were used to study these materials. Using a simple model developed previously [1], we can qualitatively model the result of the OCV measurement. It is believed that the lithium atoms bind near aromatic hydrogen at edge of each graphene layer in the materials. This activated process involves a carbon-carbon bonding change from (sp)2 to (sp)3 leading to large hysteresis during lithium insertion.