(Invited) Halogenconversion-Intercalation Chemistry in Graphite

摘要

We report a halogen conversion-intercalation chemistry in graphite that produces composite electrodes with a capacity of 243 milliamperehours per gram (for the total weight of the electrode) at an average potential of 4.2 volts versus Li/Li+. Experimental characterization and modelling attribute this high specific capacity to a densely packed stage-I graphite intercalation compound, C3.5[Br0.5C10.5], which can form reversibly in water-in-bisalt electrolyte. By coupling this cathode with a passivated graphite anode, we create a 4-voltclass aqueous Li-ion full cell with an energy density of 460 watthours per kilogram of total composite electrode and about 100 per cent Coulombic efficiency. This anion conversion-intercalation mechanism combines the high energy densities of the conversion reactions, the excellent reversibility of the intercalation mechanism and the improved safety of aqueous batteries.